receive-pack hooks updates.

The earlier one conflated update and post-update hooks for no
good reason.  Correct that ugly hack.  Now post-update hooks
will take the list of successfully updated refs.

Signed-off-by: Junio C Hamano <junkio@cox.net>

Documentation/git-receive-pack.txt

@@ -43,35 +43,35 @@ The hook should exit with non-zero status if it wants to
 disallow updating the named ref.  Otherwise it should exit with
 zero.
 
-The same hook is also called with an empty string as refname and
-no other arguments just before git-receive-pack exits.  This can
-be used to implement repository wide cleanup task if needed.
-The exit code from this hook invocation is ignored; the only
-thing left for git-receive-pack to do at that point is to exit
-itself anyway.
-
 Using this hook, it is easy to generate mails on updates to
 the local repository. This example script sends a mail with
 the commits pushed to the repository:
 
 	#!/bin/sh
-	case "$#,$1" in
-	1,) # help packed repository pulled via dumb protocol.
-	    git-update-server-info
-	    ;;
-	*)  # mail out commit update information.
-	    if expr "$2" : '0*$' >/dev/null
-	    then
-		echo "Created now ref."
+	# mail out commit update information.
+	if expr "$2" : '0*$' >/dev/null
+	then
+		echo "Created a new ref, with the following commits:"
 		git-rev-list --pretty "$2"
-	    else
-		echo "New commits"
+	else
+		echo "New commits:"
 		git-rev-list --pretty "$3" "^$2"
-	    fi |
-	    mail -s "Changes to ref $1" commit-list@mydomain
-        esac
+	fi |
+	mail -s "Changes to ref $1" commit-list@mydomain
 	exit 0
 
+Another hook $GIT_DIR/hooks/post-update, if exists and
+executable, is called with the list of refs that have been
+updated.  This can be used to implement repository wide cleanup
+task if needed.  The exit code from this hook invocation is
+ignored; the only thing left for git-receive-pack to do at that
+point is to exit itself anyway.  This hook can be used, for
+example, to run "git-update-server-info" if the repository is
+packed and is served via a dumb transport.
+
+	#!/bin/sh
+	exec git-update-server-info
+
 OPTIONS
 -------
 <directory>::

receive-pack.c

@@ -21,6 +21,7 @@ static void write_head_info(void)
 
 struct command {
 	struct command *next;
+	unsigned char updated;
 	unsigned char old_sha1[20];
 	unsigned char new_sha1[20];
 	char ref_name[0];
@@ -88,7 +89,8 @@ static int run_update_hook(const char *refname,
 	}
 }
 
-static void update(const char *name, unsigned char *old_sha1, unsigned char *new_sha1)
+static int update(const char *name,
+		  unsigned char *old_sha1, unsigned char *new_sha1)
 {
 	char new_hex[60], *old_hex, *lock_name;
 	int newfd, namelen, written;
@@ -101,11 +103,13 @@ static void update(const char *name, unsigned char *old_sha1, unsigned char *new
 	strcpy(new_hex, sha1_to_hex(new_sha1));
 	old_hex = sha1_to_hex(old_sha1);
 	if (!has_sha1_file(new_sha1))
-		die("unpack should have generated %s, but I can't find it!", new_hex);
+		return error("unpack should have generated %s, "
+			     "but I can't find it!", new_hex);
 
 	newfd = open(lock_name, O_CREAT | O_EXCL | O_WRONLY, 0666);
 	if (newfd < 0)
-		die("unable to create %s (%s)", lock_name, strerror(errno));
+		return error("unable to create %s (%s)",
+			     lock_name, strerror(errno));
 
