diff options
Diffstat (limited to 'Documentation/technical')
25 files changed, 892 insertions, 161 deletions
diff --git a/Documentation/technical/api-allocation-growing.txt b/Documentation/technical/api-allocation-growing.txt index 43dbe09f73..542946b1ba 100644 --- a/Documentation/technical/api-allocation-growing.txt +++ b/Documentation/technical/api-allocation-growing.txt @@ -5,7 +5,9 @@ Dynamically growing an array using realloc() is error prone and boring. Define your array with: -* a pointer (`ary`) that points at the array, initialized to `NULL`; +* a pointer (`item`) that points at the array, initialized to `NULL` + (although please name the variable based on its contents, not on its + type); * an integer variable (`alloc`) that keeps track of how big the current allocation is, initialized to `0`; @@ -13,22 +15,22 @@ Define your array with: * another integer variable (`nr`) to keep track of how many elements the array currently has, initialized to `0`. -Then before adding `n`th element to the array, call `ALLOC_GROW(ary, n, +Then before adding `n`th element to the item, call `ALLOC_GROW(item, n, alloc)`. This ensures that the array can hold at least `n` elements by calling `realloc(3)` and adjusting `alloc` variable. ------------ -sometype *ary; +sometype *item; size_t nr; size_t alloc for (i = 0; i < nr; i++) - if (we like ary[i] already) + if (we like item[i] already) return; /* we did not like any existing one, so add one */ -ALLOC_GROW(ary, nr + 1, alloc); -ary[nr++] = value you like; +ALLOC_GROW(item, nr + 1, alloc); +item[nr++] = value you like; ------------ You are responsible for updating the `nr` variable. diff --git a/Documentation/technical/api-argv-array.txt b/Documentation/technical/api-argv-array.txt new file mode 100644 index 0000000000..a959517b23 --- /dev/null +++ b/Documentation/technical/api-argv-array.txt @@ -0,0 +1,63 @@ +argv-array API +============== + +The argv-array API allows one to dynamically build and store +NULL-terminated lists. An argv-array maintains the invariant that the +`argv` member always points to a non-NULL array, and that the array is +always NULL-terminated at the element pointed to by `argv[argc]`. This +makes the result suitable for passing to functions expecting to receive +argv from main(), or the link:api-run-command.html[run-command API]. + +The link:api-string-list.html[string-list API] is similar, but cannot be +used for these purposes; instead of storing a straight string pointer, +it contains an item structure with a `util` field that is not compatible +with the traditional argv interface. + +Each `argv_array` manages its own memory. Any strings pushed into the +array are duplicated, and all memory is freed by argv_array_clear(). + +Data Structures +--------------- + +`struct argv_array`:: + + A single array. This should be initialized by assignment from + `ARGV_ARRAY_INIT`, or by calling `argv_array_init`. The `argv` + member contains the actual array; the `argc` member contains the + number of elements in the array, not including the terminating + NULL. + +Functions +--------- + +`argv_array_init`:: + Initialize an array. This is no different than assigning from + `ARGV_ARRAY_INIT`. + +`argv_array_push`:: + Push a copy of a string onto the end of the array. + +`argv_array_pushl`:: + Push a list of strings onto the end of the array. The arguments + should be a list of `const char *` strings, terminated by a NULL + argument. + +`argv_array_pushf`:: + Format a string and push it onto the end of the array. This is a + convenience wrapper combining `strbuf_addf` and `argv_array_push`. + +`argv_array_pop`:: + Remove the final element from the array. If there are no + elements in the array, do nothing. + +`argv_array_clear`:: + Free all memory associated with the array and return it to the + initial, empty state. + +`argv_array_detach`:: + Detach the argv array from the `struct argv_array`, transfering + ownership of the allocated array and strings. + +`argv_array_free_detached`:: + Free the memory allocated by a `struct argv_array` that was later + detached and is now no longer needed. diff --git a/Documentation/technical/api-builtin.txt b/Documentation/technical/api-builtin.txt index b0cafe87be..4a4228b896 100644 --- a/Documentation/technical/api-builtin.txt +++ b/Documentation/technical/api-builtin.txt @@ -5,7 +5,7 @@ Adding a new built-in --------------------- There are 4 things to do to add a built-in command implementation to -git: +Git: . Define the implementation of the built-in command `foo` with signature: @@ -23,7 +23,7 @@ where options is the bitwise-or of: `RUN_SETUP`:: - Make sure there is a git directory to work on, and if there is a + Make sure there is a Git directory to work on, and if there is a work tree, chdir to the top of it if the command was invoked in a subdirectory. If there is no work tree, no chdir() is done. diff --git a/Documentation/technical/api-config.txt b/Documentation/technical/api-config.txt new file mode 100644 index 0000000000..230b3a0f60 --- /dev/null +++ b/Documentation/technical/api-config.txt @@ -0,0 +1,140 @@ +config API +========== + +The config API gives callers a way to access Git configuration files +(and files which have the same syntax). See linkgit:git-config[1] for a +discussion of the config file syntax. + +General Usage +------------- + +Config files are parsed linearly, and each variable found is passed to a +caller-provided callback function. The callback function is responsible +for any actions to be taken on the config option, and is free to ignore +some options. It is not uncommon for the configuration to be parsed +several times during the run of a Git program, with different callbacks +picking out different variables useful to themselves. + +A config callback function takes three parameters: + +- the name of the parsed variable. This is in canonical "flat" form: the + section, subsection, and variable segments will be separated by dots, + and the section and variable segments will be all lowercase. E.g., + `core.ignorecase`, `diff.SomeType.textconv`. + +- the value of the found variable, as a string. If the variable had no + value specified, the value will be NULL (typically this means it + should be interpreted as boolean true). + +- a void pointer passed in by the caller of the config API; this can + contain callback-specific data + +A config callback should return 0 for success, or -1 if the variable +could not be parsed properly. + +Basic Config Querying +--------------------- + +Most programs will simply want to look up variables in all config files +that Git knows about, using the normal precedence rules. To do this, +call `git_config` with a callback function and void data pointer. + +`git_config` will read all config sources in order of increasing +priority. Thus a callback should typically overwrite previously-seen +entries with new ones (e.g., if both the user-wide `~/.gitconfig` and +repo-specific `.git/config` contain `color.ui`, the config machinery +will first feed the user-wide one to the callback, and then the +repo-specific one; by overwriting, the higher-priority repo-specific +value is left at the end). + +The `git_config_with_options` function lets the caller examine config +while adjusting some of the default behavior of `git_config`. It should +almost never be used by "regular" Git code that is looking up +configuration variables. It is intended for advanced callers like +`git-config`, which are intentionally tweaking the normal config-lookup +process. It takes two extra parameters: + +`filename`:: +If this parameter is non-NULL, it specifies the name of a file to +parse for configuration, rather than looking in the usual files. Regular +`git_config` defaults to `NULL`. + +`respect_includes`:: +Specify whether include directives should be followed in parsed files. +Regular `git_config` defaults to `1`. + +There is a special version of `git_config` called `git_config_early`. +This version takes an additional parameter to specify the repository +config, instead of having it looked up via `git_path`. This is useful +early in a Git program before the repository has been found. Unless +you're working with early setup code, you probably don't want to use +this. + +Reading