From c3da9f062d8c202b2a66b289b3570ac9fe6fc02d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Carlos=20Mart=C3=ADn=20Nieto?= Date: Thu, 21 Jul 2011 22:55:20 +0200 Subject: [PATCH 1/3] Add git_futils_readbuffer_updated MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This extends the git_fuitls_readbuffer function to only read in if the file's modification date is later than the given one. Some code paths want to check a file's modification date in order to decide whether they should read it or not. If they do want to read it, another stat call is done by futils. This function combines these two operations so we avoid one stat call each time we read a new or updated file. The git_futils_readbuffer functions is now a wrapper around the new function. Signed-off-by: Carlos Martín Nieto --- src/fileops.c | 43 +++++++++++++++++++++++++++++++++++-------- src/fileops.h | 1 + 2 files changed, 36 insertions(+), 8 deletions(-) diff --git a/src/fileops.c b/src/fileops.c index 2d1915a96..c7fddc623 100644 --- a/src/fileops.c +++ b/src/fileops.c @@ -141,23 +141,40 @@ git_off_t git_futils_filesize(git_file fd) return sb.st_size; } -int git_futils_readbuffer(git_fbuffer *obj, const char *path) +int git_futils_readbuffer_updated(git_fbuffer *obj, const char *path, time_t *mtime, int *updated) { git_file fd; size_t len; - git_off_t size; + struct stat st; unsigned char *buff; assert(obj && path && *path); - if ((fd = p_open(path, O_RDONLY)) < 0) - return git__throw(GIT_ERROR, "Failed to open %s for reading", path); + if (updated != NULL) + *updated = 0; - if (((size = git_futils_filesize(fd)) < 0) || !git__is_sizet(size+1)) { - p_close(fd); + if (p_stat(path, &st) < 0) + return git__throw(GIT_ENOTFOUND, "Failed to stat file %s", path); + + if (S_ISDIR(st.st_mode)) + return git__throw(GIT_ERROR, "Can't read a dir into a buffer"); + + /* + * If we were given a time, we only want to read the file if it + * has been modified. + */ + if (mtime != NULL && *mtime >= st.st_mtime) + return GIT_SUCCESS; + + if (mtime != NULL) + *mtime = st.st_mtime; + if (!git__is_sizet(st.st_size+1)) return git__throw(GIT_ERROR, "Failed to read file `%s`. An error occured while calculating its size", path); - } - len = (size_t) size; + + len = (size_t) st.st_size; + + if ((fd = p_open(path, O_RDONLY)) < 0) + return git__throw(GIT_EOSERR, "Failed to open %s for reading", path); if ((buff = git__malloc(len + 1)) == NULL) { p_close(fd); @@ -173,12 +190,22 @@ int git_futils_readbuffer(git_fbuffer *obj, const char *path) p_close(fd); + if (mtime != NULL) + *mtime = st.st_mtime; + if (updated != NULL) + *updated = 1; + obj->data = buff; obj->len = len; return GIT_SUCCESS; } +int git_futils_readbuffer(git_fbuffer *obj, const char *path) +{ + return git_futils_readbuffer_updated(obj, path, NULL, NULL); +} + void git_futils_freebuffer(git_fbuffer *obj) { assert(obj); diff --git a/src/fileops.h b/src/fileops.h index f1c169c3a..84c35e41b 100644 --- a/src/fileops.h +++ b/src/fileops.h @@ -25,6 +25,7 @@ typedef struct { /* file io buffer */ } git_fbuffer; extern int git_futils_readbuffer(git_fbuffer *obj, const char *path); +extern int git_futils_readbuffer_updated(git_fbuffer *obj, const char *path, time_t *mtime, int *updated); extern void git_futils_freebuffer(git_fbuffer *obj); /** From c498232812a34925fe280bd16938ba7ecf2cd6cc Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Carlos=20Mart=C3=ADn=20Nieto?= Date: Sat, 23 Jul 2011 12:09:51 +0200 Subject: [PATCH 2/3] refs: don't stat so much MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In reference_read we stat a file and then call futils which stats it again. Use git_futils_readbuffer_updated to avoid the extra stat call. This introduces another parameter which is used to tell the caller whether the file was read or not. Modify the callers to take advantage of this new feature. This change removes ~140 stat calls from the test suite. Signed-off-by: Carlos Martín Nieto --- src/refs.c | 98 +++++++++++++++++++++++++----------------------------- 1 file changed, 45 insertions(+), 53 