Merge branch 'jc/receive-verify'

* jc/receive-verify:
  receive-pack: check connectivity before concluding "git push"
  check_everything_connected(): libify
  check_everything_connected(): refactor to use an iterator
  fetch: verify we have everything we need before updating our ref

Conflicts:
	builtin/fetch.c

5 files changed, 141 insertions, 56 deletions

diff --git a/Makefile b/Makefile
index 68201dea7..741aac424 100644
--- a/Makefile
+++ b/Makefile
@@ -516,6 +516,7 @@ LIB_H += compat/win32/pthread.h
 LIB_H += compat/win32/syslog.h
 LIB_H += compat/win32/sys/poll.h
 LIB_H += compat/win32/dirent.h
+LIB_H += connected.h
 LIB_H += csum-file.h
 LIB_H += decorate.h
 LIB_H += delta.h
@@ -596,6 +597,7 @@ LIB_OBJS += commit.o
 LIB_OBJS += compat/obstack.o
 LIB_OBJS += config.o
 LIB_OBJS += connect.o
+LIB_OBJS += connected.o
 LIB_OBJS += convert.o
 LIB_OBJS += copy.o
 LIB_OBJS += csum-file.o
diff --git a/builtin/fetch.c b/builtin/fetch.c
index ead8c9d5c..7a4e41cca 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -13,6 +13,7 @@
 #include "sigchain.h"
 #include "transport.h"
 #include "submodule.h"
+#include "connected.h"
 
 static const char * const builtin_fetch_usage[] = {
 	"git fetch [<options>] [<repository> [<refspec>...]]",
@@ -345,62 +346,16 @@ static int update_local_ref(struct ref *ref,
 	}
 }
 
-/*
- * The ref_map records the tips of the refs we are fetching. If
- *
- *  $ git rev-list --verify-objects --stdin --not --all
- *
- * (feeding all the refs in ref_map on its standard input) does not
- * error out, that means everything reachable from these updated refs
- * locally exists and is connected to some of our existing refs.
- *
- * Returns 0 if everything is connected, non-zero otherwise.
- */
-static int check_everything_connected(struct ref *ref_map, int quiet)
+static int iterate_ref_map(void *cb_data, unsigned char sha1[20])
 {
-	struct child_process rev_list;
-	const char *argv[] = {"rev-list", "--verify-objects",
-			      "--stdin", "--not", "--all", NULL, NULL};
-	char commit[41];
-	struct ref *ref;
-	int err = 0;
-
-	if (!ref_map)
-		return 0;
-
-	if (quiet)
-		argv[5] = "--quiet";
-
-	memset(&rev_list, 0, sizeof(rev_list));
-	rev_list.argv = argv;
-	rev_list.git_cmd = 1;
-	rev_list.in = -1;
-	rev_list.no_stdout = 1;
-	rev_list.no_stderr = quiet;
-	if (start_command(&rev_list))
-		return error(_("Could not run 'git rev-list'"));
-
-	sigchain_push(SIGPIPE, SIG_IGN);
-
-	memcpy(commit + 40, "\n", 2);
-	for (ref = ref_map; ref; ref = ref->next) {
-		memcpy(commit, sha1_to_hex(ref->old_sha1), 40);
-		if (write_in_full(rev_list.in, commit, 41) < 0) {
-			if (errno != EPIPE && errno != EINVAL)
-				error(_("failed write to rev-list: %s"),
-				      strerror(errno));
-			err = -1;
-			break;
-		}
-	}
-	if (close(rev_list.in)) {
-		error(_("failed to close rev-list's stdin: %s"), strerror(errno));
-		err = -1;
-	}
-
-	sigchain_pop(SIGPIPE);
+	struct ref **rm = cb_data;
+	struct ref *ref = *rm;
 
-	return finish_command(&rev_list) || err;
+	if (!ref)
+		return -1; /* end of the list */
+	*rm = ref->next;
+	hashcpy(sha1, ref->old_sha1);
+	return 0;
 }
 
 static int store_updated_refs(const char *raw_url, const char *remote_name,
@@ -423,7 +378,8 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
 	else
 		url = xstrdup("foreign");
 
-	if (check_everything_connected(ref_map, 0))
+	rm = ref_map;
+	if (check_everything_connected(iterate_ref_map, 0, &rm))
 		return error(_("%s did not send all necessary objects\n"), url);
 
 	for (rm = ref_map; rm; rm = rm->next) {
@@ -522,6 +478,8 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
  */
 static int quickfetch(struct ref *ref_map)
 {
+	struct ref *rm = ref_map;
+
 	/*
 	 * If we are deepening a shallow clone we already have these
 	 * objects reachable.  Running rev-list here will return with
@@ -531,7 +489,7 @@ static int quickfetch(struct ref *ref_map)
 	 */
 	if (depth)
 		return -1;
-	return check_everything_connected(ref_map, 1);
+	return check_everything_connected(iterate_ref_map, 1, &rm);
 }
 
 static int fetch_refs(struct transport *transport, struct ref *ref_map)
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 4cc03065b..9b56be3cc 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -11,6 +11,7 @@
 #include "transport.h"
 #include "string-list.h"
 #include "sha1-array.h"
+#include "connected.h"
 
 static const char receive_pack_usage[] = "git receive-pack <git-dir>";
 
