[PATCH v2 2/6] run-command: support custom fd-set in async
- From
Shawn O. Pearce <spearce@spearce.org>
- Date
- Feb 5, 2010, 20:57 UTC
- Message-ID
- <1265403462-20572-3-git-send-email-spearce@spearce.org>
- In-Reply-To
- <1265403462-20572-1-git-send-email-spearce@spearce.org>
From: Erik Faye-Lund <kusmabite@gmail.com>
This patch adds the possibility to supply a set of non-0 file descriptors for async process communication instead of the default-created pipe.
Additionally, we now support bi-directional communiction with the async procedure, by giving the async function both read and write file descriptors.
To retain compatiblity and similar "API feel" with start_command, we require start_async callers to set .out = -1 to get a readable file descriptor. If either of .in or .out is 0, we supply no file descriptor to the async process.
[sp: Note: Erik started this patch, and a huge bulk of it is
his work. All bugs were introduced later by Shawn.]Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com> Signed-off-by: Shawn O. Pearce <spearce@spearce.org> --- Documentation/technical/api-run-command.txt | 50 +++++++++++++--- builtin-fetch-pack.c | 7 +- convert.c | 5 +- remote-curl.c | 7 +- run-command.c | 83 ++++++++++++++++++++++---- run-command.h | 9 ++- upload-pack.c | 7 +- 7 files changed, 131 insertions(+), 37 deletions(-)
diff --git a/Documentation/technical/api-run-command.txt b/Documentation/technical/api-run-command.txt index a1280dd..8994859 100644 --- a/Documentation/technical/api-run-command.txt +++ b/Documentation/technical/api-run-command.txt @@ -64,8 +64,8 @@ The functions above do the following: `start_async`:: Run a function asynchronously. Takes a pointer to a `struct - async` that specifies the details and returns a pipe FD - from which the caller reads. See below for details. + async` that specifies the details and returns a set of pipe FDs + for communication with the function. See below for details. `finish_async`:: @@ -180,17 +180,47 @@ The caller: struct async variable; 2. initializes .proc and .data; 3. calls start_async(); -4. processes the data by reading from the fd in .out; -5. closes .out; +4. processes communicates with proc through .in and .out; +5. closes .in and .out; 6. calls finish_async(). +The members .in, .out are used to provide a set of fd's for +communication between the caller and the callee as follows: + +. Specify 0 to have no file descriptor passed. The callee will + receive -1 in the corresponding argument. + +. Specify < 0 to have a pipe allocated; start_async() replaces + with the pipe FD in the following way: + + .in: Returns the writable pipe end into which the caller + writes; the readable end of the pipe becomes the function's + in argument. + + .out: Returns the readable pipe end from which the caller + reads; the writable end of the pipe becomes the function's + out argument. + + The caller of start_async() must close the returned FDs after it + has completed reading from/writing from them. + +. Specify a file descriptor > 0 to be used by the function: + + .in: The FD must be readable; it becomes the function's in. + .out: The FD must be writable; it becomes the function's out. + + The specified FD is closed by start_async(), even if it fails to + run the function. + The function pointer in .proc has the following signature: - int proc(int fd, void *data); + int proc(int in, int out, void *data); -. fd specifies a writable file descriptor to which the function must - write the data that it produces. The function *must* close this - descriptor before it returns. +. in, out specifies a set of file descriptors to which the function + must read/write the data that it needs/produces. The function + *must* close these descriptors before it returns. A descriptor + may be -1 if the caller did not configure a descriptor for that + direction. . data is the value that the caller has specified in the .data member of struct async. @@ -205,8 +235,8 @@ because this facility is implemented by a pipe to a forked process on UNIX, but by a thread in the same address space on Windows: . It cannot change the program's state (global variables, environment, - etc.) in a way that the caller notices; in other words, .out is the - only communication channel to the caller. + etc.) in a way that the caller notices; in other words, .in and .out + are the only communication channels to the caller. . It must not change the program's state that the caller of the facility also uses. diff --git a/builtin-fetch-pack.c b/builtin-fetch-pack.c index 8ed4a6f..dbd8b7b 100644 --- a/builtin-fetch-pack.c +++ b/builtin-fetch-pack.c @@ -586,12 +586,12 @@ static int everything_local(struct ref **refs, int nr_match, char **match) return retval; } -static int sideband_demux(int fd, void *data) +static int sideband_demux(int in, int out, void *data) { int *xd = data; - int ret = recv_sideband("fetch-pack", xd[0], fd); - close(fd); + int ret = recv_sideband("fetch-pack", xd[0], out); + close(out); return ret; } @@ -613,6 +613,7 @@ static int get_pack(int xd[2], char **pack_lockfile) */ demux.proc = sideband_demux; demux.data = xd; + demux.out = -1; if (start_async(&demux)) die("fetch-pack: unable to fork off sideband" " demultiplexer"); diff --git a/convert.c b/convert.c index 491e714..e70ee09 100644 --- a/convert.c +++ b/convert.c @@ -241,7 +241,7 @@ struct filter_params { const char *cmd; }; -static int filter_buffer(int fd, void *data) +static int filter_buffer(int in, int out, void *data) { /* * Spawn