Specific Files +---------------------- + +To read a specific file in git-config format, use +`git_config_from_file`. This takes the same callback and data parameters +as `git_config`. + +Value Parsing Helpers +--------------------- + +To aid in parsing string values, the config API provides callbacks with +a number of helper functions, including: + +`git_config_int`:: +Parse the string to an integer, including unit factors. Dies on error; +otherwise, returns the parsed result. + +`git_config_ulong`:: +Identical to `git_config_int`, but for unsigned longs. + +`git_config_bool`:: +Parse a string into a boolean value, respecting keywords like "true" and +"false". Integer values are converted into true/false values (when they +are non-zero or zero, respectively). Other values cause a die(). If +parsing is successful, the return value is the result. + +`git_config_bool_or_int`:: +Same as `git_config_bool`, except that integers are returned as-is, and +an `is_bool` flag is unset. + +`git_config_maybe_bool`:: +Same as `git_config_bool`, except that it returns -1 on error rather +than dying. + +`git_config_string`:: +Allocates and copies the value string into the `dest` parameter; if no +string is given, prints an error message and returns -1. + +`git_config_pathname`:: +Similar to `git_config_string`, but expands `~` or `~user` into the +user's home directory when found at the beginning of the path. + +Include Directives +------------------ + +By default, the config parser does not respect include directives. +However, a caller can use the special `git_config_include` wrapper +callback to support them. To do so, you simply wrap your "real" callback +function and data pointer in a `struct config_include_data`, and pass +the wrapper to the regular config-reading functions. For example: + +------------------------------------------- +int read_file_with_include(const char *file, config_fn_t fn, void *data) +{ + struct config_include_data inc = CONFIG_INCLUDE_INIT; + inc.fn = fn; + inc.data = data; + return git_config_from_file(git_config_include, file, &inc); +} +------------------------------------------- + +`git_config` respects includes automatically. The lower-level +`git_config_from_file` does not. + +Writing Config Files +-------------------- + +TODO diff --git a/Documentation/technical/api-credentials.txt b/Documentation/technical/api-credentials.txt new file mode 100644 index 0000000000..516fda7412 --- /dev/null +++ b/Documentation/technical/api-credentials.txt @@ -0,0 +1,268 @@ +credentials API +=============== + +The credentials API provides an abstracted way of gathering username and +password credentials from the user (even though credentials in the wider +world can take many forms, in this document the word "credential" always +refers to a username and password pair). + +This document describes two interfaces: the C API that the credential +subsystem provides to the rest of Git, and the protocol that Git uses to +communicate with system-specific "credential helpers". If you are +writing Git code that wants to look up or prompt for credentials, see +the section "C API" below. If you want to write your own helper, see +the section on "Credential Helpers" below. + +Typical setup +------------- + +------------ ++-----------------------+ +| Git code (C) |--- to server requiring ---> +| | authentication +|.......................| +| C credential API |--- prompt ---> User ++-----------------------+ + ^ | + | pipe | + | v ++-----------------------+ +| Git credential helper | ++-----------------------+ +------------ + +The Git code (typically a remote-helper) will call the C API to obtain +credential data like a login/password pair (credential_fill). The +API will itself call a remote helper (e.g. "git credential-cache" or +"git credential-store") that may retrieve credential data from a +store. If the credential helper cannot find the information, the C API +will prompt the user. Then, the caller of the API takes care of +contacting the server, and does the actual authentication. + +C API +----- + +The credential C API is meant to be called by Git code which needs to +acquire or store a credential. It is centered around an object +representing a single credential and provides three basic operations: +fill (acquire credentials by calling helpers and/or prompting the user), +approve (mark a credential as successfully used so that it can be stored +for later use), and reject (mark a credential as unsuccessful so that it +can be erased from any persistent storage). + +Data Structures +~~~~~~~~~~~~~~~ + +`struct credential`:: + + This struct represents a single username/password combination + along with any associated context. All string fields should be + heap-allocated (or NULL if they are not known or not applicable). + The meaning of the individual context fields is the same as + their counterparts in the helper protocol; see the section below + for a description of each field. ++ +The `helpers` member of the struct is a `string_list` of helpers. Each +string specifies an external helper which will be run, in order, to +either acquire or store credentials. See the section on credential +helpers below. This list is filled-in by the API functions +according to the corresponding configuration variables before +consulting helpers, so there usually is no need for a caller to +modify the helpers field at all. ++ +This struct should always be initialized with `CREDENTIAL_INIT` or +`credential_init`. + + +Functions +~~~~~~~~~ + +`credential_init`:: + + Initialize a credential structure, setting all fields to empty. + +`credential_clear`:: + + Free any resources associated with the credential structure, + returning it to a pristine initialized state. + +`credential_fill`:: + + Instruct the credential subsystem to fill the username and + password fields of the passed credential struct by first + consulting helpers, then asking the user. After this function + returns, the username and password fields of the credential are + guaranteed to be non-NULL. If an error occurs, the function will + die(). + +`credential_reject`:: + + Inform the credential subsystem that the provided credentials + have been rejected. This will cause the credential subsystem to + notify any helpers of the rejection (which allows them, for + example, to purge the invalid credentials from storage). It + will also free() the username and password fields of the + credential and set them to NULL (readying the credential for + another call to `credential_fill`). Any errors from helpers are + ignored. + +`credential_approve`:: + + Inform the credential subsystem that the provided credentials + were successfully used for authentication. This will cause the + credential subsystem to notify any helpers of the approval, so + that they may store the result to be used again. Any errors + from helpers are ignored. + +`credential_from_url`:: + + Parse a URL into broken-down credential fields. + +Example +~~~~~~~ + +The example below shows how the functions of the credential API could be +used to login to a fictitious "foo" service on a remote host: + +----------------------------------------------------------------------- +int foo_login(struct foo_connection *f) +{ + int status; + /* + * Create a credential with some context; we don't yet know the + * username or password. + */ + + struct credential c = CREDENTIAL_INIT; + c.protocol = xstrdup("foo"); + c.host = xstrdup(f->hostname); + + /* + * Fill in the username and password fields by contacting + * helpers and/or asking the user. The function will die if it + * fails. + */ + credential_fill(&c); + + /* + * Otherwise, we have a username and password. Try to use it. + */ + status = send_foo_login(f, c.username, c.password); + switch (status) { + case FOO_OK: + /* It worked. Store the credential for later use. */ + credential_accept(&c); + break; + case FOO_BAD_LOGIN: + /* Erase the credential from storage so we don't try it + * again. */ + credential_reject(&c); + break; + default: + /* + * Some other error occured. We don't know if the + * credential is good or bad, so report nothing to the + * credential subsystem. + */ + } + + /* Free any associated resources. */ + credential_clear(&c); + + return