diff options
| -rw-r--r-- | Documentation/technical/api-sub-process.txt | 59 | ||||
| -rw-r--r-- | Makefile | 1 | ||||
| -rw-r--r-- | convert.c | 104 | ||||
| -rw-r--r-- | sub-process.c | 102 | ||||
| -rw-r--r-- | sub-process.h | 49 |
5 files changed, 212 insertions, 103 deletions
diff --git a/Documentation/technical/api-sub-process.txt b/Documentation/technical/api-sub-process.txt new file mode 100644 index 0000000000..793508cf3e --- /dev/null +++ b/Documentation/technical/api-sub-process.txt @@ -0,0 +1,59 @@ +sub-process API +=============== + +The sub-process API makes it possible to run background sub-processes +for the entire lifetime of a Git invocation. If Git needs to communicate +with an external process multiple times, then this can reduces the process +invocation overhead. Git and the sub-process communicate through stdin and +stdout. + +The sub-processes are kept in a hashmap by command name and looked up +via the subprocess_find_entry function. If an existing instance can not +be found then a new process should be created and started. When the +parent git command terminates, all sub-processes are also terminated. + +This API is based on the run-command API. + +Data structures +--------------- + +* `struct subprocess_entry` + +The sub-process structure. Members should not be accessed directly. + +Types +----- + +'int(*subprocess_start_fn)(struct subprocess_entry *entry)':: + + User-supplied function to initialize the sub-process. This is + typically used to negotiate the interface version and capabilities. + + +Functions +--------- + +`cmd2process_cmp`:: + + Function to test two subprocess hashmap entries for equality. + +`subprocess_start`:: + + Start a subprocess and add it to the subprocess hashmap. + +`subprocess_stop`:: + + Kill a subprocess and remove it from the subprocess hashmap. + +`subprocess_find_entry`:: + + Find a subprocess in the subprocess hashmap. + +`subprocess_get_child_process`:: + + Get the underlying `struct child_process` from a subprocess. + +`subprocess_read_status`:: + + Helper function to read packets looking for the last "status=<foo>" + key/value pair. @@ -838,6 +838,7 @@ LIB_OBJS += streaming.o LIB_OBJS += string-list.o LIB_OBJS += submodule.o LIB_OBJS += submodule-config.o +LIB_OBJS += sub-process.o LIB_OBJS += symlinks.o LIB_OBJS += tag.o LIB_OBJS += tempfile.o @@ -4,6 +4,7 @@ #include "quote.h" #include "sigchain.h" #include "pkt-line.h" +#include "sub-process.h" /* * convert.c - convert a file when checking it out and checking it in. @@ -496,12 +497,6 @@ static int apply_single_file_filter(const char *path, const char *src, size_t le #define CAP_CLEAN (1u<<0) #define CAP_SMUDGE (1u<<1) -struct subprocess_entry { - struct hashmap_entry ent; /* must be the first member! */ - const char *cmd; - struct child_process process; -}; - struct cmd2process { struct subprocess_entry subprocess; /* must be the first member! */ unsigned int supported_capabilities; @@ -510,65 +505,6 @@ struct cmd2process { static int subprocess_map_initialized; static struct hashmap subprocess_map; -static int cmd2process_cmp(const struct subprocess_entry *e1, - const struct subprocess_entry *e2, - const void *unused) -{ - return strcmp(e1->cmd, e2->cmd); -} - -static struct subprocess_entry *subprocess_find_entry(struct hashmap *hashmap, const char *cmd) -{ - struct subprocess_entry key; - - hashmap_entry_init(&key, strhash(cmd)); - key.cmd = cmd; - return hashmap_get(hashmap, &key, NULL); -} - -static void subprocess_read_status(int fd, struct strbuf *status) -{ - struct strbuf **pair; - char *line; - for (;;) { - line = packet_read_line(fd, NULL); - if (!line) - break; - pair = strbuf_split_str(line, '=', 2); - if (pair[0] && pair[0]->len && pair[1]) { - /* the last "status=<foo>" line wins */ - if (!strcmp(pair[0]->buf, "status=")) { - strbuf_reset(status); - strbuf_addbuf(status, pair[1]); - } - } - strbuf_list_free(pair); - } -} - -static void subprocess_stop(struct hashmap *hashmap, struct subprocess_entry *entry) -{ - if (!entry) - return; - - entry->process.clean_on_exit = 0; - kill(entry->process.pid, SIGTERM); - finish_command(&entry->process); - - hashmap_remove(hashmap, entry, NULL); -} - -static void subprocess_exit_handler(struct child_process *process) -{ - sigchain_push(SIGPIPE, SIG_IGN); - /* Closing the pipe signals the subprocess to initiate a shutdown. */ - close(process->in); - close(process->out); - sigchain_pop(SIGPIPE); - /* Finish command will wait until the shutdown is complete. */ - finish_command(process); -} - static int start_multi_file_filter_fn(struct subprocess_entry *subprocess) { int err; @@ -629,44 +565,6 @@ done: return err; } -typedef int(*subprocess_start_fn)(struct subprocess_entry *entry); -int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, const char *cmd, - subprocess_start_fn startfn) -{ - int err; - struct child_process *process; - const char *argv[] = { cmd, NULL }; - - entry->cmd = cmd; - process = &entry->process; - - child_process_init(process); - process->argv = argv; - process->use_shell = 1; - process->in = -1; - process->out = -1; - process->clean_on_exit = 1; - process->clean_on_exit_handler = subprocess_exit_handler; - - err = start_command(process); - if (err) { - error("cannot fork to run subprocess '%s'", cmd); - return err; - } - - hashmap_entry_init(entry, strhash(cmd)); - - err = startfn(entry); - if (err) { - error("initialization for subprocess '%s' failed", cmd); - subprocess_stop(hashmap, entry); - return err; - } - - hashmap_add(hashmap, entry); - return 0; -} - static int apply_multi_file_filter(const char *path, const char *src, size_t len, int fd, struct strbuf *dst, const char *cmd, const unsigned int wanted_capability) diff --git a/sub-process.c b/sub-process.c new file mode 100644 index 0000000000..536b60cced --- /dev/null +++ b/sub-process.c @@ -0,0 +1,102 @@ +/* + * Generic implementation of background process infrastructure. + */ +#include "sub-process.h" +#include "sigchain.h" +#include "pkt-line.h" + +int cmd2process_cmp(const struct subprocess_entry *e1, + const struct subprocess_entry *e2, + const void *unused) +{ + return strcmp(e1->cmd, e2->cmd); +} + +struct subprocess_entry *subprocess_find_entry(struct hashmap *hashmap, const char *cmd) +{ + struct subprocess_entry key; + + hashmap_entry_init(&key, strhash(cmd)); + key.cmd = cmd; + return hashmap_get(hashmap, &key, NULL); +} + +void subprocess_read_status(int fd, struct strbuf *status) +{ + struct strbuf **pair; + char *line; + for (;;) { + line = packet_read_line(fd, NULL); + if (!line) + break; + pair = strbuf_split_str(line, '=', 2); + if (pair[0] && pair[0]->len && pair[1]) { + /* the last "status=<foo>" line wins */ + if (!strcmp(pair[0]->buf, "status=")) { + strbuf_reset(status); + strbuf_addbuf(status, pair[1]); + } + } + strbuf_list_free(pair); + } +} + +void subprocess_stop(struct hashmap *hashmap, struct subprocess_entry *entry) +{ + if (!entry) + return; + + entry->process.clean_on_exit = 0; + kill(entry->process.pid, SIGTERM); + finish_command(&entry->process); + + hashmap_remove(hashmap, entry, NULL); +} + +static void subprocess_exit_handler(struct child_process *process) +{ + sigchain_push(SIGPIPE, SIG_IGN); + /* Closing the pipe signals the subprocess to initiate a shutdown. */ + close(process->in); + close(process->out); + sigchain_pop(SIGPIPE); + /* Finish command will wait until the shutdown is complete. */ + finish_command(process); +} + +int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, const char *cmd, + subprocess_start_fn startfn) +{ + int err; + struct child_process *process; + const char *argv[] = { cmd, NULL }; + + entry->cmd = cmd; + process = &entry->process; + + child_process_init(process); + process->argv = argv; + process->use_shell = 1; + process->in = -1; + process->out = -1; + process->clean_on_exit = 1; + process->clean_on_exit_handler = subprocess_exit_handler; + + err = start_command(process); + if (err) { + error("cannot fork to run subprocess '%s'", cmd); + return err; + } + + hashmap_entry_init(entry, strhash(cmd)); + + err = startfn(entry); + if (err) { + error("initialization for subprocess '%s' failed", cmd); + subprocess_stop(hashmap, entry); + return err; + } + + hashmap_add(hashmap, entry); + return 0; +} diff --git a/sub-process.h b/sub-process.h new file mode 100644 index 0000000000..a88e782bfc --- /dev/null +++ b/sub-process.h @@ -0,0 +1,49 @@ +#ifndef SUBPROCESS_H +#define SUBPROCESS_H + +#include "git-compat-util.h" +#include "hashmap.h" +#include "run-command.h" + +/* + * Generic implementation of background process infrastructure. + * See Documentation/technical/api-background-process.txt. + */ + + /* data structures */ + +struct subprocess_entry { + struct hashmap_entry ent; /* must be the first member! */ + const char *cmd; + struct child_process process; +}; + +/* subprocess functions */ + +int cmd2process_cmp(const struct subprocess_entry *e1, + const struct subprocess_entry *e2, const void *unused); + +typedef int(*subprocess_start_fn)(struct subprocess_entry *entry); +int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, const char *cmd, + subprocess_start_fn startfn); + +void subprocess_stop(struct hashmap *hashmap, struct subprocess_entry *entry); + +struct subprocess_entry *subprocess_find_entry(struct hashmap *hashmap, const char *cmd); + +/* subprocess helper functions */ + +static inline struct child_process *subprocess_get_child_process( + struct subprocess_entry *entry) +{ + return &entry->process; +} + +/* + * Helper function that will read packets looking for "status=<foo>" + * key/value pairs and return the value from the last "status" packet + */ + +void subprocess_read_status(int fd, struct strbuf *status); + +#endif |