 	/* Write the ref with an ending '\n' */
 	new_hex[40] = '\n';
@@ -117,24 +121,54 @@ static void update(const char *name, unsigned char *old_sha1, unsigned char *new
 	close(newfd);
 	if (written != 41) {
 		unlink(lock_name);
-		die("unable to write %s", lock_name);
+		return error("unable to write %s", lock_name);
 	}
 	if (verify_old_ref(name, old_hex) < 0) {
 		unlink(lock_name);
-		die("%s changed during push", name);
+		return error("%s changed during push", name);
 	}
 	if (run_update_hook(name, old_hex, new_hex)) {
 		unlink(lock_name);
-		fprintf(stderr, "hook declined to update %s\n", name);
+		return error("hook declined to update %s\n", name);
 	}
 	else if (rename(lock_name, name) < 0) {
 		unlink(lock_name);
-		die("unable to replace %s", name);
+		return error("unable to replace %s", name);
 	}
-	else
+	else {
 		fprintf(stderr, "%s: %s -> %s\n", name, old_hex, new_hex);
+		return 0;
+	}
 }
 
+static char update_post_hook[] = "hooks/post-update";
+
+static void run_update_post_hook(struct command *cmd)
+{
+	struct command *cmd_p;
+	int argc;
+	char **argv;
+
+	if (access(update_post_hook, X_OK) < 0)
+		return;
+	for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
+		if (!cmd_p->updated)
+			continue;
+		argc++;
+	}
+	argv = xmalloc(sizeof(*argv) * (1 + argc));
+	argv[0] = update_post_hook;
+
+	for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
+		if (!cmd_p->updated)
+			continue;
+		argv[argc] = xmalloc(strlen(cmd_p->ref_name) + 1);
+		strcpy(argv[argc], cmd_p->ref_name);
+		argc++;
+	}
+	argv[argc] = NULL;
+	run_command_v(argc, argv);
+}
 
 /*
  * This gets called after(if) we've successfully
@@ -145,10 +179,11 @@ static void execute_commands(void)
 	struct command *cmd = commands;
 
 	while (cmd) {
-		update(cmd->ref_name, cmd->old_sha1, cmd->new_sha1);
+		cmd->updated = !update(cmd->ref_name,
+				       cmd->old_sha1, cmd->new_sha1);
 		cmd = cmd->next;
 	}
-	run_update_hook("", NULL, NULL);
+	run_update_post_hook(commands);
 }
 
 static void read_head_info(void)

run-command.c

@@ -2,7 +2,7 @@
 #include "run-command.h"
 #include <sys/wait.h>
 
-static int run_external_command(int argc, const char **argv)
+int run_command_v(int argc, char **argv)
 {
 	pid_t pid = fork();
 
@@ -10,7 +10,7 @@ static int run_external_command(int argc, const char **argv)
 		return -ERR_RUN_COMMAND_FORK;
 	if (!pid) {
 		execvp(argv[0], (char *const*) argv);
-		return -ERR_RUN_COMMAND_EXEC;
+		die("exec %s failed.", argv[0]);
 	}
 	for (;;) {
 		int status, code;
@@ -39,14 +39,12 @@ static int run_external_command(int argc, const char **argv)
 int run_command(const char *cmd, ...)
 {
 	int argc;
-	const char *argv[MAX_RUN_COMMAND_ARGS];
+	char *argv[MAX_RUN_COMMAND_ARGS];
 	const char *arg;
 	va_list param;
 
-	fprintf(stderr, "run-command %s (%d)\n", cmd, ERR_RUN_COMMAND_EXEC);
-
 	va_start(param, cmd);
-	argv[0] = cmd;
+	argv[0] = (char*) cmd;
 	argc = 1;
 	while (argc < MAX_RUN_COMMAND_ARGS) {
 		arg = argv[argc++] = va_arg(param, char *);
@@ -56,5 +54,5 @@ int run_command(const char *cmd, ...)
 	va_end(param);
 	if (MAX_RUN_COMMAND_ARGS <= argc)
 		return error("too many args to run %s", cmd);
-	return run_external_command(argc, argv);
+	return run_command_v(argc, argv);
 }

run-command.h

@@ -11,6 +11,7 @@ enum {
 	ERR_RUN_COMMAND_WAITPID_NOEXIT,
 };
 
+int run_command_v(int argc, char **argv);
 int run_command(const char *cmd, ...);
 
 #endif