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From: Paul Tan <pyokagan@gmail.com>
To: git@vger.kernel.org
Cc: Johannes Schindelin <johannes.schindelin@gmx.de>,
	Stefan Beller <sbeller@google.com>, Paul Tan <pyokagan@gmail.com>
Subject: [PATCH v5 04/44] builtin-am: implement patch queue mechanism
Date: Tue,  7 Jul 2015 22:20:22 +0800	[thread overview]
Message-ID: <1436278862-2638-5-git-send-email-pyokagan@gmail.com> (raw)
In-Reply-To: <1436278862-2638-1-git-send-email-pyokagan@gmail.com>

git-am applies a series of patches. If the process terminates
abnormally, we want to be able to resume applying the series of patches.
This requires the session state to be saved in a persistent location.

Implement the mechanism of a "patch queue", represented by 2 integers --
the index of the current patch we are applying and the index of the last
patch, as well as its lifecycle through the following functions:

* am_setup(), which will set up the state directory
  $GIT_DIR/rebase-apply. As such, even if the process exits abnormally,
  the last-known state will still persist.

* am_load(), which is called if there is an am session in
  progress, to load the last known state from the state directory so we
  can resume applying patches.

* am_run(), which will do the actual patch application. After applying a
  patch, it calls am_next() to increment the current patch index. The
  logic for applying and committing a patch is not implemented yet.

* am_destroy(), which is finally called when we successfully applied all
  the patches in the queue, to clean up by removing the state directory
  and its contents.

Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Stefan Beller <sbeller@google.com>
Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/am.c | 180 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 180 insertions(+)

diff --git a/builtin/am.c b/builtin/am.c
index fd32caf..292f793 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -6,9 +6,174 @@
 #include "cache.h"
 #include "builtin.h"
 #include "exec_cmd.h"
+#include "parse-options.h"
+#include "dir.h"
+
+struct am_state {
+	/* state directory path */
+	char *dir;
+
+	/* current and last patch numbers, 1-indexed */
+	int cur;
+	int last;
+};
+
+/**
+ * Initializes am_state with the default values. The state directory is set to
+ * dir.
+ */
+static void am_state_init(struct am_state *state, const char *dir)
+{
+	memset(state, 0, sizeof(*state));
+
+	assert(dir);
+	state->dir = xstrdup(dir);
+}
+
+/**
+ * Releases memory allocated by an am_state.
+ */
+static void am_state_release(struct am_state *state)
+{
+	if (state->dir)
+		free(state->dir);
+}
+
+/**
+ * Returns path relative to the am_state directory.
+ */
+static inline const char *am_path(const struct am_state *state, const char *path)
+{
+	assert(state->dir);
+	assert(path);
+	return mkpath("%s/%s", state->dir, path);
+}
+
+/**
+ * Returns 1 if there is an am session in progress, 0 otherwise.
+ */
+static int am_in_progress(const struct am_state *state)
+{
+	struct stat st;
+
+	if (lstat(state->dir, &st) < 0 || !S_ISDIR(st.st_mode))
+		return 0;
+	if (lstat(am_path(state, "last"), &st) || !S_ISREG(st.st_mode))
+		return 0;
+	if (lstat(am_path(state, "next"), &st) || !S_ISREG(st.st_mode))
+		return 0;
+	return 1;
+}
+
+/**
+ * Reads the contents of `file` in the `state` directory into `sb`. Returns the
+ * number of bytes read on success, -1 if the file does not exist. If `trim` is
+ * set, trailing whitespace will be removed.
+ */
+static int read_state_file(struct strbuf *sb, const struct am_state *state,
+			const char *file, int trim)
+{
+	strbuf_reset(sb);
+
+	if (strbuf_read_file(sb, am_path(state, file), 0) >= 0) {
+		if (trim)
+			strbuf_trim(sb);
+
+		return sb->len;
+	}
+
+	if (errno == ENOENT)
+		return -1;
+
+	die_errno(_("could not read '%s'"), am_path(state, file));
+}
+
+/**
+ * Loads state from disk.
+ */
+static void am_load(struct am_state *state)
+{
+	struct strbuf sb = STRBUF_INIT;
+
+	if (read_state_file(&sb, state, "next", 1) < 0)
+		die("BUG: state file 'next' does not exist");
+	state->cur = strtol(sb.buf, NULL, 10);
+
+	if (read_state_file(&sb, state, "last", 1) < 0)
+		die("BUG: state file 'last' does not exist");
+	state->last = strtol(sb.buf, NULL, 10);
+
+	strbuf_release(&sb);
+}
+
+/**
+ * Removes the am_state directory, forcefully terminating the current am
+ * session.
+ */
+static void am_destroy(const struct am_state *state)
+{
+	struct strbuf sb = STRBUF_INIT;
+
+	strbuf_addstr(&sb, state->dir);
+	remove_dir_recursively(&sb, 0);
+	strbuf_release(&sb);
+}
+
+/**
+ * Setup a new am session for applying patches
+ */
+static void am_setup(struct am_state *state)
+{
+	if (mkdir(state->dir, 0777) < 0 && errno != EEXIST)
+		die_errno(_("failed to create directory '%s'"), state->dir);
+
+	/*
+	 * NOTE: Since the "next" and "last" files determine if an am_state
+	 * session is in progress, they should be written last.
+	 */
+
+	write_file(am_path(state, "next"), 1, "%d", state->cur);
+
+	write_file(am_path(state, "last"), 1, "%d", state->last);
+}
+
+/**
+ * Increments the patch pointer, and cleans am_state for the application of the
+ * next patch.
+ */
+static void am_next(struct am_state *state)
+{
+	state->cur++;
+	write_file(am_path(state, "next"), 1, "%d", state->cur);
+}
+
+/**
+ * Applies all queued mail.
+ */
+static void am_run(struct am_state *state)
+{
+	while (state->cur <= state->last) {
+
+		/* NEEDSWORK: Patch application not implemented yet */
+
+		am_next(state);
+	}
+
+	am_destroy(state);
+}
 
