From: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
We will mark an in-memory index_state as having sparse directory entries
with the sparse_index bit. These currently cannot exist, but we will add
a mechanism for collapsing a full index to a sparse one in a later
change. That will happen at write time, so we must first allow parsing
the format before writing it.
Commands or methods that require a full index in order to operate can
call ensure_full_index() to expand that index in-memory. This requires
parsing trees using that index's repository.
Sparse directory entries have a specific 'ce_mode' value. The macro
S_ISSPARSEDIR(ce->ce_mode) can check if a cache_entry 'ce' has this type.
This ce_mode is not possible with the existing index formats, so we don't
also verify all properties of a sparse-directory entry, which are:
1. ce->ce_mode == 0040000
2. ce->flags & CE_SKIP_WORKTREE is true
3. ce->name[ce->namelen - 1] == '/' (ends in dir separator)
4. ce->oid references a tree object.
These are all semi-enforced in ensure_full_index() to some extent. Any
deviation will cause a warning at minimum or a failure in the worst
case.
Signed-off-by: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
---
cache.h | 7 +++-
read-cache.c | 9 +++++
sparse-index.c | 95 +++++++++++++++++++++++++++++++++++++++++++++++++-
3 files changed, 109 insertions(+), 2 deletions(-)
diff --git a/cache.h b/cache.h
index d92814961405..1336c8d7435e 100644
--- a/cache.h
+++ b/cache.h
@@ -204,6 +204,8 @@ struct cache_entry {
#error "CE_EXTENDED_FLAGS out of range"
#endif
+#define S_ISSPARSEDIR(m) ((m) == S_IFDIR)
+
/* Forward structure decls */
struct pathspec;
struct child_process;
@@ -319,7 +321,8 @@ struct index_state {
drop_cache_tree : 1,
updated_workdir : 1,
updated_skipworktree : 1,
- fsmonitor_has_run_once : 1;
+ fsmonitor_has_run_once : 1,
+ sparse_index : 1;
struct hashmap name_hash;
struct hashmap dir_hash;
struct object_id oid;
@@ -722,6 +725,8 @@ int read_index_from(struct index_state *, const char *path,
const char *gitdir);
int is_index_unborn(struct index_state *);
+void ensure_full_index(struct index_state *istate);
+
/* For use with `write_locked_index()`. */
#define COMMIT_LOCK (1 << 0)
#define SKIP_IF_UNCHANGED (1 << 1)
diff --git a/read-cache.c b/read-cache.c
index 29144cf879e7..97dbf2434f30 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -101,6 +101,9 @@ static const char *alternate_index_output;
static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
{
+ if (S_ISSPARSEDIR(ce->ce_mode))
+ istate->sparse_index = 1;
+
istate->cache[nr] = ce;
add_name_hash(istate, ce);
}
@@ -2255,6 +2258,12 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)
trace2_data_intmax("index", the_repository, "read/cache_nr",
istate->cache_nr);
+ if (!istate->repo)
+ istate->repo = the_repository;
+ prepare_repo_settings(istate->repo);
+ if (istate->repo->settings.command_requires_full_index)
+ ensure_full_index(istate);
+
return istate->cache_nr;
unmap:
diff --git a/sparse-index.c b/sparse-index.c
index 82183ead563b..316cb949b74b 100644
--- a/sparse-index.c
+++ b/sparse-index.c
@@ -1,8 +1,101 @@
#include "cache.h"
#include "repository.h"
#include "sparse-index.h"
+#include "tree.h"
+#include "pathspec.h"
+#include "trace2.h"
+
+static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
+{
+ ALLOC_GROW(istate->cache, nr + 1, istate->cache_alloc);
+
+ istate->cache[nr] = ce;
+ add_name_hash(istate, ce);
+}
+
+static int add_path_to_index(const struct object_id *oid,
+ struct strbuf *base, const char *path,
+ unsigned int mode, int stage, void *context)
+{
+ struct index_state *istate = (struct index_state *)context;
+ struct cache_entry *ce;
+ size_t len = base->len;
+
+ if (S_ISDIR(mode))
+ return READ_TREE_RECURSIVE;
+
+ strbuf_addstr(base, path);
+
+ ce = make_cache_entry(istate, mode, oid, base->buf, 0, 0);
+ ce->ce_flags |= CE_SKIP_WORKTREE;
+ set_index_entry(istate, istate->cache_nr++, ce);
+
+ strbuf_setlen(base, len);
+ return 0;
+}
void ensure_full_index(struct index_state *istate)
{
- /* intentionally left blank */
+ int i;
+ struct index_state *full;
+
+ if (!istate || !istate->sparse_index)
+ return;
+
+ if (!istate->repo)
+ istate->repo = the_repository;
+
+ trace2_region_enter("index", "ensure_full_index", istate->repo);
+
+ /* initialize basics of new index */
+ full = xcalloc(1, sizeof(struct index_state));
+ memcpy(full, istate, sizeof(struct index_state));
+
+ /* then change the necessary things */
+ full->sparse_index = 0;
+ full->cache_alloc = (3 * istate->cache_alloc) / 2;
+ full->cache_nr = 0;
+ ALLOC_ARRAY(full->cache, full->cache_alloc);
+
+ for (i = 0; i < istate->cache_nr; i++) {
+ struct cache_entry *ce = istate->cache[i];
+ struct tree *tree;
+ struct pathspec ps;
+
+ if (!S_ISSPARSEDIR(ce->ce_mode)) {
+ set_index_entry(full, full->cache_nr++, ce);
+ continue;
+ }
+ if (!(ce->ce_flags & CE_SKIP_WORKTREE))
+ warning(_("index entry is a directory, but not sparse (%08x)"),
+ ce->ce_flags);
+
+ /* recursively walk into cd->name */
+ tree = lookup_tree(istate->repo, &ce->oid);
+
+ memset(&ps, 0, sizeof(ps));
+ ps.recursive = 1;
+ ps.has_wildcard = 1;
+ ps.max_depth = -1;
+
+ read_tree_recursive(istate->repo, tree,
+ ce->name, strlen(ce->name),
+ 0, &ps,
+ add_path_to_index, full);
+
+ /* free directory entries. full entries are re-used */
+ discard_cache_entry(ce);
+ }
+
+ /* Copy back into original index. */
+ memcpy(&istate->name_hash, &full->name_hash, sizeof(full->name_hash));
+ istate->sparse_index = 0;
+ free(istate->cache);
+ istate->cache = full->cache;
+ istate->cache_nr = full->cache_nr;
+ istate->cache_alloc = full->cache_alloc;
+
+ free(full);
+
+ trace2_region_leave("index", "ensure_full_index", istate->repo);
}
--
gitgitgadget