cmd and feed the buffer contents through its stdin. @@ -254,7 +254,7 @@ static int filter_buffer(int fd, void *data) memset(&child_process, 0, sizeof(child_process)); child_process.argv = argv; child_process.in = -1; - child_process.out = fd; + child_process.out = out; if (start_command(&child_process)) return error("cannot fork to run external filter %s", params->cmd); @@ -291,6 +291,7 @@ static int apply_filter(const char *path, const char *src, size_t len, memset(&async, 0, sizeof(async)); async.proc = filter_buffer; async.data = ¶ms; + async.out = -1; params.src = src; params.size = len; params.cmd = cmd; diff --git a/remote-curl.c b/remote-curl.c index 3edbf57..6bb3366 100644 --- a/remote-curl.c +++ b/remote-curl.c @@ -184,13 +184,13 @@ static struct discovery* discover_refs(const char *service) return last; } -static int write_discovery(int fd, void *data) +static int write_discovery(int in, int out, void *data) { struct discovery *heads = data; int err = 0; - if (write_in_full(fd, heads->buf, heads->len) != heads->len) + if (write_in_full(out, heads->buf, heads->len) != heads->len) err = 1; - close(fd); + close(out); return err; } @@ -202,6 +202,7 @@ static struct ref *parse_git_refs(struct discovery *heads) memset(&async, 0, sizeof(async)); async.proc = write_discovery; async.data = heads; + async.out = -1; if (start_async(&async)) die("cannot start thread to parse advertised refs"); diff --git a/run-command.c b/run-command.c index bfd2312..0d95340 100644 --- a/run-command.c +++ b/run-command.c @@ -327,17 +327,51 @@ int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const static unsigned __stdcall run_thread(void *data) { struct async *async = data; - return async->proc(async->fd_for_proc, async->data); + return async->proc(async->proc_in, async->proc_out, async->data); } #endif int start_async(struct async *async) { - int pipe_out[2]; + int need_in, need_out; + int fdin[2], fdout[2]; + int proc_in, proc_out; - if (pipe(pipe_out) < 0) - return error("cannot create pipe: %s", strerror(errno)); - async->out = pipe_out[0]; + need_in = async->in < 0; + if (need_in) { + if (pipe(fdin) < 0) { + if (async->out > 0) + close(async->out); + return error("cannot create pipe: %s", strerror(errno)); + } + async->in = fdin[1]; + } + + need_out = async->out < 0; + if (need_out) { + if (pipe(fdout) < 0) { + if (need_in) + close_pair(fdin); + else if (async->in) + close(async->in); + return error("cannot create pipe: %s", strerror(errno)); + } + async->out = fdout[0]; + } + + if (need_in) + proc_in = fdin[0]; + else if (async->in) + proc_in = async->in; + else + proc_in = -1; + + if (need_out) + proc_out = fdout[1]; + else if (async->out) + proc_out = async->out; + else + proc_out = -1; #ifndef WIN32 /* Flush stdio before fork() to avoid cloning buffers */ @@ -346,24 +380,47 @@ int start_async(struct async *async) async->pid = fork(); if (async->pid < 0) { error("fork (async) failed: %s", strerror(errno)); - close_pair(pipe_out); - return -1; + goto error; } if (!async->pid) { - close(pipe_out[0]); - exit(!!async->proc(pipe_out[1], async->data)); + if (need_in) + close(fdin[1]); + if (need_out) + close(fdout[0]); + exit(!!async->proc(proc_in, proc_out, async->data)); } - close(pipe_out[1]); + + if (need_in) + close(fdin[0]); + else if (async->in) + close(async->in); + + if (need_out) + close(fdout[1]); + else if (async->out) + close(async->out); #else - async->fd_for_proc = pipe_out[1]; + async->proc_in = proc_in; + async->proc_out = proc_out; async->tid = (HANDLE) _beginthreadex(NULL, 0, run_thread, async, 0, NULL); if (!async->tid) { error("cannot create thread: %s", strerror(errno)); - close_pair(pipe_out); - return -1; + goto error; } #endif return 0; + +error: + if (need_in) + close_pair(fdin); + else if (async->in) + close(async->in); + + if (need_out) + close_pair(fdout); + else if (async->out) + close(async->out); + return -1; } int finish_async(struct async *async) diff --git a/run-command.h b/run-command.h index a29171a..65ccb1c 100644 --- a/run-command.h +++ b/run-command.h @@ -64,17 +64,20 @@ int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const */ struct async { /* - * proc writes to fd and closes it; + * proc reads from in; closes it before return + * proc writes to out; closes it before return * returns 0 on success, non-zero on failure */ - int (*proc)(int fd, void *data); + int (*proc)(int in, int out, void *data); void *data; + int in; /* caller writes here and closes it */ int out; /* caller reads from here and closes it */ #ifndef WIN32 pid_t pid; #else HANDLE tid; - int fd_for_proc; + int proc_in; + int proc_out; #endif }; diff --git a/upload-pack.c b/upload-pack.c index df15181..dc464d7 100644 --- a/upload-pack.c +++ b/upload-pack.c @@ -105,12 +105,12 @@ static void show_edge(struct commit *commit) fprintf(pack_pipe, "-%s\n", sha1_to_hex(commit->object.sha1)); } -static int do_rev_list(int fd, void *create_full_pack) +static int do_rev_list(int in, int out, void *create_full_pack) { int i; struct rev_info revs; - pack_pipe = xfdopen(fd, "w"); + pack_pipe = xfdopen(out, "w"); init_revisions(&revs, NULL); revs.tag_objects = 1; revs.tree_objects = 1; @@ -162,8 +162,9 @@ static void create_pack_file(void) int arg = 0; if (shallow_nr) { + memset(&rev_list, 0, sizeof(rev_list)); rev_list.proc = do_rev_list; - rev_list.data = 0; + rev_list.out = -1; if (start_async(&rev_list)) die("git upload-pack: unable to fork git-rev-list"); argv[arg++] = "pack-objects";
-- 1.7.0.rc1.199.g9253ab