Merge branch 'sp/maint-push-sideband' into sp/push-sideband

* sp/maint-push-sideband:
  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
  Update git fsck --full short description to mention packs

Conflicts:
	run-command.c

Author: gitster

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.

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");

builtin-fsck.c

@@ -578,7 +578,7 @@ static struct option fsck_opts[] = {
 	OPT_BOOLEAN(0, "root", &show_root, "report root nodes"),
 	OPT_BOOLEAN(0, "cache", &keep_cache_objects, "make index objects head nodes"),
 	OPT_BOOLEAN(0, "reflogs", &include_reflogs, "make reflogs head nodes (default)"),
-	OPT_BOOLEAN(0, "full", &check_full, "also consider alternate objects"),
+	OPT_BOOLEAN(0, "full", &check_full, "also consider packs and alternate objects"),
 	OPT_BOOLEAN(0, "strict", &check_strict, "enable more strict checking"),
 	OPT_BOOLEAN(0, "lost-found", &write_lost_and_found,
 				"write dangling objects in .git/lost-found"),

builtin-receive-pack.c

@@ -2,6 +2,7 @@
 #include "pack.h"
 #include "refs.h"
 #include "pkt-line.h"
+#include "sideband.h"
 #include "run-command.h"
 #include "exec_cmd.h"
 #include "commit.h"
@@ -27,11 +28,12 @@ static int receive_unpack_limit = -1;
 static int transfer_unpack_limit = -1;
 static int unpack_limit = 100;
 static int report_status;
+static int use_sideband;
 static int prefer_ofs_delta = 1;
 static int auto_update_server_info;
 static int auto_gc = 1;
 static const char *head_name;
-static char *capabilities_to_send;
+static int sent_capabilities;
 
 static enum deny_action parse_deny_action(const char *var, const char *value)
 {
@@ -105,19 +107,21 @@ static int receive_pack_config(const char *var, const char *value, void *cb)
 
 static int show_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 {
-	if (!capabilities_to_send)
+	if (sent_capabilities)
 		packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
 	else
-		packet_write(1, "%s %s%c%s\n",
-			     sha1_to_hex(sha1), path, 0, capabilities_to_send);
-	capabilities_to_send = NULL;
+		packet_write(1, "%s %s%c%s%s\n",
+			     sha1_to_hex(sha1), path, 0,
+			     " report-status delete-refs side-band-64k",
+			     prefer_ofs_delta ? " ofs-delta" : "");
+	sent_capabilities = 1;
 	return 0;
 }
 
 static void write_head_info(void)
 {
 	for_each_ref(show_ref, NULL);
-	if (capabilities_to_send)
+	if (!sent_capabilities)
 		show_ref("capabilities^{}", null_sha1, 0, NULL);
 
 }
@@ -135,11 +139,25 @@ static struct command *commands;
 static const char pre_receive_hook[] = "hooks/pre-receive";
 static const char post_receive_hook[] = "hooks/post-receive";
 
+static int copy_to_sideband(int in, int out, void *arg)
+{
+	char data[128];
+	while (1) {
+		ssize_t sz = xread(in, data, sizeof(data));
+		if (sz <= 0)
+			break;
+		send_sideband(1, 2, data, sz, use_sideband);
+	}
+	close(in);
+	return 0;
+}
+
 static int run_receive_hook(const char *hook_name)
 {
 	static char buf[sizeof(commands->old_sha1) * 2 + PATH_MAX + 4];
 	struct command *cmd;
 	struct child_process proc;
+	struct async muxer;
 	const char *argv[2];
 	int have_input = 0, code;
 
@@ -159,9 +177,23 @@ static int run_receive_hook(const char *hook_name)
 	proc.in = -1;
 	proc.stdout_to_stderr = 1;
 
+	if (use_sideband) {
+		memset(&muxer, 0, sizeof(muxer));
+		muxer.proc = copy_to_sideband;
+		muxer.in = -1;
+		code = start_async(&muxer);
+		if (code)
+			return code;
+		proc.err = muxer.in;
+	}
+
 	code = start_command(&proc);
-	if (code)
+	if (code) {
+		if (use_sideband)
+			finish_async(&muxer);
 		return code;
+	}
+
 	for (cmd = commands; cmd; cmd = cmd->next) {
 		if (!cmd->error_string) {
 			size_t n = snprintf(buf, sizeof(buf), "%s %s %s\n",
@@ -173,13 +205,17 @@ static int run_receive_hook(const char *hook_name)
 		}
 	}
 	close(proc.in);
+	if (use_sideband)
+		finish_async(&muxer);
 	return finish_command(&proc);
 }
 
 static int run_update_hook(struct command *cmd)
 {
 	static const char update_hook[] = "hooks/update";
 	const char *argv[5];
+	struct child_process proc;
+	int code;
 
 	if (access(update_hook, X_OK) < 0)
 		return 0;
@@ -190,8 +226,18 @@ static int run_update_hook(struct command *cmd)
 	argv[3] = sha1_to_hex(cmd->new_sha1);
 	argv[4] = NULL;
 