 int cmd_am(int argc, const char **argv, const char *prefix)
 {
+	struct am_state state;
+
+	const char * const usage[] = {
+		N_("git am [options] [(<mbox>|<Maildir>)...]"),
+		NULL
+	};
+
+	struct option options[] = {
+		OPT_END()
+	};
 
 	/*
 	 * NEEDSWORK: Once all the features of git-am.sh have been
@@ -25,5 +190,20 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		setup_work_tree();
 	}
 
+	git_config(git_default_config, NULL);
+
+	am_state_init(&state, git_path("rebase-apply"));
+
+	argc = parse_options(argc, argv, prefix, options, usage, 0);
+
+	if (am_in_progress(&state))
+		am_load(&state);
+	else
+		am_setup(&state);
+
+	am_run(&state);
+
+	am_state_release(&state);
+
 	return 0;
 }
-- 
2.5.0.rc1.76.gf60a929

  parent reply	other threads:[~2015-07-07 14:21 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-07 14:20 [PATCH v5 00/44] Make git-am a builtin Paul Tan
2015-07-07 14:20 ` [PATCH v5 01/44] wrapper: implement xopen() Paul Tan
2015-07-07 14:20 ` [PATCH v5 02/44] wrapper: implement xfopen() Paul Tan
2015-07-07 14:20 ` [PATCH v5 03/44] builtin-am: implement skeletal builtin am Paul Tan
2015-07-07 14:20 ` Paul Tan [this message]
2015-07-07 14:20 ` [PATCH v5 05/44] builtin-am: split out mbox/maildir patches with git-mailsplit Paul Tan
2015-07-07 14:20 ` [PATCH v5 06/44] builtin-am: auto-detect mbox patches Paul Tan
2015-07-07 14:20 ` [PATCH v5 07/44] builtin-am: extract patch and commit info with git-mailinfo Paul Tan
2015-07-07 14:20 ` [PATCH v5 08/44] builtin-am: apply patch with git-apply Paul Tan
2015-07-07 14:20 ` [PATCH v5 09/44] builtin-am: implement committing applied patch Paul Tan
2015-07-07 14:20 ` [PATCH v5 10/44] builtin-am: refuse to apply patches if index is dirty Paul Tan
2015-07-07 14:20 ` [PATCH v5 11/44] builtin-am: implement --resolved/--continue Paul Tan
2015-07-07 14:20 ` [PATCH v5 12/44] builtin-am: implement --skip Paul Tan
2015-07-13 19:05   ` Stefan Beller
2015-07-14  9:34     ` Paul Tan
2015-07-14 16:54       ` Stefan Beller
2015-07-18 15:22         ` Paul Tan
2015-07-07 14:20 ` [PATCH v5 13/44] builtin-am: implement --abort Paul Tan
2015-07-07 14:20 ` [PATCH v5 14/44] builtin-am: reject patches when there's a session in progress Paul Tan
2015-07-07 14:20 ` [PATCH v5 15/44] builtin-am: implement -q/--quiet Paul Tan
2015-07-07 14:20 ` [PATCH v5 16/44] builtin-am: exit with user friendly message on failure Paul Tan
2015-07-07 14:20 ` [PATCH v5 17/44] builtin-am: implement -s/--signoff Paul Tan
2015-07-07 14:20 ` [PATCH v5 18/44] cache-tree: introduce write_index_as_tree() Paul Tan
2015-07-07 20:10   ` Junio C Hamano
2015-07-07 14:20 ` [PATCH v5 19/44] builtin-am: implement --3way, am.threeWay Paul Tan
2015-07-07 20:14   ` Junio C Hamano