status; +} +----------------------------------------------------------------------- + + +Credential Helpers +------------------ + +Credential helpers are programs executed by Git to fetch or save +credentials from and to long-term storage (where "long-term" is simply +longer than a single Git process; e.g., credentials may be stored +in-memory for a few minutes, or indefinitely on disk). + +Each helper is specified by a single string in the configuration +variable `credential.helper` (and others, see linkgit:git-config[1]). +The string is transformed by Git into a command to be executed using +these rules: + + 1. If the helper string begins with "!", it is considered a shell + snippet, and everything after the "!" becomes the command. + + 2. Otherwise, if the helper string begins with an absolute path, the + verbatim helper string becomes the command. + + 3. Otherwise, the string "git credential-" is prepended to the helper + string, and the result becomes the command. + +The resulting command then has an "operation" argument appended to it +(see below for details), and the result is executed by the shell. + +Here are some example specifications: + +---------------------------------------------------- +# run "git credential-foo" +foo + +# same as above, but pass an argument to the helper +foo --bar=baz + +# the arguments are parsed by the shell, so use shell +# quoting if necessary +foo --bar="whitespace arg" + +# you can also use an absolute path, which will not use the git wrapper +/path/to/my/helper --with-arguments + +# or you can specify your own shell snippet +!f() { echo "password=`cat $HOME/.secret`"; }; f +---------------------------------------------------- + +Generally speaking, rule (3) above is the simplest for users to specify. +Authors of credential helpers should make an effort to assist their +users by naming their program "git-credential-$NAME", and putting it in +the $PATH or $GIT_EXEC_PATH during installation, which will allow a user +to enable it with `git config credential.helper $NAME`. + +When a helper is executed, it will have one "operation" argument +appended to its command line, which is one of: + +`get`:: + + Return a matching credential, if any exists. + +`store`:: + + Store the credential, if applicable to the helper. + +`erase`:: + + Remove a matching credential, if any, from the helper's storage. + +The details of the credential will be provided on the helper's stdin +stream. The exact format is the same as the input/output format of the +`git credential` plumbing command (see the section `INPUT/OUTPUT +FORMAT` in linkgit:git-credential[7] for a detailed specification). + +For a `get` operation, the helper should produce a list of attributes +on stdout in the same format. A helper is free to produce a subset, or +even no values at all if it has nothing useful to provide. Any provided +attributes will overwrite those already known about by Git. + +For a `store` or `erase` operation, the helper's output is ignored. +If it fails to perform the requested operation, it may complain to +stderr to inform the user. If it does not support the requested +operation (e.g., a read-only store), it should silently ignore the +request. + +If a helper receives any other operation, it should silently ignore the +request. This leaves room for future operations to be added (older +helpers will just ignore the new requests). + +See also +-------- + +linkgit:gitcredentials[7] + +linkgit:git-config[5] (See configuration variables `credential.*`) diff --git a/Documentation/technical/api-directory-listing.txt b/Documentation/technical/api-directory-listing.txt index add6f435b5..1f349b28ae 100644 --- a/Documentation/technical/api-directory-listing.txt +++ b/Documentation/technical/api-directory-listing.txt @@ -9,37 +9,40 @@ Data structure -------------- `struct dir_struct` structure is used to pass directory traversal -options to the library and to record the paths discovered. The notable -options are: +options to the library and to record the paths discovered. A single +`struct dir_struct` is used regardless of whether or not the traversal +recursively descends into subdirectories. + +The notable options are: `exclude_per_dir`:: The name of the file to be read in each directory for excluded files (typically `.gitignore`). -`collect_ignored`:: +`flags`:: - Include paths that are to be excluded in the result. + A bit-field of options: -`show_ignored`:: +`DIR_SHOW_IGNORED`::: The traversal is for finding just ignored files, not unignored files. -`show_other_directories`:: +`DIR_SHOW_OTHER_DIRECTORIES`::: Include a directory that is not tracked. -`hide_empty_directories`:: +`DIR_HIDE_EMPTY_DIRECTORIES`::: Do not include a directory that is not tracked and is empty. -`no_gitlinks`:: +`DIR_NO_GITLINKS`::: - If set, recurse into a directory that looks like a git + If set, recurse into a directory that looks like a Git directory. Otherwise it is shown as a directory. -The result of the enumeration is left in these fields:: +The result of the enumeration is left in these fields: `entries[]`:: @@ -64,11 +67,13 @@ marked. If you to exclude files, make sure you have loaded index first. * Prepare `struct dir_struct dir` and clear it with `memset(&dir, 0, sizeof(dir))`. -* Call `add_exclude()` to add single exclude pattern, - `add_excludes_from_file()` to add patterns from a file - (e.g. `.git/info/exclude`), and/or set `dir.exclude_per_dir`. A - short-hand function `setup_standard_excludes()` can be used to set up - the standard set of exclude settings. +* To add single exclude pattern, call `add_exclude_list()` and then + `add_exclude()`. + +* To add patterns from a file (e.g. `.git/info/exclude`), call + `add_excludes_from_file()` , and/or set `dir.exclude_per_dir`. A + short-hand function `setup_standard_excludes()` can be used to set + up the standard set of exclude settings. * Set options described in the Data Structure section above. @@ -76,4 +81,6 @@ marked. If you to exclude files, make sure you have loaded index first. * Use `dir.entries[]`. +* Call `clear_directory()` when none of the contained elements are no longer in use. + (JC) diff --git a/Documentation/technical/api-gitattributes.txt b/Documentation/technical/api-gitattributes.txt index 9d97eaa9de..ce363b6305 100644 --- a/Documentation/technical/api-gitattributes.txt +++ b/Documentation/technical/api-gitattributes.txt @@ -11,27 +11,15 @@ Data Structure `struct git_attr`:: An attribute is an opaque object that is identified by its name. - Pass the name and its length to `git_attr()` function to obtain - the object of this type. The internal representation of this - structure is of no interest to the calling programs. + Pass the name to `git_attr()` function to obtain the object of + this type. The internal representation of this structure is + of no interest to the calling programs. The name of the + attribute can be retrieved by calling `git_attr_name()`. `struct git_attr_check`:: This structure represents a set of attributes to check in a call - to `git_checkattr()` function, and receives the results. - - -Calling Sequence ----------------- - -* Prepare an array of `struct git_attr_check` to define the list of - attributes you would want to check. To populate this array, you would - need to define necessary attributes by calling `git_attr()` function. - -* Call git_checkattr() to check the attributes for the path. - -* Inspect `git_attr_check` structure to see how each of the attribute in - the array is defined for the path. + to `git_check_attr()` function, and receives the results. Attribute Values @@ -57,6 +45,19 @@ If none of the above returns true, `.value` member points at a string value of the attribute for the path. +Querying Specific Attributes +---------------------------- + +* Prepare an array of `struct git_attr_check` to define the list of + attributes you would want to check. To populate this array, you would + need to define necessary attributes by calling `git_attr()` function. + +* Call `git_check_attr()` to check the attributes for the path. + +* Inspect `git_attr_check` structure to see how each of the attribute in + the array is defined for the path. + + Example ------- @@ -72,18 +73,18 @@ static void setup_check(void) { if (check[0].attr) return; /* already done */ - check[0].attr = git_attr("crlf", 4); - check[1].attr = git_attr("ident", 5); + check[0].attr = git_attr("crlf"); + check[1].attr = git_attr("ident"); } ------------ -. Call `git_checkattr()` with the prepared array of `struct git_attr_check`: +. Call `git_check_attr()` with the prepared array of `struct git_attr_check`: ------------ const char *path; setup_check(); - git_checkattr(path, ARRAY_SIZE(check), check); + git_check_attr(path, ARRAY_SIZE(check), check); ------------ . Act on `.value` member of the result, left in `check[]`: @@ -108,4 +109,20 @@ static void setup_check(void) } ------------ -(JC) + +Querying All Attributes +----------------------- + +To get the values of all attributes associated with a file: + +* Call `git_all_attrs()`, which returns an array of `git_attr_check` + structures. + +* Iterate over the `git_attr_check` array to examine the attribute + names and values. The name of the attribute described by a + `git_attr_check` object can be retrieved via + `git_attr_name(check[i].attr)`. (Please note that no items will be + returned for unset attributes, so `ATTR_UNSET()` will return false + for all returned `git_array_check` objects.) + +* Free the `git_array_check` array. diff --git a/Documentation/technical/api-history-graph.txt b/Documentation/technical/api-history-graph.txt index d6fc90ac7e..18142b6d29 100644 --- a/Documentation/technical/api-history-graph.txt +++ b/Documentation/technical/api-history-graph.txt @@ -33,11 +33,11 @@ The following utility functions are wrappers around `graph_next_line()` and They can all be called with a NULL graph argument, in which case no graph output will be printed. -* `graph_show_commit()` calls `graph_next_line()` until it returns non-zero. - This prints all graph lines up to, and including, the line containing this - commit. Output is printed to stdout. The last line printed does not contain - a terminating newline. This should not be called if the commit line has - already been printed, or it will loop forever. +* `graph_show_commit()` calls `graph_next_line()` and + `graph_is_commit_finished()` until one of them return non-zero. This prints + all graph lines up to, and including, the line containing this commit. + Output is printed to stdout. The last line printed does not contain a + terminating newline. * `graph_show_oneline()` calls `graph_next_line()` and prints the result to stdout. The line printed does not contain a terminating newline. diff --git a/Documentation/technical/api-index-skel.txt b/Documentation/technical/api-index-skel.txt index af7cc2e395..eda8c195c1 100644 --- a/Documentation/technical/api-index-skel.txt +++ b/Documentation/technical/api-index-skel.txt @@ -1,7 +1,7 @@ -GIT API Documents +Git API Documents ================= -GIT has grown a set of internal API over time. This collection +Git has grown a set of internal API over time. This collection documents them. //////////////////////////////////////////////////////////////// @@ -11,5 +11,3 @@ documents them. //////////////////////////////////////////////////////////////// // table of contents end //////////////////////////////////////////////////////////////// - -2007-11-24 diff --git a/Documentation/technical/api-parse-options.txt b/Documentation/technical/api-parse-options.txt index f6a4a361bd..32ddc1cf13 100644 --- a/Documentation/technical/api-parse-options.txt +++ b/Documentation/technical/api-parse-options.txt @@ -1,7 +1,7 @@ parse-options API ================= -The parse-options API is used to parse and massage options in git +The parse-options API is used to parse and massage options in Git and to provide a usage help with consistent look. Basics @@ -21,7 +21,7 @@ that allow to change the behavior of a command. * There are basically two forms of options: 'Short options' consist of one dash (`-`) and one alphanumeric character. - 'Long options' begin with two dashes (`\--`) and some + 'Long options' begin with two dashes (`--`) and some alphanumeric characters. * Options are case-sensitive. @@ -31,7 +31,7 @@ The parse-options API allows: * 'sticked' and 'separate form' of options with arguments. `-oArg` is sticked, `-o Arg` is separate form. - `\--option=Arg` is sticked, `\--option Arg` is separate form. + `--option=Arg` is sticked, `--option Arg` is separate form. * Long options may be 'abbreviated', as long as the abbreviation is unambiguous. @@ -39,11 +39,12 @@ The parse-options API allows: * Short options may be bundled, e.g. `-a -b` can be specified as `-ab`. * Boolean long options can be 'negated' (or 'unset') by prepending - `no-`, e.g. `\--no-abbrev` instead of `\--abbrev`. + `no-`, e.g. `--no-abbrev` instead of `--abbrev`. Conversely, + options that begin with `no-` can be 'negated' by removing it. -* Options and non-option arguments can clearly be separated using the `\--` - option, e.g. `-a -b \--option \-- \--this-is-a-file` indicates that - `\--this-is-a-file` must not be processed as an option. +* Options and non-option arguments can clearly be separated using the `--` + option, e.g. `-a -b --option -- --this-is-a-file` indicates that + `--this-is-a-file` must not be processed as an option. Steps to parse options ---------------------- @@ -75,7 +76,7 @@ before the full parser, which in turn shows the full help message. Flags are the bitwise-or of: `PARSE_OPT_KEEP_DASHDASH`:: - Keep the `\--` that usually separates options from + Keep the `--` that usually separates options from non-option arguments. `PARSE_OPT_STOP_AT_NON_OPTION`:: @@ -113,31 +114,36 @@ say `static struct option builtin_add_options[]`. There are some macros to easily define options: `OPT__ABBREV(&int_var)`:: - Add `\--abbrev[=<n>]`. + Add `--abbrev[=<n>]`. `OPT__COLOR(&int_var, description)`:: - Add `\--color[=<when>]` and `--no-color`. + Add `--color[=<when>]` and `--no-color`. `OPT__DRY_RUN(&int_var, description)`:: - Add `-n, \--dry-run`. + Add `-n, --dry-run`. `OPT__FORCE(&int_var, description)`:: - Add `-f, \--force`. + Add `-f, --force`. `OPT__QUIET(&int_var, description)`:: - Add `-q, \--quiet`. + Add `-q, --quiet`. `OPT__VERBOSE(&int_var, description)`:: - Add `-v, \--verbose`. + Add `-v, --verbose`. `OPT_GROUP(description)`:: Start an option group. `description` is a short string that describes the group or an empty string. Start the description with an upper-case letter. -`OPT_BOOLEAN(short, long, &int_var, description)`:: - Introduce a boolean option. - `int_var` is incremented on each use. +`OPT_BOOL(short, long, &int_var, description)`:: + Introduce a boolean option. `int_var` is set to one with + `--option` and set to zero with `--no-option`. + +`OPT_COUNTUP(short, long, &int_var, description)`:: + Introduce a count-up option. + `int_var` is incremented on each use of `--option`, and + reset to zero with `--no-option`. `OPT_BIT(short, long, &int_var, description, mask)`:: Introduce a boolean option. @@ -148,8 +154,9 @@ There are some macros to easily define options: If used, `int_var` is bitwise-anded with the inverted `mask`. `OPT_SET_INT(short, long, &int_var, description, integer)`:: - Introduce a boolean option. - If used, set `int_var` to `integer`. + Introduce an integer option. + `int_var` is set to `integer` with `--option`, and + reset to zero with `--no-option`. `OPT_SET_PTR(short, long, &ptr_var, description, ptr)`:: Introduce a boolean option. @@ -198,16 +205,21 @@ There are some macros to easily define options: "auto", set `int_var` to 1 if stdout is a tty or a pager, 0 otherwise. +`OPT_NOOP_NOARG(short, long)`:: + Introduce an option that has no effect and takes no arguments. + Use it to hide deprecated options that are still to be recognized + and ignored silently. + The last element of the array must be `OPT_END()`. If not stated otherwise, interpret the arguments as follows: * `short` is a character for the short option - (e.g. `{apostrophe}e{apostrophe}` for `-e`, use `0` to omit), + (e.g. `'e'` for `-e`, use `0` to omit), * `long` is a string for the long option - (e.g. `"example"` for `\--example`, use `NULL` to omit), + (e.g. `"example"` for `--example`, use `NULL` to omit), * `int_var` is an integer variable, @@ -231,10 +243,10 @@ The function must be defined in this form: The callback mechanism is as follows: * Inside `func`, the only interesting member of the structure - given by `opt` is the void pointer `opt\->value`. - `\*opt\->value` will be the value that is saved into `var`, if you + given by `opt` is the void pointer `opt->value`. + `*opt->value` will be the value that is saved into `var`, if you use `OPT_CALLBACK()`. - For example, do `*(unsigned long *)opt\->value = 42;` to get 42 + For example, do `*(unsigned long *)opt->value = 42;` to get 42 into an `unsigned long` variable. * Return value `0` indicates success and non-zero return diff --git a/Documentation/technical/api-remote.txt b/Documentation/technical/api-remote.txt index c54b17db69..4be87768f6 100644 --- a/Documentation/technical/api-remote.txt +++ b/Documentation/technical/api-remote.txt @@ -3,7 +3,7 @@ Remotes configuration API The API in remote.h gives access to the configuration related to remotes. It handles all three configuration mechanisms historically -and currently used by git, and presents the information in a uniform +and currently used by Git, and presents the information in a uniform fashion. Note that the code also handles plain URLs without any configuration, giving them just the default information. @@ -45,7 +45,7 @@ struct remote `receivepack`, `uploadpack`:: The configured helper programs to run on the remote side, for - git-native protocols. + Git-native protocols. `http_proxy`:: diff --git a/Documentation/technical/api-revision-walking.txt b/Documentation/technical/api-revision-walking.txt index 996da0503a..b7d0d9a8a7 100644 --- a/Documentation/technical/api-revision-walking.txt +++ b/Documentation/technical/api-revision-walking.txt @@ -56,6 +56,11 @@ function. returning a `struct commit *` each time you call it. The end of the revision list is indicated by returning a NULL pointer. +`reset_revision_walk`:: + + Reset the flags used by the revision walking api. You can use + this to do multiple sequencial revision walks. + Data structures --------------- diff --git a/Documentation/technical/api-run-command.txt b/Documentation/technical/api-run-command.txt index f18b4f4817..5d7d7f2d32 100644 --- a/Documentation/technical/api-run-command.txt +++ b/Documentation/technical/api-run-command.txt @@ -55,10 +55,8 @@ The functions above do the following: non-zero. . If the program terminated due to a signal, then the return value is the - signal number - 128, ie. it is negative and so indicates an unusual - condition; a diagnostic is printed. This return value can be passed to - exit(2), which will report the same code to the parent process that a - POSIX shell's $? would report for a program that died from the signal. + signal number + 128, ie. the same value that a POSIX shell's $? would + report. A diagnostic is printed. `start_async`:: diff --git a/Documentation/technical/api-sha1-array.txt b/Documentation/technical/api-sha1-array.txt new file mode 100644 index 0000000000..45d1c517cd --- /dev/null +++ b/Documentation/technical/api-sha1-array.txt @@ -0,0 +1,76 @@ +sha1-array API +============== + +The sha1-array API provides storage and manipulation of sets of SHA1 +identifiers. The emphasis is on storage and processing efficiency, +making them suitable for large lists. Note that the ordering of items is +not preserved over some operations. + +Data Structures +--------------- + +`struct sha1_array`:: + + A single array of SHA1 hashes. This should be initialized by + assignment from `SHA1_ARRAY_INIT`. The `sha1` member contains + the actual data. The `nr` member contains the number of items in + the set. The `alloc` and `sorted` members are used internally, + and should not be needed by API callers. + +Functions +--------- + +`sha1_array_append`:: + Add an item to the set. The sha1 will be placed at the end of + the array (but note that some operations below may lose this + ordering). + +`sha1_array_lookup`:: + Perform a binary search of the array for a specific sha1. + If found, returns the offset (in number of elements) of the + sha1. If not found, returns a negative integer. If the array is + not sorted, this function has the side effect of sorting it. + +`sha1_array_clear`:: + Free all memory associated with the array and return it to the + initial, empty state. + +`sha1_array_for_each_unique`:: + Efficiently iterate over each unique element of the list, + executing the callback function for each one. If the array is + not sorted, this function has the side effect of sorting it. + +Examples +-------- + +----------------------------------------- +void print_callback(const unsigned char sha1[20], + void *data) +{ + printf("%s\n", sha1_to_hex(sha1)); +} + +void some_func(void) +{ + struct sha1_array hashes = SHA1_ARRAY_INIT; + unsigned char sha1[20]; + + /* Read objects into our set */ + while (read_object_from_stdin(sha1)) + sha1_array_append(&hashes, sha1); + + /* Check if some objects are in our set */ + while (read_object_from_stdin(sha1)) { + if (sha1_array_lookup(&hashes, sha1) >= 0) + printf("it's in there!\n"); + + /* + * Print the unique set of objects. We could also have + * avoided adding duplicate objects in the first place, + * but we would end up re-sorting the array repeatedly. + * Instead, this will sort once and then skip duplicates + * in linear time. + */ + sha1_array_for_each_unique(&hashes, print_callback, NULL); +} +----------------------------------------- diff --git a/Documentation/technical/api-strbuf.txt b/Documentation/technical/api-strbuf.txt index afe2759951..2c59cb2259 100644 --- a/Documentation/technical/api-strbuf.txt +++ b/Documentation/technical/api-strbuf.txt @@ -156,6 +156,11 @@ then they will free() it. Remove the bytes between `pos..pos+len` and replace it with the given data. +`strbuf_add_commented_lines`:: + + Add a NUL-terminated string to the buffer. Each line will be prepended + by a comment character and a blank. + `strbuf_add`:: Add data of given length to the buffer. @@ -229,6 +234,11 @@ which can be used by the programmer of the callback as she sees fit. Add a formatted string to the buffer. +`strbuf_commented_addf`:: + + Add a formatted string prepended by a comment character and a + blank to the buffer. + `strbuf_fread`:: Read a given size of data from a FILE* pointer to the buffer. @@ -255,14 +265,46 @@ same behaviour as well. `strbuf_getline`:: - Read a line from a FILE* pointer. The second argument specifies the line + Read a line from a FILE *, overwriting the existing contents + of the strbuf. The second argument specifies the line terminator character, typically `'\n'`. + Reading stops after the terminator or at EOF. The terminator + is removed from the buffer before returning. Returns 0 unless + there was nothing left before EOF, in which case it returns `EOF`. + +`strbuf_getwholeline`:: + + Like `strbuf_getline`, but keeps the trailing terminator (if + any) in the buffer. + +`strbuf_getwholeline_fd`:: + + Like `strbuf_getwholeline`, but operates on a file descriptor. + It reads one character at a time, so it is very slow. Do not + use it unless you need the correct position in the file + descriptor. `stripspace`:: Strip whitespace from a buffer. The second parameter controls if comments are considered contents to be removed or not. +`strbuf_split_buf`:: +`strbuf_split_str`:: +`strbuf_split_max`:: +`strbuf_split`:: + + Split a string or strbuf into a list of strbufs at a specified + terminator character. The returned substrings include the + terminator characters. Some of these functions take a `max` + parameter, which, if positive, limits the output to that + number of substrings. + +`strbuf_list_free`:: + + Free a list of strbufs (for example, the return values of the + `strbuf_split()` functions). + `launch_editor`:: Launch the user preferred editor to edit a file and fill the buffer diff --git a/Documentation/technical/api-string-list.txt b/Documentation/technical/api-string-list.txt index 3f575bdcff..20be348834 100644 --- a/Documentation/technical/api-string-list.txt +++ b/Documentation/technical/api-string-list.txt @@ -1,8 +1,9 @@ string-list API =============== -The string_list API offers a data structure and functions to handle sorted -and unsorted string lists. +The string_list API offers a data structure and functions to handle +sorted and unsorted string