From 4300f8442a276aa48d327b8371af9c2917bd3d5a Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Tue, 30 Mar 2021 13:10:48 +0000 Subject: [PATCH] sparse-index: implement ensure_full_index() 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 Signed-off-by: Junio C Hamano --- cache.h | 13 ++++++- read-cache.c | 9 +++++ sparse-index.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++++- 3 files changed, 118 insertions(+), 2 deletions(-) diff --git a/cache.h b/cache.h index bb317abc91..136dd496c9 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 +321,14 @@ 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 when sparse-directory + * entries exist. Requires sparse-checkout + * in cone mode. + */ + sparse_index : 1; struct hashmap name_hash; struct hashmap dir_hash; struct object_id oid; @@ -722,6 +731,8 @@ 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 1e9a50c6c7..dd3980c12b 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); } @@ -2273,6 +2276,12 @@ 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 82183ead56..7095378a1b 100644 --- a/sparse-index.c +++ b/sparse-index.c @@ -1,8 +1,104 @@ #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, 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; + struct strbuf base = STRBUF_INIT; + + 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; + + strbuf_setlen(&base, 0); + strbuf_add(&base, ce->name, strlen(ce->name)); + + read_tree_at(istate->repo, tree, &base, &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; + + strbuf_release(&base); + free(full); + + trace2_region_leave("index", "ensure_full_index", istate->repo); }