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authorJunio C Hamano <gitster@pobox.com>2010-02-21 20:00:07 (GMT)
committerJunio C Hamano <gitster@pobox.com>2010-02-21 20:00:07 (GMT)
commit5f8a0de98b727b9bfaea0f3318066109fd6745b8 (patch)
tree0f0647050dea5edcb7bb36ccd298ca6e842def7c /Documentation/technical/api-run-command.txt
parent25666af37bf2998ff5e78c8ac6b92a0708af2f3d (diff)
parentcc8eb6407e88a46da6d41e18cffed3878f2c53cf (diff)
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Merge branch 'sp/push-sideband'
* sp/push-sideband: receive-pack: Send internal errors over side-band #2 t5401: Use a bare repository for the remote peer receive-pack: Send hook output over side band #2 receive-pack: Wrap status reports inside side-band-64k receive-pack: Refactor how capabilities are shown to the client send-pack: demultiplex a sideband stream with status data run-command: support custom fd-set in async run-command: Allow stderr to be a caller supplied pipe
Diffstat (limited to 'Documentation/technical/api-run-command.txt')
-rw-r--r--Documentation/technical/api-run-command.txt52
1 files changed, 41 insertions, 11 deletions
diff --git a/Documentation/technical/api-run-command.txt b/Documentation/technical/api-run-command.txt
index 68bf4ca..44876fa 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`::
@@ -135,7 +135,7 @@ stderr as follows:
.in: The FD must be readable; it becomes child's stdin.
.out: The FD must be writable; it becomes child's stdout.
- .err > 0 is not supported.
+ .err: The FD must be writable; it becomes child's stderr.
The specified FD is closed by start_command(), even if it fails to
run the sub-process!
@@ -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.