lists. A "sorted" list is one whose +entries are sorted by string value in `strcmp()` order. The 'string_list' struct used to be called 'path_list', but was renamed because it is not specific to paths. @@ -20,8 +21,9 @@ If you need something advanced, you can manually malloc() the `items` member (you need this if you add things later) and you should set the `nr` and `alloc` members in that case, too. -. Adds new items to the list, using `string_list_append` or - `string_list_insert`. +. Adds new items to the list, using `string_list_append`, + `string_list_append_nodup`, `string_list_insert`, + `string_list_split`, and/or `string_list_split_in_place`. . Can check if a string is in the list using `string_list_has_string` or `unsorted_string_list_has_string` and get it from the list using @@ -29,15 +31,24 @@ member (you need this if you add things later) and you should set the . Can sort an unsorted list using `sort_string_list`. +. Can remove duplicate items from a sorted list using + `string_list_remove_duplicates`. + +. Can remove individual items of an unsorted list using + `unsorted_string_list_delete_item`. + +. Can remove items not matching a criterion from a sorted or unsorted + list using `filter_string_list`, or remove empty strings using + `string_list_remove_empty_items`. + . Finally it should free the list using `string_list_clear`. Example: ---- -struct string_list list; +struct string_list list = STRING_LIST_INIT_NODUP; int i; -memset(&list, 0, sizeof(struct string_list)); string_list_append(&list, "foo"); string_list_append(&list, "bar"); for (i = 0; i < list.nr; i++) @@ -57,6 +68,20 @@ Functions * General ones (works with sorted and unsorted lists as well) +`filter_string_list`:: + + Apply a function to each item in a list, retaining only the + items for which the function returns true. If free_util is + true, call free() on the util members of any items that have + to be deleted. Preserve the order of the items that are + retained. + +`string_list_remove_empty_items`:: + + Remove any empty strings from the list. If free_util is true, + call free() on the util members of any items that have to be + deleted. Preserve the order of the items that are retained. + `print_string_list`:: Dump a string_list to stdout, useful mainly for debugging purposes. It @@ -80,7 +105,9 @@ Functions Insert a new element to the string_list. The returned pointer can be handy if you want to write something to the `util` pointer of the - string_list_item containing the just added string. + string_list_item containing the just added string. If the given + string already exists the insertion will be skipped and the + pointer to the existing item returned. + Since this function uses xrealloc() (which die()s if it fails) if the list needs to grow, it is safe not to check the pointer. I.e. you may @@ -91,15 +118,32 @@ write `string_list_insert(...)->util = ...;`. Look up a given string in the string_list, returning the containing string_list_item. If the string is not found, NULL is returned. +`string_list_remove_duplicates`:: + + Remove all but the first of consecutive entries that have the + same string value. If free_util is true, call free() on the + util members of any items that have to be deleted. + * Functions for unsorted lists only `string_list_append`:: - Append a new string to the end of the string_list. + Append a new string to the end of the string_list. If + `strdup_string` is set, then the string argument is copied; + otherwise the new `string_list_entry` refers to the input + string. + +`string_list_append_nodup`:: + + Append a new string to the end of the string_list. The new + `string_list_entry` always refers to the input string, even if + `strdup_string` is set. This function can be used to hand + ownership of a malloc()ed string to a `string_list` that has + `strdup_string` set. `sort_string_list`:: - Make an unsorted list sorted. + Sort the list's entries by string value in `strcmp()` order. `unsorted_string_list_has_string`:: @@ -112,6 +156,32 @@ write `string_list_insert(...)->util = ...;`. The above two functions need to look through all items, as opposed to their counterpart for sorted lists, which performs a binary search. +`unsorted_string_list_delete_item`:: + + Remove an item from a string_list. The `string` pointer of the items + will be freed in case the `strdup_strings` member of the string_list + is set. The third parameter controls if the `util` pointer of the + items should be freed or not. + +`string_list_split`:: +`string_list_split_in_place`:: + + Split a string into substrings on a delimiter character and + append the substrings to a `string_list`. If `maxsplit` is + non-negative, then split at most `maxsplit` times. Return the + number of substrings appended to the list. ++ +`string_list_split` requires a `string_list` that has `strdup_strings` +set to true; it leaves the input string untouched and makes copies of +the substrings in newly-allocated memory. +`string_list_split_in_place` requires a `string_list` that has +`strdup_strings` set to false; it splits the input string in place, +overwriting the delimiter characters with NULs and creating new +string_list_items that point into the original string (the original +string must therefore not be modified or freed while the `string_list` +is in use). + + Data structures --------------- diff --git a/Documentation/technical/index-format.txt b/Documentation/technical/index-format.txt index 8930b3fabc..0810251f5a 100644 --- a/Documentation/technical/index-format.txt +++ b/Documentation/technical/index-format.txt @@ -1,7 +1,7 @@ -GIT index format +Git index format ================ -= The git index file has the following format +== The Git index file has the following format All binary numbers are in network byte order. Version 2 is described here unless stated otherwise. @@ -12,7 +12,7 @@ GIT index format The signature is { 'D', 'I', 'R', 'C' } (stands for "dircache") 4-byte version number: - The current supported versions are 2 and 3. + The current supported versions are 2, 3 and 4. 32-bit number of index entries. @@ -21,9 +21,9 @@ GIT index format - Extensions Extensions are identified by signature. Optional extensions can - be ignored if GIT does not understand them. + be ignored if Git does not understand them. - GIT currently supports cached tree and resolve undo extensions. + Git currently supports cached tree and resolve undo extensions. 4-byte extension signature. If the first byte is 'A'..'Z' the extension is optional and can be ignored. @@ -93,8 +93,8 @@ GIT index format 12-bit name length if the length is less than 0xFFF; otherwise 0xFFF is stored in this field. - (Version 3) A 16-bit field, only applicable if the "extended flag" - above is 1, split into (high to low bits). + (Version 3 or later) A 16-bit field, only applicable if the + "extended flag" above is 1, split into (high to low bits). 1-bit reserved for future @@ -113,9 +113,22 @@ GIT index format are encoded in 7-bit ASCII and the encoding cannot contain a NUL byte (iow, this is a UNIX pathname). + (Version 4) In version 4, the entry path name is prefix-compressed + relative to the path name for the previous entry (the very first + entry is encoded as if the path name for the previous entry is an + empty string). At the beginning of an entry, an integer N in the + variable width encoding (the same encoding as the offset is encoded + for OFS_DELTA pack entries; see pack-format.txt) is stored, followed + by a NUL-terminated string S. Removing N bytes from the end of the + path name for the previous entry, and replacing it with the string S + yields the path name for this entry. + 1-8 nul bytes as necessary to pad the entry to a multiple of eight bytes while keeping the name NUL-terminated. + (Version 4) In version 4, the padding after the pathname does not + exist. + == Extensions === Cached tree @@ -148,8 +161,9 @@ GIT index format this span of index as a tree. An entry can be in an invalidated state and is represented by having - -1 in the entry_count field. In this case, there is no object name - and the next entry starts immediately after the newline. + a negative number in the entry_count field. In this case, there is no + object name and the next entry starts