deletions(-) diff --git a/src/refs.c b/src/refs.c index 8022c2b2a..3d560f9d5 100644 --- a/src/refs.c +++ b/src/refs.c @@ -59,7 +59,7 @@ static uint32_t reftable_hash(const void *key, int hash_id) static void reference_free(git_reference *reference); static int reference_create(git_reference **ref_out, git_repository *repo, const char *name, git_rtype type); -static int reference_read(git_fbuffer *file_content, time_t *mtime, const char *repo_path, const char *ref_name); +static int reference_read(git_fbuffer *file_content, time_t *mtime, const char *repo_path, const char *ref_name, int *updated); /* loose refs */ static int loose_parse_symbolic(git_reference *ref, git_fbuffer *file_content); @@ -150,23 +150,16 @@ cleanup: return error == GIT_SUCCESS ? GIT_SUCCESS : git__rethrow(error, "Failed to create reference"); } -static int reference_read(git_fbuffer *file_content, time_t *mtime, const char *repo_path, const char *ref_name) +static int reference_read(git_fbuffer *file_content, time_t *mtime, const char *repo_path, const char *ref_name, int *updated) { - struct stat st; char path[GIT_PATH_MAX]; + assert(file_content && repo_path && ref_name); + /* Determine the full path of the file */ git_path_join(path, repo_path, ref_name); - if (p_stat(path, &st) < 0 || S_ISDIR(st.st_mode)) - return git__throw(GIT_ENOTFOUND, - "Cannot read reference file '%s'", ref_name); - - if (mtime) - *mtime = st.st_mtime; - - if (file_content) - return git_futils_readbuffer(file_content, path); + return git_futils_readbuffer_updated(file_content, path, mtime, updated); return GIT_SUCCESS; } @@ -179,24 +172,26 @@ static int reference_read(git_fbuffer *file_content, time_t *mtime, const char * *****************************************/ static int loose_update(git_reference *ref) { - int error; - time_t ref_time; + int error, updated; git_fbuffer ref_file = GIT_FBUFFER_INIT; if (ref->type & GIT_REF_PACKED) return packed_load(ref->owner); - error = reference_read(NULL, &ref_time, ref->owner->path_repository, ref->name); +/* error = reference_read(NULL, &ref_time, ref->owner->path_repository, ref->name); if (error < GIT_SUCCESS) goto cleanup; if (ref_time == ref->mtime) return GIT_SUCCESS; - - error = reference_read(&ref_file, &ref->mtime, ref->owner->path_repository, ref->name); +*/ + error = reference_read(&ref_file, &ref->mtime, ref->owner->path_repository, ref->name, &updated); if (error < GIT_SUCCESS) goto cleanup; + if (!updated) + goto cleanup; + if (ref->type == GIT_REF_SYMBOLIC) error = loose_parse_symbolic(ref, &ref_file); else if (ref->type == GIT_REF_OID) @@ -205,9 +200,9 @@ static int loose_update(git_reference *ref) error = git__throw(GIT_EOBJCORRUPTED, "Invalid reference type (%d) for loose reference", ref->type); - git_futils_freebuffer(&ref_file); cleanup: + git_futils_freebuffer(&ref_file); if (error != GIT_SUCCESS) { reference_free(ref); git_hashtable_remove(ref->owner->references.loose_cache, ref->name); @@ -311,11 +306,11 @@ static int loose_lookup( int error = GIT_SUCCESS; git_fbuffer ref_file = GIT_FBUFFER_INIT; git_reference *ref = NULL; - time_t ref_time; + time_t ref_time = 0; *ref_out = NULL; - error = reference_read(&ref_file, &ref_time, repo->path_repository, name); + error = reference_read(&ref_file, &ref_time, repo->path_repository, name, NULL); if (error < GIT_SUCCESS) goto cleanup; @@ -500,53 +495,49 @@ cleanup: static int packed_load(git_repository *repo) { - int error = GIT_SUCCESS; + int error = GIT_SUCCESS, updated; git_fbuffer packfile = GIT_FBUFFER_INIT; const char *buffer_start, *buffer_end; git_refcache *ref_cache = &repo->references; - /* already loaded */ - if (repo->references.packfile != NULL) { - time_t packed_time; - - /* check if we can read the time of the index; - * if we can read it and it matches the time of the - * index we had previously loaded, we don't need to do - * anything else. - * - * if we cannot load the time (e.g. the packfile - * has disappeared) or the time is different, we - * have to reload the packfile */ - - if (!reference_read(NULL, &packed_time, repo->path_repository, GIT_PACKEDREFS_FILE) && - packed_time == ref_cache->packfile_time) - return GIT_SUCCESS; - - git_hashtable_clear(repo->references.packfile); - } else { + /* First we make sure we have allocated the hash table */ + if (ref_cache->packfile == NULL) { ref_cache->packfile = git_hashtable_alloc( default_table_size, reftable_hash, (git_hash_keyeq_ptr)strcmp); - if (ref_cache->packfile == NULL) - return GIT_ENOMEM; + if (ref_cache->packfile == NULL) { + error = GIT_ENOMEM; + goto cleanup; + } } - /* read the packfile from disk; - * store its modification time to check for future reloads */ - error = reference_read( - &packfile, - &ref_cache->packfile_time, - repo->path_repository, - GIT_PACKEDREFS_FILE); + error = reference_read(&packfile, &ref_cache->packfile_time, + repo->path_repository, GIT_PACKEDREFS_FILE, &updated); - /* there is no packfile on disk; that's ok */ - if (error == GIT_ENOTFOUND) + /* + * If we couldn't find the file, we need to clear the table and + * return. On any other error, we return that error. If everything + * went fine and the file wasn't updated, then there's nothing new + * for us here, so just return. Anything else means we need to + * refresh the packed refs. + */ + if (error == GIT_ENOTFOUND) { + git_hashtable_clear(ref_cache->packfile); return GIT_SUCCESS; + } else if (error < GIT_SUCCESS) { + return git__rethrow(error, "Failed to read packed refs"); + } else if (!updated) { + return GIT_SUCCESS; + } - if (error < GIT_SUCCESS) - goto cleanup; + /* + * At this point, we want to refresh the packed refs. We already + * have the contents in our buffer. + */ + + git_hashtable_clear(ref_cache->packfile); buffer_start = (const char *)packfile.data; buffer_end = (const char *)(buffer_start) + packfile.len; @@ -1624,6 +1615,7 @@ int git_repository__refcache_init(git_refcache *refs) /* packfile loaded lazily */ refs->packfile = NULL; + refs->packfile_time = 0; return (refs->loose_cache) ? GIT_SUCCESS : GIT_ENOMEM; } From 7db40d450de401100922b023ec5e687bc1a6d4d5 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Carlos=20Mart=C3=ADn=20Nieto?= Date: Sat, 23 Jul 2011 13:57:06 +0200 Subject: [PATCH 3/3] index: use git_futils_readbuffer_updated MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This helps readability a bit as well. Signed-off-by: Carlos Martín Nieto --- src/index.c | 27 +++++++++++---------------- 1 file changed, 11 insertions(+), 16 deletions(-) diff --git a/src/index.c b/src/index.c index 6390da3d7..5afe44954 100644 --- a/src/index.c +++ b/src/index.c @@ -248,8 +248,9 @@ void git_index_clear(git_index *index) int git_index_read(git_index *index) { - struct stat indexst; - int error = GIT_SUCCESS; + int error = GIT_SUCCESS, updated; + git_fbuffer buffer = GIT_FBUFFER_INIT; + time_t mtime; assert(index->index_file_path); @@ -259,30 +260,24 @@ int git_index_read(git_index *index) return GIT_SUCCESS; } - if (p_stat(index->index_file_path, &indexst) < 0) - return git__throw(GIT_EOSERR, "Failed to read index. %s does not exist or is corrupted", index->index_file_path); - - if (!S_ISREG(indexst.st_mode)) - return git__throw(GIT_ENOTFOUND, "Failed to read index. %s is not an index file", index->index_file_path); - - if (indexst.st_mtime != index->last_modified) { - - git_fbuffer buffer; - - if ((error = git_futils_readbuffer(&buffer, index->index_file_path)) < GIT_SUCCESS) - return git__rethrow(error, "Failed to read index"); + /* We don't want to update the mtime if we fail to parse the index */ + mtime = index->last_modified; + error = git_futils_readbuffer_updated(&buffer, index->index_file_path, &mtime, &updated); + if (error < GIT_SUCCESS) + return git__rethrow(error, "Failed to read index"); + if (updated) { git_index_clear(index); error = parse_index(index, buffer.data, buffer.len); if (error == GIT_SUCCESS) - index->last_modified = indexst.st_mtime; + index->last_modified = mtime; git_futils_freebuffer(&buffer); } if (error < GIT_SUCCESS) - return git__rethrow(error, "Failed to read index"); + return git__rethrow(error, "Failed to parse index"); return error; }