-	return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN |
-					RUN_COMMAND_STDOUT_TO_STDERR);
+	memset(&proc, 0, sizeof(proc));
+	proc.no_stdin = 1;
+	proc.stdout_to_stderr = 1;
+	proc.err = use_sideband ? -1 : 0;
+	proc.argv = argv;
+
+	code = start_command(&proc);
+	if (code)
+		return code;
+	if (use_sideband)
+		copy_to_sideband(proc.err, -1, NULL);
+	return finish_command(&proc);
 }
 
 static int is_ref_checked_out(const char *ref)
@@ -368,8 +414,9 @@ static char update_post_hook[] = "hooks/post-update";
 static void run_update_post_hook(struct command *cmd)
 {
 	struct command *cmd_p;
-	int argc, status;
+	int argc;
 	const char **argv;
+	struct child_process proc;
 
 	for (argc = 0, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
 		if (cmd_p->error_string)
@@ -391,8 +438,18 @@ static void run_update_post_hook(struct command *cmd)
 		argc++;
 	}
 	argv[argc] = NULL;
-	status = run_command_v_opt(argv, RUN_COMMAND_NO_STDIN
-			| RUN_COMMAND_STDOUT_TO_STDERR);
+
+	memset(&proc, 0, sizeof(proc));
+	proc.no_stdin = 1;
+	proc.stdout_to_stderr = 1;
+	proc.err = use_sideband ? -1 : 0;
+	proc.argv = argv;
+
+	if (!start_command(&proc)) {
+		if (use_sideband)
+			copy_to_sideband(proc.err, -1, NULL);
+		finish_command(&proc);
+	}
 }
 
 static void execute_commands(const char *unpacker_error)
@@ -452,6 +509,8 @@ static void read_head_info(void)
 		if (reflen + 82 < len) {
 			if (strstr(refname + reflen + 1, "report-status"))
 				report_status = 1;
+			if (strstr(refname + reflen + 1, "side-band-64k"))
+				use_sideband = LARGE_PACKET_MAX;
 		}
 		cmd = xmalloc(sizeof(struct command) + len - 80);
 		hashcpy(cmd->old_sha1, old_sha1);
@@ -551,17 +610,25 @@ static const char *unpack(void)
 static void report(const char *unpack_status)
 {
 	struct command *cmd;
-	packet_write(1, "unpack %s\n",
-		     unpack_status ? unpack_status : "ok");
+	struct strbuf buf = STRBUF_INIT;
+
+	packet_buf_write(&buf, "unpack %s\n",
+			 unpack_status ? unpack_status : "ok");
 	for (cmd = commands; cmd; cmd = cmd->next) {
 		if (!cmd->error_string)
-			packet_write(1, "ok %s\n",
-				     cmd->ref_name);
+			packet_buf_write(&buf, "ok %s\n",
+					 cmd->ref_name);
 		else
-			packet_write(1, "ng %s %s\n",
-				     cmd->ref_name, cmd->error_string);
+			packet_buf_write(&buf, "ng %s %s\n",
+					 cmd->ref_name, cmd->error_string);
 	}
-	packet_flush(1);
+	packet_buf_flush(&buf);
+
+	if (use_sideband)
+		send_sideband(1, 1, buf.buf, buf.len, use_sideband);
+	else
+		safe_write(1, buf.buf, buf.len);
+	strbuf_release(&buf);
 }
 
 static int delete_only(struct command *cmd)
@@ -658,10 +725,6 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 	else if (0 <= receive_unpack_limit)
 		unpack_limit = receive_unpack_limit;
 
-	capabilities_to_send = (prefer_ofs_delta) ?
-		" report-status delete-refs ofs-delta " :
-		" report-status delete-refs ";
-
 	if (advertise_refs || !stateless_rpc) {
 		add_alternate_refs();
 		write_head_info();
@@ -695,5 +758,7 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 		if (auto_update_server_info)
 			update_server_info(0);
 	}
+	if (use_sideband)
+		packet_flush(1);
 	return 0;
 }