2015-07-14  9:32     ` Paul Tan
2015-07-07 14:20 ` [PATCH v5 20/44] builtin-am: implement --rebasing mode Paul Tan
2015-07-07 14:20 ` [PATCH v5 21/44] builtin-am: bypass git-mailinfo when --rebasing Paul Tan
2015-07-07 14:20 ` [PATCH v5 22/44] builtin-am: handle stray state directory Paul Tan
2015-07-07 14:20 ` [PATCH v5 23/44] builtin-am: implement -u/--utf8 Paul Tan
2015-07-07 14:20 ` [PATCH v5 24/44] builtin-am: implement -k/--keep, --keep-non-patch Paul Tan
2015-07-07 14:20 ` [PATCH v5 25/44] builtin-am: implement --[no-]message-id, am.messageid Paul Tan
2015-07-07 14:20 ` [PATCH v5 26/44] builtin-am: support --keep-cr, am.keepcr Paul Tan
2015-07-07 14:20 ` [PATCH v5 27/44] builtin-am: implement --[no-]scissors Paul Tan
2015-07-07 14:20 ` [PATCH v5 28/44] builtin-am: pass git-apply's options to git-apply Paul Tan
2015-07-07 14:20 ` [PATCH v5 29/44] builtin-am: implement --ignore-date Paul Tan
2015-07-07 14:20 ` [PATCH v5 30/44] builtin-am: implement --committer-date-is-author-date Paul Tan
2015-07-07 14:20 ` [PATCH v5 31/44] builtin-am: implement -S/--gpg-sign, commit.gpgsign Paul Tan
2015-07-07 14:20 ` [PATCH v5 32/44] builtin-am: invoke post-rewrite hook Paul Tan
2015-07-07 14:20 ` [PATCH v5 33/44] builtin-am: support automatic notes copying Paul Tan
2015-07-07 14:20 ` [PATCH v5 34/44] builtin-am: invoke applypatch-msg hook Paul Tan
2015-07-07 14:20 ` [PATCH v5 35/44] builtin-am: invoke pre-applypatch hook Paul Tan
2015-07-07 14:20 ` [PATCH v5 36/44] builtin-am: invoke post-applypatch hook Paul Tan
2015-07-07 14:20 ` [PATCH v5 37/44] builtin-am: rerere support Paul Tan
2015-07-07 14:20 ` [PATCH v5 38/44] builtin-am: support and auto-detect StGit patches Paul Tan
2015-07-07 14:20 ` [PATCH v5 39/44] builtin-am: support and auto-detect StGit series files Paul Tan
2015-07-07 14:20 ` [PATCH v5 40/44] builtin-am: support and auto-detect mercurial patches Paul Tan
2015-07-07 14:20 ` [PATCH v5 41/44] builtin-am: implement -i/--interactive Paul Tan
2015-07-07 14:21 ` [PATCH v5 42/44] builtin-am: implement legacy -b/--binary option Paul Tan
2015-07-07 14:21 ` [PATCH v5 43/44] builtin-am: check for valid committer ident Paul Tan
2015-07-07 14:21 ` [PATCH v5 44/44] builtin-am: remove redirection to git-am.sh Paul Tan
2015-07-07 18:52 ` [PATCH v5 00/44] Make git-am a builtin Junio C Hamano
2015-07-07 19:25   ` Paul Tan
2015-07-08  7:31 ` Junio C Hamano
2015-07-08  7:44   ` Paul Tan
2015-07-08  7:48   ` Junio C Hamano
2015-07-08  8:19     ` Paul Tan
2015-07-09  6:00       ` Junio C Hamano
2015-07-12 12:29         ` Paul Tan
2015-07-12 17:32           ` Junio C Hamano
2015-07-13 22:31 ` Junio C Hamano
2015-07-14 10:08   ` Paul Tan

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