Commit 55798fd1 by Edward Thomson Committed by Edward Thomson

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).
parent 42f98a26
...@@ -656,39 +656,15 @@ int git_index__changed_relative_to( ...@@ -656,39 +656,15 @@ int git_index__changed_relative_to(
int git_index_write(git_index *index) int git_index_write(git_index *index)
{ {
git_filebuf file = GIT_FILEBUF_INIT; git_indexwriter writer = GIT_INDEXWRITER_INIT;
int error; int error;
if (!index->index_file_path) if ((error = git_indexwriter_init(&writer, index)) == 0)
return create_index_error(-1, error = git_indexwriter_commit(&writer);
"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( git_indexwriter_cleanup(&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;
}
if ((error = write_index(index, &file)) < 0) {
git_filebuf_cleanup(&file);
return error;
}
if ((error = git_filebuf_commit(&file)) < 0)
return error; 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;
} }
const char * git_index_path(const git_index *index) const char * git_index_path(const git_index *index)
...@@ -2686,3 +2662,59 @@ int git_index_snapshot_find( ...@@ -2686,3 +2662,59 @@ int git_index_snapshot_find(
{ {
return index_find_in_entries(out, entries, entry_srch, path, path_len, stage); 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);
}
...@@ -94,4 +94,22 @@ extern int git_index_snapshot_find( ...@@ -94,4 +94,22 @@ extern int git_index_snapshot_find(
const char *path, size_t path_len, int stage); 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 #endif
...@@ -677,3 +677,24 @@ void test_index_tests__reload_while_ignoring_case(void) ...@@ -677,3 +677,24 @@ void test_index_tests__reload_while_ignoring_case(void)
git_index_free(index); 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);
}
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