@@ -585,6 +586,43 @@ static void check_aliased_updates(struct command *commands)
 	string_list_clear(&ref_list, 0);
 }
 
+static int command_singleton_iterator(void *cb_data, unsigned char sha1[20])
+{
+	struct command **cmd_list = cb_data;
+	struct command *cmd = *cmd_list;
+
+	if (!cmd)
+		return -1; /* end of list */
+	*cmd_list = NULL; /* this returns only one */
+	hashcpy(sha1, cmd->new_sha1);
+	return 0;
+}
+
+static void set_connectivity_errors(struct command *commands)
+{
+	struct command *cmd;
+
+	for (cmd = commands; cmd; cmd = cmd->next) {
+		struct command *singleton = cmd;
+		if (!check_everything_connected(command_singleton_iterator,
+						0, &singleton))
+			continue;
+		cmd->error_string = "missing necessary objects";
+	}
+}
+
+static int iterate_receive_command_list(void *cb_data, unsigned char sha1[20])
+{
+	struct command **cmd_list = cb_data;
+	struct command *cmd = *cmd_list;
+
+	if (!cmd)
+		return -1; /* end of list */
+	*cmd_list = cmd->next;
+	hashcpy(sha1, cmd->new_sha1);
+	return 0;
+}
+
 static void execute_commands(struct command *commands, const char *unpacker_error)
 {
 	struct command *cmd;
@@ -596,6 +634,11 @@ static void execute_commands(struct command *commands, const char *unpacker_erro
 		return;
 	}
 
+	cmd = commands;
+	if (check_everything_connected(iterate_receive_command_list,
+				       0, &cmd))
+		set_connectivity_errors(commands);
+
 	if (run_receive_hook(commands, pre_receive_hook)) {
 		for (cmd = commands; cmd; cmd = cmd->next)
 			cmd->error_string = "pre-receive hook declined";
diff --git a/connected.c b/connected.c
new file mode 100644
index 000000000..d7624230d
--- /dev/null
+++ b/connected.c
@@ -0,0 +1,62 @@
+#include "cache.h"
+#include "run-command.h"
+#include "sigchain.h"
+#include "connected.h"
+
+/*
+ * If we feed all the commits we want to verify to this command
+ *
+ *  $ git rev-list --verify-objects --stdin --not --all
+ *
+ * and if it does not error out, that means everything reachable from
+ * these commits locally exists and is connected to some of our
+ * existing refs.
+ *
+ * Returns 0 if everything is connected, non-zero otherwise.
+ */
+int check_everything_connected(sha1_iterate_fn fn, int quiet, void *cb_data)
+{
+	struct child_process rev_list;
+	const char *argv[] = {"rev-list", "--verify-objects",
+			      "--stdin", "--not", "--all", NULL, NULL};
+	char commit[41];
+	unsigned char sha1[20];
+	int err = 0;
+
+	if (fn(cb_data, sha1))
+		return err;
+
+	if (quiet)
+		argv[5] = "--quiet";
+
+	memset(&rev_list, 0, sizeof(rev_list));
+	rev_list.argv = argv;
+	rev_list.git_cmd = 1;
+	rev_list.in = -1;
+	rev_list.no_stdout = 1;
+	rev_list.no_stderr = quiet;
+	if (start_command(&rev_list))
+		return error(_("Could not run 'git rev-list'"));
+
+	sigchain_push(SIGPIPE, SIG_IGN);
+
+	commit[40] = '\n';
+	do {
+		memcpy(commit, sha1_to_hex(sha1), 40);
+		if (write_in_full(rev_list.in, commit, 41) < 0) {
+			if (errno != EPIPE && errno != EINVAL)
+				error(_("failed write to rev-list: %s"),
+				      strerror(errno));
+			err = -1;
+			break;
+		}
+	} while (!fn(cb_data, sha1));
+
+	if (close(rev_list.in)) {
+		error(_("failed to close rev-list's stdin: %s"), strerror(errno));
+		err = -1;
+	}
+
+	sigchain_pop(SIGPIPE);
+	return finish_command(&rev_list) || err;
+}
diff --git a/connected.h b/connected.h
new file mode 100644
index 000000000..7e4585a6c
--- /dev/null
+++ b/connected.h
@@ -0,0 +1,20 @@
+#ifndef CONNECTED_H
+#define CONNECTED_H
+
+/*
+ * Take callback data, and return next object name in the buffer.
+ * When called after returning the name for the last object, return -1
+ * to signal EOF, otherwise return 0.
+ */
+typedef int (*sha1_iterate_fn)(void *, unsigned char [20]);
+
+/*
+ * Make sure that our object store has all the commits necessary to
+ * connect the ancestry chain to some of our existing refs, and all
+ * the trees and blobs that these commits use.
+ *
+ * Return 0 if Ok, non zero otherwise (i.e. some missing objects)
+ */
+extern int check_everything_connected(sha1_iterate_fn, int quiet, void *cb_data);
+
+#endif /* CONNECTED_H */