diff options
Diffstat (limited to 'Documentation/technical')
| -rw-r--r-- | Documentation/technical/api-builtin.txt | 15 | ||||
| -rw-r--r-- | Documentation/technical/api-parse-options.txt | 204 | ||||
| -rw-r--r-- | Documentation/technical/api-path-list.txt | 125 | ||||
| -rw-r--r-- | Documentation/technical/api-run-command.txt | 6 |
4 files changed, 336 insertions, 14 deletions
diff --git a/Documentation/technical/api-builtin.txt b/Documentation/technical/api-builtin.txt index 52cdb4c520..7ede1e64e5 100644 --- a/Documentation/technical/api-builtin.txt +++ b/Documentation/technical/api-builtin.txt @@ -4,7 +4,7 @@ builtin API Adding a new built-in --------------------- -There are 4 things to do to add a bulit-in command implementation to +There are 4 things to do to add a built-in command implementation to git: . Define the implementation of the built-in command `foo` with @@ -18,8 +18,8 @@ git: defined in `git.c`. The entry should look like: { "foo", cmd_foo, <options> }, - - where options is the bitwise-or of: ++ +where options is the bitwise-or of: `RUN_SETUP`:: @@ -33,6 +33,12 @@ git: If the standard output is connected to a tty, spawn a pager and feed our output to it. +`NEED_WORK_TREE`:: + + Make sure there is a work tree, i.e. the command cannot act + on bare repositories. + This makes only sense when `RUN_SETUP` is also set. + . Add `builtin-foo.o` to `BUILTIN_OBJS` in `Makefile`. Additionally, if `foo` is a new command, there are 3 more things to do: @@ -41,8 +47,7 @@ Additionally, if `foo` is a new command, there are 3 more things to do: . Write documentation in `Documentation/git-foo.txt`. -. Add an entry for `git-foo` to the list at the end of - `Documentation/cmd-list.perl`. +. Add an entry for `git-foo` to `command-list.txt`. How a built-in is called diff --git a/Documentation/technical/api-parse-options.txt b/Documentation/technical/api-parse-options.txt index b7cda94f54..539863b1f9 100644 --- a/Documentation/technical/api-parse-options.txt +++ b/Documentation/technical/api-parse-options.txt @@ -1,6 +1,206 @@ parse-options API ================= -Talk about <parse-options.h> +The parse-options API is used to parse and massage options in git +and to provide a usage help with consistent look. -(Pierre) +Basics +------ + +The argument vector `argv[]` may usually contain mandatory or optional +'non-option arguments', e.g. a filename or a branch, and 'options'. +Options are optional arguments that start with a dash and +that allow to change the behavior of a command. + +* There are basically three types of options: + 'boolean' options, + options with (mandatory) 'arguments' and + options with 'optional arguments' + (i.e. a boolean option that can be adjusted). + +* 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 + alphanumeric characters. + +* Options are case-sensitive. + Please define 'lower-case long options' only. + +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. + +* Long options may be 'abbreviated', as long as the abbreviation + is unambiguous. + +* 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`. + +* 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 +---------------------- + +. `#include "parse-options.h"` + +. define a NULL-terminated + `static const char * const builtin_foo_usage[]` array + containing alternative usage strings + +. define `builtin_foo_options` array as described below + in section 'Data Structure'. + +. in `cmd_foo(int argc, const char **argv, const char *prefix)` + call + + argc = parse_options(argc, argv, builtin_foo_options, builtin_foo_usage, flags); ++ +`parse_options()` will filter out the processed options of `argv[]` and leave the +non-option arguments in `argv[]`. +`argc` is updated appropriately because of the assignment. ++ +Flags are the bitwise-or of: + +`PARSE_OPT_KEEP_DASHDASH`:: + Keep the `\--` that usually separates options from + non-option arguments. + +`PARSE_OPT_STOP_AT_NON_OPTION`:: + Usually the whole argument vector is massaged and reordered. + Using this flag, processing is stopped at the first non-option + argument. + +Data Structure +-------------- + +The main data structure is an array of the `option` struct, +say `static struct option builtin_add_options[]`. +There are some