Commit 55798fd1536f055fc23a760c41d679fc60cd2ead
2015-01-17T20:49:04
git_indexwriter: lock then write the index Introduce `git_indexwriter`, to allow us to lock the index while performing additional operations, then complete the write (or abort, unlocking the index).
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diff --git a/src/index.c b/src/index.c
index cbace36..58575fe 100644
--- a/src/index.c
+++ b/src/index.c
@@ -656,39 +656,15 @@ int git_index__changed_relative_to(
int git_index_write(git_index *index)
{
- git_filebuf file = GIT_FILEBUF_INIT;
+ git_indexwriter writer = GIT_INDEXWRITER_INIT;
int error;
- if (!index->index_file_path)
- return create_index_error(-1,
- "Failed to read index: The index is in-memory only");
-
- if (index_sort_if_needed(index, true) < 0)
- return -1;
- git_vector_sort(&index->reuc);
-
- if ((error = git_filebuf_open(
- &file, index->index_file_path, GIT_FILEBUF_HASH_CONTENTS, GIT_INDEX_FILE_MODE)) < 0) {
- if (error == GIT_ELOCKED)
- giterr_set(GITERR_INDEX, "The index is locked. This might be due to a concurrent or crashed process");
-
- return error;
- }
+ if ((error = git_indexwriter_init(&writer, index)) == 0)
+ error = git_indexwriter_commit(&writer);
- if ((error = write_index(index, &file)) < 0) {
- git_filebuf_cleanup(&file);
- return error;
- }
+ git_indexwriter_cleanup(&writer);
- if ((error = git_filebuf_commit(&file)) < 0)
- return error;
-
- if (git_futils_filestamp_check(&index->stamp, index->index_file_path) < 0)
- /* index could not be read from disk! */;
- else
- index->on_disk = 1;
-
- return 0;
+ return error;
}
const char * git_index_path(const git_index *index)
@@ -2686,3 +2662,59 @@ int git_index_snapshot_find(
{
return index_find_in_entries(out, entries, entry_srch, path, path_len, stage);
}
+
+int git_indexwriter_init(
+ git_indexwriter *writer,
+ git_index *index)
+{
+ int error;
+
+ writer->index = index;
+
+ if (!index->index_file_path)
+ return create_index_error(-1,
+ "Failed to write index: The index is in-memory only");
+
+ if ((error = git_filebuf_open(
+ &writer->file, index->index_file_path, GIT_FILEBUF_HASH_CONTENTS, GIT_INDEX_FILE_MODE)) < 0) {
+ if (error == GIT_ELOCKED)
+ giterr_set(GITERR_INDEX, "The index is locked. This might be due to a concurrent or crashed process");
+
+ return error;
+ }
+
+ return 0;
+}
+
+int git_indexwriter_commit(git_indexwriter *writer)
+{
+ int error;
+
+ if (index_sort_if_needed(writer->index, true) < 0)
+ return -1;
+
+ git_vector_sort(&writer->index->reuc);
+
+ if ((error = write_index(writer->index, &writer->file)) < 0) {
+ git_indexwriter_cleanup(writer);
+ return error;
+ }
+
+ if ((error = git_filebuf_commit(&writer->file)) < 0)
+ return error;
+
+ if ((error = git_futils_filestamp_check(
+ &writer->index->stamp, writer->index->index_file_path)) < 0) {
+ giterr_set(GITERR_OS, "Could not read index timestamp");
+ return -1;
+ }
+
+ writer->index->on_disk = 1;
+
+ return 0;
+}
+
+void git_indexwriter_cleanup(git_indexwriter *writer)
+{
+ git_filebuf_cleanup(&writer->file);
+}
diff --git a/src/index.h b/src/index.h
index 2eb93fb..d151f66 100644
--- a/src/index.h
+++ b/src/index.h
@@ -94,4 +94,22 @@ extern int git_index_snapshot_find(
const char *path, size_t path_len, int stage);
+typedef struct {
+ git_index *index;
+ git_filebuf file;
+} git_indexwriter;
+
+#define GIT_INDEXWRITER_INIT { NULL, GIT_FILEBUF_INIT }
+
+/* Lock the index for eventual writing. */
+extern int git_indexwriter_init(git_indexwriter *writer, git_index *index);
+
+/* Write the index and unlock it. */
+extern int git_indexwriter_commit(git_indexwriter *writer);
+
+/* Cleanup an index writing session, unlocking the file (if it is still
+ * locked and freeing any data structures.
+ */
+extern void git_indexwriter_cleanup(git_indexwriter *writer);
+
#endif
diff --git a/tests/index/tests.c b/tests/index/tests.c
index a63183e..4cf7051 100644
--- a/tests/index/tests.c
+++ b/tests/index/tests.c
@@ -677,3 +677,24 @@ void test_index_tests__reload_while_ignoring_case(void)
git_index_free(index);
}
+
+void test_index_tests__can_lock_index(void)
+{
+ git_index *index;
+ git_indexwriter one = GIT_INDEXWRITER_INIT,
+ two = GIT_INDEXWRITER_INIT;
+
+ cl_git_pass(git_index_open(&index, TEST_INDEX_PATH));
+ cl_git_pass(git_indexwriter_init(&one, index));
+
+ cl_git_fail_with(GIT_ELOCKED, git_indexwriter_init(&two, index));
+ cl_git_fail_with(GIT_ELOCKED, git_index_write(index));
+
+ cl_git_pass(git_indexwriter_commit(&one));
+
+ cl_git_pass(git_index_write(index));
+
+ git_indexwriter_cleanup(&one);
+ git_indexwriter_cleanup(&two);
+ git_index_free(index);
+}