diff options
| -rw-r--r-- | include/git2/index.h | 12 | ||||
| -rw-r--r-- | src/index.c | 47 | ||||
| -rw-r--r-- | src/index.h | 1 |
3 files changed, 55 insertions, 5 deletions
diff --git a/include/git2/index.h b/include/git2/index.h index 49bbe1614..7caf3ed78 100644 --- a/include/git2/index.h +++ b/include/git2/index.h @@ -274,6 +274,18 @@ GIT_EXTERN(int) git_index_write(git_index *index); GIT_EXTERN(const char *) git_index_path(const git_index *index); /** + * Get the checksum of the index + * + * This checksum is the SHA-1 hash over the index file (except the + * last 20 bytes which are the checksum itself). In cases where the + * index does not exist on-disk, it will be zeroed out. + * + * @param index an existing index object + * @return a pointer to the checksum of the index + */ +GIT_EXTERN(const git_oid *) git_index_checksum(git_index *index); + +/** * Read a tree into the index file with stats * * The current index contents will be replaced by the specified tree. diff --git a/src/index.c b/src/index.c index a931f048a..ba101ea14 100644 --- a/src/index.c +++ b/src/index.c @@ -116,7 +116,7 @@ static int read_header(struct index_header *dest, const void *buffer); static int parse_index(git_index *index, const char *buffer, size_t buffer_size); static bool is_index_extended(git_index *index); -static int write_index(git_index *index, git_filebuf *file); +static int write_index(git_oid *checksum, git_index *index, git_filebuf *file); static void index_entry_free(git_index_entry *entry); static void index_entry_reuc_free(git_index_reuc_entry *reuc); @@ -598,6 +598,38 @@ int git_index_caps(const git_index *index) (index->no_symlinks ? GIT_INDEXCAP_NO_SYMLINKS : 0)); } +const git_oid *git_index_checksum(git_index *index) +{ + return &index->checksum; +} + +/** + * Returns 1 for changed, 0 for not changed and <0 for errors + */ +static int compare_checksum(git_index *index) +{ + int fd, error; + ssize_t bytes_read; + git_oid checksum = {{ 0 }}; + + if ((fd = p_open(index->index_file_path, O_RDONLY)) < 0) + return fd; + + if ((error = p_lseek(fd, -20, SEEK_END)) < 0) { + p_close(fd); + giterr_set(GITERR_OS, "failed to seek to end of file"); + return -1; + } + + bytes_read = p_read(fd, &checksum, GIT_OID_RAWSZ); + p_close(fd); + + if (bytes_read < 0) + return -1; + + return !!git_oid_cmp(&checksum, &index->checksum); +} + int git_index_read(git_index *index, int force) { int error = 0, updated; @@ -616,8 +648,8 @@ int git_index_read(git_index *index, int force) return 0; } - updated = git_futils_filestamp_check(&stamp, index->index_file_path); - if (updated < 0) { + if ((updated = git_futils_filestamp_check(&stamp, index->index_file_path) < 0) || + ((updated = compare_checksum(index)) < 0)) { giterr_set( GITERR_INDEX, "Failed to read index: '%s' no longer exists", @@ -2092,6 +2124,8 @@ static int parse_index(git_index *index, const char *buffer, size_t buffer_size) goto done; } + git_oid_cpy(&index->checksum, &checksum_calculated); + #undef seek_forward /* Entries are stored case-sensitively on disk, so re-sort now if @@ -2355,7 +2389,7 @@ static int write_tree_extension(git_index *index, git_filebuf *file) return error; } -static int write_index(git_index *index, git_filebuf *file) +static int write_index(git_oid *checksum, git_index *index, git_filebuf *file) { git_oid hash_final; struct index_header header; @@ -2391,6 +2425,7 @@ static int write_index(git_index *index, git_filebuf *file) /* get out the hash for all the contents we've appended to the file */ git_filebuf_hash(&hash_final, file); + git_oid_cpy(checksum, &hash_final); /* write it at the end of the file */ return git_filebuf_write(file, hash_final.id, GIT_OID_RAWSZ); @@ -2953,6 +2988,7 @@ int git_indexwriter_init_for_operation( int git_indexwriter_commit(git_indexwriter *writer) { int error; + git_oid checksum = {{ 0 }}; if (!writer->should_write) return 0; @@ -2962,7 +2998,7 @@ int git_indexwriter_commit(git_indexwriter *writer) git_vector_sort(&writer->index->reuc); - if ((error = write_index(writer->index, &writer->file)) < 0) { + if ((error = write_index(&checksum, writer->index, &writer->file)) < 0) { git_indexwriter_cleanup(writer); return error; } @@ -2977,6 +3013,7 @@ int git_indexwriter_commit(git_indexwriter *writer) } writer->index->on_disk = 1; + git_oid_cpy(&writer->index->checksum, &checksum); git_index_free(writer->index); writer->index = NULL; diff --git a/src/index.h b/src/index.h index 0f6f4e86e..615d703c4 100644 --- a/src/index.h +++ b/src/index.h @@ -22,6 +22,7 @@ struct git_index { char *index_file_path; git_futils_filestamp stamp; + git_oid checksum; /* checksum at the end of the file */ git_vector entries; |