macros to easily define options: + +`OPT__ABBREV(&int_var)`:: + Add `\--abbrev[=<n>]`. + +`OPT__DRY_RUN(&int_var)`:: + Add `-n, \--dry-run`. + +`OPT__QUIET(&int_var)`:: + Add `-q, \--quiet`. + +`OPT__VERBOSE(&int_var)`:: + 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_BIT(short, long, &int_var, description, mask)`:: + Introduce a boolean option. + If used, `int_var` is bitwise-ored with `mask`. + +`OPT_SET_INT(short, long, &int_var, description, integer)`:: + Introduce a boolean option. + If used, set `int_var` to `integer`. + +`OPT_SET_PTR(short, long, &ptr_var, description, ptr)`:: + Introduce a boolean option. + If used, set `ptr_var` to `ptr`. + +`OPT_STRING(short, long, &str_var, arg_str, description)`:: + Introduce an option with string argument. + The string argument is put into `str_var`. + +`OPT_INTEGER(short, long, &int_var, description)`:: + Introduce an option with integer argument. + The integer is put into `int_var`. + +`OPT_DATE(short, long, &int_var, description)`:: + Introduce an option with date argument, see `approxidate()`. + The timestamp is put into `int_var`. + +`OPT_CALLBACK(short, long, &var, arg_str, description, func_ptr)`:: + Introduce an option with argument. + The argument will be fed into the function given by `func_ptr` + and the result will be put into `var`. + See 'Option Callbacks' below for a more elaborate description. + +`OPT_ARGUMENT(long, description)`:: + Introduce a long-option argument that will be kept in `argv[]`. + + +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. `\'e\'` for `-e`, use `0` to omit), + +* `long` is a string for the long option + (e.g. `"example"` for `\--example`, use `NULL` to omit), + +* `int_var` is an integer variable, + +* `str_var` is a string variable (`char *`), + +* `arg_str` is the string that is shown as argument + (e.g. `"branch"` will result in `<branch>`). + If set to `NULL`, three dots (`...`) will be displayed. + +* `description` is a short string to describe the effect of the option. + It shall begin with a lower-case letter and a full stop (`.`) shall be + omitted at the end. + +Option Callbacks +---------------- + +The function must be defined in this form: + + int func(const struct option *opt, const char *arg, int unset) + +The callback mechanism is as follows: + +* Inside `funct`, 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 + use `OPT_CALLBACK()`. + 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 + value will invoke `usage_with_options()` and, thus, die. + +* If the user negates the option, `arg` is `NULL` and `unset` is 1. + +Sophisticated option parsing +---------------------------- + +If you need, for example, option callbacks with optional arguments +or without arguments at all, or if you need other special cases, +that are not handled by the macros above, you need to specify the +members of the `option` structure manually. + +This is not covered in this document, but well documented +in `parse-options.h` itself. + +Examples +-------- + +See `test-parse-options.c` and +`builtin-add.c`, +`builtin-clone.c`, +`builtin-commit.c`, +`builtin-fetch.c`, +`builtin-fsck.c`, +`builtin-rm.c` +for real-world examples. diff --git a/Documentation/technical/api-path-list.txt b/Documentation/technical/api-path-list.txt index d077683171..9dbedd0a67 100644 --- a/Documentation/technical/api-path-list.txt +++ b/Documentation/technical/api-path-list.txt @@ -1,9 +1,126 @@ path-list API ============= -Talk about <path-list.h>, things like +The path_list API offers a data structure and functions to handle sorted +and unsorted string lists. -* it is not just paths but strings in general; -* the calling sequence. +The name is a bit misleading, a path_list may store not only paths but +strings in general. -(Dscho) +The caller: + +. Allocates and clears a `struct path_list` variable. + +. Initializes the members. You might want to set the flag `strdup_paths` + if the strings should be strdup()ed. For example, this is necessary + when you add something like git_path("..."), since that function returns + a static buffer that will change with the next call to git_path(). ++ +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 `path_list_append` or `path_list_insert`. + +. Can