immediately after the newline. + When writing an invalid entry, -1 should always be used as entry_count. The entries are written out in the top-down, depth-first order. The first entry represents the root level of the repository, followed by the diff --git a/Documentation/technical/pack-format.txt b/Documentation/technical/pack-format.txt index 1803e64e46..0e37ec9de5 100644 --- a/Documentation/technical/pack-format.txt +++ b/Documentation/technical/pack-format.txt @@ -1,7 +1,7 @@ -GIT pack format +Git pack format =============== -= pack-*.pack files have the following format: +== pack-*.pack files have the following format: - A header appears at the beginning and consists of the following: @@ -9,7 +9,7 @@ GIT pack format The signature is: {'P', 'A', 'C', 'K'} 4-byte version number (network byte order): - GIT currently accepts version number 2 or 3 but + Git currently accepts version number 2 or 3 but generates version 2 only. 4-byte number of objects contained in the pack (network byte order) @@ -34,7 +34,7 @@ GIT pack format - The trailer records 20-byte SHA1 checksum of all of the above. -= Original (version 1) pack-*.idx files have the following format: +== Original (version 1) pack-*.idx files have the following format: - The header consists of 256 4-byte network byte order integers. N-th entry of this table records the number of @@ -123,8 +123,8 @@ Pack file entry: <+ -= Version 2 pack-*.idx files support packs larger than 4 GiB, and - have some other reorganizations. They have the format: +== Version 2 pack-*.idx files support packs larger than 4 GiB, and + have some other reorganizations. They have the format: - A 4-byte magic number '\377tOc' which is an unreasonable fanout[0] value. diff --git a/Documentation/technical/pack-heuristics.txt b/Documentation/technical/pack-heuristics.txt index 103eb5d989..dbdf7ba9c8 100644 --- a/Documentation/technical/pack-heuristics.txt +++ b/Documentation/technical/pack-heuristics.txt @@ -5,11 +5,11 @@ Where do I go to learn the details - of git's packing heuristics? + of Git's packing heuristics? Be careful what you ask! -Followers of the git, please open the git IRC Log and turn to +Followers of the Git, please open the Git IRC Log and turn to February 10, 2006. It's a rare occasion, and we are joined by the King Git Himself, @@ -19,7 +19,7 @@ and seeks enlightenment. Others are present, but silent. Let's listen in! <njs`> Oh, here's a really stupid question -- where do I go to - learn the details of git's packing heuristics? google avails + learn the details of Git's packing heuristics? google avails me not, reading the source didn't help a lot, and wading through the whole mailing list seems less efficient than any of that. @@ -37,7 +37,7 @@ Ah! Modesty after all. <linus> njs, I don't think the docs exist. That's something where I don't think anybody else than me even really got involved. - Most of the rest of git others have been busy with (especially + Most of the rest of Git others have been busy with (especially Junio), but packing nobody touched after I did it. It's cryptic, yet vague. Linus in style for sure. Wise men @@ -57,7 +57,7 @@ Bait... And switch. That ought to do it! - <linus> Remember: git really doesn't follow files. So what it does is + <linus> Remember: Git really doesn't follow files. So what it does is - generate a list of all objects - sort the list according to magic heuristics - walk the list, using a sliding window, seeing if an object @@ -382,7 +382,7 @@ The 'net never forgets, so that should be good until the end of time. <njs`> (if only it happened more...) <linus> Anyway, the pack-file could easily be denser still, but - because it's used both for streaming (the git protocol) and + because it's used both for streaming (the Git protocol) and for on-disk, it has a few pessimizations. Actually, it is a made-up word. But it is a made-up word being @@ -432,12 +432,12 @@ Gasp! OK, saved. That's a fair Engineering trade off. Close call! In fact, Linus reflects on some Basic Engineering Fundamentals, design options, etc. - <linus> More importantly, they allow git to still _conceptually_ + <linus> More importantly, they allow Git to still _conceptually_ never deal with deltas at all, and be a "whole object" store. Which has some problems (we discussed bad huge-file - behaviour on the git lists the other day), but it does mean - that the basic git concepts are really really simple and + behaviour on the Git lists the other day), but it does mean + that the basic Git concepts are really really simple and straightforward. It's all been quite stable. @@ -461,6 +461,6 @@ Nuff said. <njs`> :-) <njs`> appreciate the infodump, I really was failing to find the - details on git packs :-) + details on Git packs :-) And now you know the rest of the story. diff --git a/Documentation/technical/pack-protocol.txt b/Documentation/technical/pack-protocol.txt index a7004c63e7..f1a51edf47 100644 --- a/Documentation/technical/pack-protocol.txt +++ b/Documentation/technical/pack-protocol.txt @@ -60,6 +60,13 @@ process on the server side over the Git protocol is this: "0039git-upload-pack /schacon/gitbook.git\0host=example.com\0" | nc -v example.com 9418 +If the server refuses the request for some reasons, it could abort +gracefully with an error message. + +---- + error-line = PKT-LINE("ERR" SP explanation-text) +---- + SSH Transport ------------- @@ -110,7 +117,7 @@ A few things to remember here: - The repository path is always quoted with single quotes. Fetching Data From a Server -=========================== +--------------------------- When one Git repository wants to get data that a second repository has, the first can 'fetch' from the second. This operation determines @@ -127,7 +134,8 @@ with the object name that each reference currently points to. $ echo -e -n "0039git-upload-pack /schacon/gitbook.git\0host=example.com\0" | nc -v example.com 9418 - 00887217a7c7e582c46cec22a130adf4b9d7d950fba0 HEAD\0multi_ack thin-pack side-band side-band-64k ofs-delta shallow no-progress include-tag + 00887217a7c7e582c46cec22a130adf4b9d7d950fba0 HEAD\0multi_ack thin-pack + side-band side-band-64k ofs-delta shallow no-progress include-tag 00441d3fcd5ced445d1abc402225c0b8a1299641f497 refs/heads/integration 003f7217a7c7e582c46cec22a130adf4b9d7d950fba0 refs/heads/master 003cb88d2441cac0977faf98efc80305012112238d9d refs/tags/v0.9 @@ -252,8 +260,10 @@ a positive depth, this step is skipped. ---- If the client has requested a positive depth, the server will compute -the set of commits which are no deeper than the desired depth, starting -at the client's wants. The server writes 'shallow' lines for each +the set of commits which are no deeper than the desired depth. The set +of commits start at the client's wants. + +The server writes 'shallow' lines for each commit whose parents will not be sent as a result. The server writes an 'unshallow' line for each commit which the client has indicated is shallow, but is no longer shallow at the currently requested depth @@ -344,7 +354,7 @@ Then the server will start sending its packfile data. A simple clone may look like this (with no 'have' lines): ---- - C: 0054want 74730d410fcb6603ace96f1dc55ea6196122532d\0multi_ack \ + C: 0054want 74730d410fcb6603ace96f1dc55ea6196122532d multi_ack \ side-band-64k ofs-delta\n C: 0032want 7d1665144a3a975c05f1f43902ddaf084e784dbe\n C: 0032want 5a3f6be755bbb7deae50065988cbfa1ffa9ab68a\n @@ -360,7 +370,7 @@ A simple clone may look like this (with no 'have' lines): An incremental update (fetch) response might look like this: ---- - C: 0054want 74730d410fcb6603ace96f1dc55ea6196122532d\0multi_ack \ + C: 0054want 74730d410fcb6603ace96f1dc55ea6196122532d multi_ack \ side-band-64k ofs-delta\n C: 0032want 7d1665144a3a975c05f1f43902ddaf084e784dbe\n C: 0032want 5a3f6be755bbb7deae50065988cbfa1ffa9ab68a\n @@ -412,7 +422,7 @@ entire packfile without multiplexing. Pushing Data To a Server -======================== +------------------------ Pushing data to a server will invoke the 'receive-pack' process on the server, which will allow the client to tell it which references it should diff --git a/Documentation/technical/protocol-common.txt b/Documentation/technical/protocol-common.txt index d30a1b9510..fb7ff084f8 100644 --- a/Documentation/technical/protocol-common.txt +++ b/Documentation/technical/protocol-common.txt @@ -36,7 +36,7 @@ More specifically, they: . They cannot have ASCII control characters (i.e. bytes whose values are lower than \040, or \177 `DEL`), space, tilde `~`, - caret `{caret}`, colon `:`, question-mark `?