From: Emily Shaffer <redacted> 

This adds a callback mechanism for feeding stdin to hooks 
alongside the existing path_to_stdin (which slurps a file's 
content to stdin). 

The advantage of this new callback is that it can feed stdin 
without going through the FS layer. This helps when feeding 
large amount of data and uses the run-command parallel stdin 
callback introduced in the preceding commit. 

Signed-off-by: Emily Shaffer <redacted> 
Signed-off-by: Ævar Arnfjörð Bjarmason <redacted> 
Signed-off-by: Adrian Ratiu <redacted> --- 
 hook.c | 15 +++++++++++++++ hook.h | 38 
 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 53 
 insertions(+) 

diff --git a/hook.c b/hook.c index b3de1048bf..cd2bb7418a 100644 
--- a/hook.c +++ b/hook.c @@ -65,11 +65,22 @@ static int 

pick_next_hook(struct child_process *cp, 
  cp->no_stdin = 1; strvec_pushv(&cp->env, 
 hook_cb->options->env.v); 
+ +	if (hook_cb->options->path_to_stdin && 
hook_cb->options->feed_pipe) +		BUG("options 
path_to_stdin and feed_pipe are mutually exclusive"); + 
 	/* reopen the file for stdin; run_command closes it. */ if 
 (hook_cb->options->path_to_stdin) { cp->no_stdin = 0; cp->in = 
 xopen(hook_cb->options->path_to_stdin, O_RDONLY); } 
+ +	if (hook_cb->options->feed_pipe) { + 
cp->no_stdin = 0; +		/* start_command() will allocate a 
pipe / stdin fd for us */ +		cp->in = -1; +	} + 
 	cp->stdout_to_stderr = 1; cp->trace2_hook_name = 
 hook_cb->hook_name; cp->dir = hook_cb->options->dir; 

@@ -140,6 +151,7 @@ int run_hooks_opt(struct repository *r, 

const char *hook_name, 
  .get_next_task = pick_next_hook, .start_failure = 
 notify_start_failure, 
+		.feed_pipe = options->feed_pipe, 
 		.task_finished = notify_hook_finished,  .data = 
 &cb_data, 

@@ -148,6 +160,9 @@ int run_hooks_opt(struct repository *r, 

const char *hook_name, 
 	if (!options) BUG("a struct run_hooks_opt must be provided 
 to run_hooks");  
+	if (options->path_to_stdin && options->feed_pipe) + 
BUG("options path_to_stdin and feed_pipe are mutually 
exclusive"); + 
 	if (options->invoked_hook) *options->invoked_hook = 0;  

diff --git a/hook.h b/hook.h index 11863fa734..dd87326a5a 100644 
--- a/hook.h +++ b/hook.h @@ -1,6 +1,7 @@ 
 #ifndef HOOK_H #define HOOK_H #include "strvec.h" 
+#include "run-command.h" 
  struct repository;  

@@ -37,6 +38,43 @@ struct run_hooks_opt 
 	 * Path to file which should be piped to stdin for each 
 hook.  */ const char *path_to_stdin; 
+ +	/** +	 * Callback used to incrementally feed a child 

hook stdin pipe.  +	 * +	 * Useful especially if a hook 
consumes large quantities of data +	 * (e.g. a list of all 
refs in a client push), so feeding it via +	 * in-memory 
strings or slurping to/from files is inefficient.  +	 * While 
the callback allows piecemeal writing, it can also be +	 * 
used for smaller inputs, where it gets called only once.  +	 * 
+	 * Add hook callback initalization context to 
`feed_pipe_ctx`.  +	 * Add Hook callback internal state to 
`feed_pipe_cb_data`.  +	 * +	 */ +	feed_pipe_fn 
feed_pipe; + +	/** +	 * Opaque data pointer used to 
pass context to `feed_pipe_fn`.  +	 * +	 * It can be 
accessed via the second callback arg: +	 * ((struct 
hook_cb_data *) pp_cb)->hook_cb->options->feed_pipe_ctx; +	 * 
+	 * The caller is responsible for managing the memory for 
this data.  +	 * Only useful when using 
`run_hooks_opt.feed_pipe`, otherwise ignore it.  +	 */ + 
void *feed_pipe_ctx; + +	/** +	 * Opaque data pointer 
used to keep internal state across callback calls.  +	 * +	 * 
It can be accessed via the second callback arg: +	 * 
((struct hook_cb_data *) 
pp_cb)->hook_cb->options->feed_pipe_cb_data;