check if a string is in the list using `path_list_has_path` or + `unsorted_path_list_has_path` and get it from the list using + `path_list_lookup` for sorted lists. + +. Can sort an unsorted list using `sort_path_list`. + +. Finally it should free the list using `path_list_clear`. + +Example: + +---- +struct path_list list; +int i; + +memset(&list, 0, sizeof(struct path_list)); +path_list_append("foo", &list); +path_list_append("bar", &list); +for (i = 0; i < list.nr; i++) + printf("%s\n", list.items[i].path) +---- + +NOTE: It is more efficient to build an unsorted list and sort it +afterwards, instead of building a sorted list (`O(n log n)` instead of +`O(n^2)`). ++ +However, if you use the list to check if a certain string was added +already, you should not do that (using unsorted_path_list_has_path()), +because the complexity would be quadratic again (but with a worse factor). + +Functions +--------- + +* General ones (works with sorted and unsorted lists as well) + +`print_path_list`:: + + Dump a path_list to stdout, useful mainly for debugging purposes. It + can take an optional header argument and it writes out the + string-pointer pairs of the path_list, each one in its own line. + +`path_list_clear`:: + + Free a path_list. The `path` pointer of the items will be freed in case + the `strdup_paths` member of the path_list is set. The second parameter + controls if the `util` pointer of the items should be freed or not. + +* Functions for sorted lists only + +`path_list_has_path`:: + + Determine if the path_list has a given string or not. + +`path_list_insert`:: + + Insert a new element to the path_list. The returned pointer can be handy + if you want to write something to the `util` pointer of the + path_list_item containing the just added string. ++ +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 +write `path_list_insert(...)->util = ...;`. + +`path_list_lookup`:: + + Look up a given string in the path_list, returning the containing + path_list_item. If the string is not found, NULL is returned. + +* Functions for unsorted lists only + +`path_list_append`:: + + Append a new string to the end of the path_list. + +`sort_path_list`:: + + Make an unsorted list sorted. + +`unsorted_path_list_has_path`:: + + It's like `path_list_has_path()` but for unsorted lists. ++ +This function needs to look through all items, as opposed to its +counterpart for sorted lists, which performs a binary search. + +Data structures +--------------- + +* `struct path_list_item` + +Represents an item of the list. The `path` member is a pointer to the +string, and you may use the `util` member for any purpose, if you want. + +* `struct path_list` + +Represents the list itself. + +. The array of items are available via the `items` member. +. The `nr` member contains the number of items stored in the list. +. The `alloc` member is used to avoid reallocating at every insertion. + You should not tamper with it. +. Setting the `strdup_paths` member to 1 will strdup() the strings + before adding them, see above. diff --git a/Documentation/technical/api-run-command.txt b/Documentation/technical/api-run-command.txt index c364a22c8f..75aa5d4923 100644 --- a/Documentation/technical/api-run-command.txt +++ b/Documentation/technical/api-run-command.txt @@ -30,7 +30,7 @@ Functions start_command() followed by finish_command(). Takes a pointer to a `struct child_process` that specifies the details. -`run_command_v_opt`, `run_command_v_opt_dir`, `run_command_v_opt_cd_env`:: +`run_command_v_opt`, `run_command_v_opt_cd`, `run_command_v_opt_cd_env`:: Convenience functions that encapsulate a sequence of start_command() followed by finish_command(). The argument argv @@ -63,7 +63,7 @@ command to run in a sub-process. The caller: -1. allocates and clears (memset(&chld, '0', sizeof(chld));) a +1. allocates and clears (memset(&chld, 0, sizeof(chld));) a struct child_process variable; 2. initializes the members; 3. calls start_command(); @@ -136,7 +136,7 @@ to produce output that the caller reads. The caller: -1. allocates and clears (memset(&asy, '0', sizeof(asy));) a +1. allocates and clears (memset(&asy, 0, sizeof(asy));) a struct async variable; 2. initializes .proc and .data; 3. calls start_async(); |