factor out refresh_and_write_cache function

Getting the lock for the index, refreshing it and then writing it is a
pattern that happens more than once throughout the codebase, and isn't
trivial to get right.  Factor out the refresh_and_write_cache function
from builtin/am.c to read-cache.c, so it can be re-used in other
places in a subsequent commit.

Note that we return different error codes for failing to refresh the
cache, and failing to write the index.  The current caller only cares
about failing to write the index.  However for other callers we're
going to convert in subsequent patches we will need this distinction.

Helped-by: Martin Ågren <martin.agren@gmail.com>
Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/am.c b/builtin/am.c
index 1aea657a7f0b56345e1b2d5f8f32df439e278e80..92e0e700695d5580cc7ee6987264d9a50ed3f7fe 100644 (file)
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -1071,19 +1071,6 @@ static const char *msgnum(const struct am_state *state)
        return sb.buf;
 }
 
-/**
- * Refresh and write index.
- */
-static void refresh_and_write_cache(void)
-{
-       struct lock_file lock_file = LOCK_INIT;
-
-       hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
-       refresh_cache(REFRESH_QUIET);
-       if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
-               die(_("unable to write index file"));
-}
-
 /**
  * Dies with a user-friendly message on how to proceed after resolving the
  * problem. This message can be overridden with state->resolvemsg.
@@ -1703,7 +1690,8 @@ static void am_run(struct am_state *state, int resume)
 
        unlink(am_path(state, "dirtyindex"));
 
-       refresh_and_write_cache();
+       if (refresh_and_write_cache(REFRESH_QUIET, 0, 0) < 0)
+               die(_("unable to write index file"));
 
        if (repo_index_has_changes(the_repository, NULL, &sb)) {
                write_state_bool(state, "dirtyindex", 1);

diff --git a/cache.h b/cache.h
index b1da1ab08faad3da19657a9a5dcf5f2592c2127c..68a54f50ac1e4f725043e799297b28706ce9b4b4 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -414,6 +414,7 @@ extern struct index_state the_index;
 #define add_file_to_cache(path, flags) add_file_to_index(&the_index, (path), (flags))
 #define chmod_cache_entry(ce, flip) chmod_index_entry(&the_index, (ce), (flip))
 #define refresh_cache(flags) refresh_index(&the_index, (flags), NULL, NULL, NULL)
+#define refresh_and_write_cache(refresh_flags, write_flags, gentle) repo_refresh_and_write_index(the_repository, (refresh_flags), (write_flags), (gentle), NULL, NULL, NULL)
 #define ce_match_stat(ce, st, options) ie_match_stat(&the_index, (ce), (st), (options))
 #define ce_modified(ce, st, options) ie_modified(&the_index, (ce), (st), (options))
 #define cache_dir_exists(name, namelen) index_dir_exists(&the_index, (name), (namelen))
@@ -812,6 +813,23 @@ void fill_stat_cache_info(struct index_state *istate, struct cache_entry *ce, st
 #define REFRESH_IN_PORCELAIN   0x0020  /* user friendly output, not "needs update" */
 #define REFRESH_PROGRESS       0x0040  /* show progress bar if stderr is tty */
 int refresh_index(struct index_state *, unsigned int flags, const struct pathspec *pathspec, char *seen, const char *header_msg);
+/*
+ * Refresh the index and write it to disk.
+ *
+ * 'refresh_flags' is passed directly to 'refresh_index()', while
+ * 'COMMIT_LOCK | write_flags' is passed to 'write_locked_index()', so
+ * the lockfile is always either committed or rolled back.
+ *
+ * If 'gentle' is passed, errors locking the index are ignored.
+ *
+ * Return 1 if refreshing the index returns an error, -1 if writing
+ * the index to disk fails, 0 on success.
+ *
+ * Note that if refreshing the index returns an error, we still write
+ * out the index (unless locking fails).
+ */
+int repo_refresh_and_write_index(struct repository*, unsigned int refresh_flags, unsigned int write_flags, int gentle, const struct pathspec *, char *seen, const char *header_msg);
+
 struct cache_entry *refresh_cache_entry(struct index_state *, struct cache_entry *, unsigned int);
 
 void set_alternate_index_output(const char *);

diff --git a/read-cache.c b/read-cache.c
index 52ffa8a3139f2e427fadb7d233fb4910819becc9..7e646e06c2424aa2cb0a2c18fda114d80a9231aa 100644 (file)
--- a/read-cache.c
+++ b/read-cache.c
@@ -1472,6 +1472,27 @@ static void show_file(const char * fmt, const char * name, int in_porcelain,
        printf(fmt, name);
 }
 
+int repo_refresh_and_write_index(struct repository *repo,
+                                unsigned int refresh_flags,
+                                unsigned int write_flags,
+                                int gentle,
+                                const struct pathspec *pathspec,
+                                char *seen, const char *header_msg)
+{
+       struct lock_file lock_file = LOCK_INIT;
+       int fd, ret = 0;
+
+       fd = repo_hold_locked_index(repo, &lock_file, 0);
+       if (!gentle && fd < 0)
+               return -1;
+       if (refresh_index(repo->index, refresh_flags, pathspec, seen, header_msg))
+               ret = 1;
+       if (0 <= fd && write_locked_index(repo->index, &lock_file, COMMIT_LOCK | write_flags))
+               ret = -1;
+       return ret;
+}
+
+
 int refresh_index(struct index_state *istate, unsigned int flags,
                  const struct pathspec *pathspec,
                  char *seen, const char *header_msg)