`, asterisk `*`, + caret `^`, colon `:`, question-mark `?`, asterisk `*`, or open bracket `[` anywhere. . They cannot end with a slash `/` nor a dot `.`. diff --git a/Documentation/technical/racy-git.txt b/Documentation/technical/racy-git.txt index 53aa0c82c2..6dc82ca5a8 100644 --- a/Documentation/technical/racy-git.txt +++ b/Documentation/technical/racy-git.txt @@ -1,21 +1,21 @@ -Use of index and Racy git problem +Use of index and Racy Git problem ================================= Background ---------- -The index is one of the most important data structures in git. +The index is one of the most important data structures in Git. It represents a virtual working tree state by recording list of paths and their object names and serves as a staging area to write out the next tree object to be committed. The state is "virtual" in the sense that it does not necessarily have to, and often does not, match the files in the working tree. -There are cases git needs to examine the differences between the +There are cases Git needs to examine the differences between the virtual working tree state in the index and the files in the working tree. The most obvious case is when the user asks `git diff` (or its low level implementation, `git diff-files`) or -`git-ls-files --modified`. In addition, git internally checks +`git-ls-files --modified`. In addition, Git internally checks if the files in the working tree are different from what are recorded in the index to avoid stomping on local changes in them during patch application, switching branches, and merging. @@ -24,16 +24,16 @@ In order to speed up this comparison between the files in the working tree and the index entries, the index entries record the information obtained from the filesystem via `lstat(2)` system call when they were last updated. When checking if they differ, -git first runs `lstat(2)` on the files and compares the result +Git first runs `lstat(2)` on the files and compares the result with this information (this is what was originally done by the `ce_match_stat()` function, but the current code does it in `ce_match_stat_basic()` function). If some of these "cached -stat information" fields do not match, git can tell that the +stat information" fields do not match, Git can tell that the files are modified without even looking at their contents. Note: not all members in `struct stat` obtained via `lstat(2)` are used for this comparison. For example, `st_atime` obviously -is not useful. Currently, git compares the file type (regular +is not useful. Currently, Git compares the file type (regular files vs symbolic links) and executable bits (only for regular files) from `st_mode` member, `st_mtime` and `st_ctime` timestamps, `st_uid`, `st_gid`, `st_ino`, and `st_size` members. @@ -49,7 +49,7 @@ of git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git ([PATCH] Sync in core time granuality with filesystems, 2005-01-04). -Racy git +Racy Git -------- There is one slight problem with the optimization based on the @@ -67,13 +67,13 @@ timestamp does not change, after this sequence, the cached stat information the index entry records still exactly match what you would see in the filesystem, even though the file `foo` is now different. -This way, git can incorrectly think files in the working tree +This way, Git can incorrectly think files in the working tree are unmodified even though they actually are. This is called -the "racy git" problem (discovered by Pasky), and the entries +the "racy Git" problem (discovered by Pasky), and the entries that appear clean when they may not be because of this problem are called "racily clean". -To avoid this problem, git does two things: +To avoid this problem, Git does two things: . When the cached stat information says the file has not been modified, and the `st_mtime` is the same as (or newer than) @@ -116,7 +116,7 @@ timestamp comparison check done with the former logic anymore. The latter makes sure that the cached stat information for `foo` would never match with the file in the working tree, so later checks by `ce_match_stat_basic()` would report that the index entry -does not match the file and git does not have to fall back on more +does not match the file and Git does not have to fall back on more expensive `ce_modified_check_fs()`. @@ -159,7 +159,7 @@ of the cached stat information. Avoiding runtime penalty ------------------------ -In order to avoid the above runtime penalty, post 1.4.2 git used +In order to avoid the above runtime penalty, post 1.4.2 Git used to have a code that made sure the index file got timestamp newer than the youngest files in the index when there are many young files with the same timestamp as the diff --git a/Documentation/technical/send-pack-pipeline.txt b/Documentation/technical/send-pack-pipeline.txt index 681efe4219..9b5a0bc186 100644 --- a/Documentation/technical/send-pack-pipeline.txt +++ b/Documentation/technical/send-pack-pipeline.txt @@ -1,5 +1,5 @@ -git-send-pack -============= +Git-send-pack internals +======================= Overall operation ----------------- diff --git a/Documentation/technical/shallow.txt b/Documentation/technical/shallow.txt index 559263af48..ea2f69faf5 100644 --- a/Documentation/technical/shallow.txt +++ b/Documentation/technical/shallow.txt @@ -1,6 +1,12 @@ -Def.: Shallow commits do have parents, but not in the shallow +Shallow commits +=============== + +.Definition +********************************************************* +Shallow commits do have parents, but not in the shallow repo, and therefore grafts are introduced pretending that these commits have no parents. +********************************************************* The basic idea is to write the SHA1s of shallow commits into $GIT_DIR/shallow, and handle its contents like the contents @@ -47,3 +53,6 @@ It also writes an appropriate $GIT_DIR/shallow. You can deepen a shallow repository with "git-fetch --depth 20 repo branch", which will fetch branch from repo, but stop at depth 20, updating $GIT_DIR/shallow. + +The special depth 2147483647 (or 0x7fffffff, the largest positive +number a signed 32-bit integer can contain) means infinite depth. diff --git a/Documentation/technical/trivial-merge.txt b/Documentation/technical/trivial-merge.txt index 24c84100b0..c79d4a7c47 100644 --- a/Documentation/technical/trivial-merge.txt +++ b/Documentation/technical/trivial-merge.txt @@ -74,24 +74,24 @@ For multiple ancestors, a '+' means that this case applies even if only one ancestor or remote fits; a '^' means all of the ancestors must be the same. -case ancest head remote result ----------------------------------------- -1 (empty)+ (empty) (empty) (empty) -2ALT (empty)+ *empty* remote remote -2 (empty)^ (empty) remote no merge -3ALT (empty)+ head *empty* head -3 (empty)^ head (empty) no merge -4 (empty)^ head remote no merge -5ALT * head head head -6 ancest+ (empty) (empty) no merge -8 ancest^ (empty) ancest no merge -7 ancest+ (empty) remote no merge -10 ancest^ ancest (empty) no merge -9 ancest+ head (empty) no merge -16 anc1/anc2 anc1 anc2 no merge -13 ancest+ head ancest head -14 ancest+ ancest remote remote -11 ancest+ head remote no merge + case ancest head remote result + ---------------------------------------- + 1 (empty)+ (empty) (empty) (empty) + 2ALT (empty)+ *empty* remote remote + 2 (empty)^ (empty) remote no merge + 3ALT (empty)+ head *empty* head + 3 (empty)^ head (empty) no merge + 4 (empty)^ head remote no merge + 5ALT * head head head + 6 ancest+ (empty) (empty) no merge + 8 ancest^ (empty) ancest no merge + 7 ancest+ (empty) remote no merge + 10 ancest^ ancest (empty) no merge + 9 ancest+ head (empty) no merge + 16 anc1/anc2 anc1 anc2 no merge + 13 ancest+ head ancest head + 14 ancest+ ancest remote remote + 11 ancest+ head remote no merge Only #2ALT and #3ALT use *empty*, because these are the only cases where there can be conflicts that didn't exist before. Note that we |