From 6e773527b6b03976cefbb0f9571bd40dd5995e6c Mon Sep 17 00:00:00 2001 From: Derrick Stolee Date: Tue, 30 Mar 2021 13:10:55 +0000 Subject: [PATCH] sparse-index: convert from full to sparse If we have a full index, then we can convert it to a sparse index by replacing directories outside of the sparse cone with sparse directory entries. The convert_to_sparse() method does this, when the situation is appropriate. For now, we avoid converting the index to a sparse index if: 1. the index is split. 2. the index is already sparse. 3. sparse-checkout is disabled. 4. sparse-checkout does not use cone mode. Finally, we currently limit the conversion to when the GIT_TEST_SPARSE_INDEX environment variable is enabled. A mode using Git config will be added in a later change. The trickiest thing about this conversion is that we might not be able to mark a directory as a sparse directory just because it is outside the sparse cone. There might be unmerged files within that directory, so we need to look for those. Also, if there is some strange reason why a file is not marked with CE_SKIP_WORKTREE, then we should give up on converting that directory. There is still hope that some of its subdirectories might be able to convert to sparse, so we keep looking deeper. The conversion process is assisted by the cache-tree extension. This is calculated from the full index if it does not already exist. We then abandon the cache-tree as it no longer applies to the newly-sparse index. Thus, this cache-tree will be recalculated in every sparse-full-sparse round-trip until we integrate the cache-tree extension with the sparse index. Some Git commands use the index after writing it. For example, 'git add' will update the index, then write it to disk, then read its entries to report information. To keep the in-memory index in a full state after writing, we re-expand it to a full one after the write. This is wasteful for commands that only write the index and do not read from it again, but that is only the case until we make those commands "sparse aware." We can compare the behavior of the sparse-index in t1092-sparse-checkout-compability.sh by using GIT_TEST_SPARSE_INDEX=1 when operating on the 'sparse-index' repo. We can also compare the two sparse repos directly, such as comparing their indexes (when expanded to full in the case of the 'sparse-index' repo). We also verify that the index is actually populated with sparse directory entries. The 'checkout and reset (mixed)' test is marked for failure when comparing a sparse repo to a full repo, but we can compare the two sparse-checkout cases directly to ensure that we are not changing the behavior when using a sparse index. Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano --- cache-tree.c | 3 + cache.h | 2 + read-cache.c | 26 ++++- sparse-index.c | 139 +++++++++++++++++++++++ sparse-index.h | 1 + t/t1092-sparse-checkout-compatibility.sh | 61 +++++++++- 6 files changed, 228 insertions(+), 4 deletions(-) diff --git a/cache-tree.c b/cache-tree.c index 2fb483d3c0..5f07a39e50 100644 --- a/cache-tree.c +++ b/cache-tree.c @@ -6,6 +6,7 @@ #include "object-store.h" #include "replace-object.h" #include "promisor-remote.h" +#include "sparse-index.h" #ifndef DEBUG_CACHE_TREE #define DEBUG_CACHE_TREE 0 @@ -442,6 +443,8 @@ int cache_tree_update(struct index_state *istate, int flags) if (i) return i; + ensure_full_index(istate); + if (!istate->cache_tree) istate->cache_tree = cache_tree(); diff --git a/cache.h b/cache.h index 8c4464420d..74b43aaa2b 100644 --- a/cache.h +++ b/cache.h @@ -251,6 +251,8 @@ static inline unsigned int create_ce_mode(unsigned int mode) { if (S_ISLNK(mode)) return S_IFLNK; + if (S_ISSPARSEDIR(mode)) + return S_IFDIR; if (S_ISDIR(mode) || S_ISGITLINK(mode)) return S_IFGITLINK; return S_IFREG | ce_permissions(mode); diff --git a/read-cache.c b/read-cache.c index b8f092d1b7..2410e6e0df 100644 --- a/read-cache.c +++ b/read-cache.c @@ -25,6 +25,7 @@ #include "fsmonitor.h" #include "thread-utils.h" #include "progress.h" +#include "sparse-index.h" /* Mask for the name length in ce_flags in the on-disk index */ @@ -1003,8 +1004,14 @@ int verify_path(const char *path, unsigned mode) c = *path++; if ((c == '.' && !verify_dotfile(path, mode)) || - is_dir_sep(c) || c == '\0') + is_dir_sep(c)) return 0; + /* + * allow terminating directory separators for + * sparse directory entries. + */ + if (c == '\0') + return S_ISDIR(mode); } else if (c == '\\' && protect_ntfs) { if (is_ntfs_dotgit(path)) return 0; @@ -3088,6 +3095,14 @@ static int do_write_locked_index(struct index_state *istate, struct lock_file *l unsigned flags) { int ret; + int was_full = !istate->sparse_index; + + ret = convert_to_sparse(istate); + + if (ret) { + warning(_("failed to convert to a sparse-index")); + return ret; + } /* * TODO trace2: replace "the_repository" with the actual repo instance @@ -3099,6 +3114,9 @@ static int do_write_locked_index(struct index_state *istate, struct lock_file *l trace2_region_leave_printf("index", "do_write_index", the_repository, "%s", get_lock_file_path(lock)); + if (was_full) + ensure_full_index(istate); + if (ret) return ret; if (flags & COMMIT_LOCK) @@ -3189,9 +3207,10 @@ static int write_shared_index(struct index_state *istate, struct tempfile **temp) { struct split_index *si = istate->split_index; - int ret; + int ret, was_full = !istate->sparse_index; move_cache_to_base_index(istate); + convert_to_sparse(istate); trace2_region_enter_printf("index", "shared/do_write_index", the_repository, "%s", get_tempfile_path(*temp)); @@ -3199,6 +3218,9 @@ static int write_shared_index(struct index_state *istate, trace2_region_leave_printf("index", "shared/do_write_index", the_repository, "%s", get_tempfile_path(*temp)); + if (was_full) + ensure_full_index(istate); + if (ret) return ret; ret = adjust_shared_perm(get_tempfile_path(*temp)); diff --git a/sparse-index.c b/sparse-index.c index 7095378a1b..619ff7c2e2 100644 --- a/sparse-index.c +++ b/sparse-index.c @@ -4,6 +4,145 @@ #include "tree.h" #include "pathspec.h" #include "trace2.h" +#include "cache-tree.h" +#include "config.h" +#include "dir.h" +#include "fsmonitor.h" + +static struct cache_entry *construct_sparse_dir_entry( + struct index_state *istate, + const char *sparse_dir, + struct cache_tree *tree) +{ + struct cache_entry *de; + + de = make_cache_entry(istate, S_IFDIR, &tree->oid, sparse_dir, 0, 0); + + de->ce_flags |= CE_SKIP_WORKTREE; + return de; +} + +/* + * Returns the number of entries "inserted" into the index. + */ +static int convert_to_sparse_rec(struct index_state *istate, + int num_converted, + int start, int end, + const char *ct_path, size_t ct_pathlen, + struct cache_tree *ct) +{ + int i, can_convert = 1; + int start_converted = num_converted; + enum pattern_match_result match; + int dtype; + struct strbuf child_path = STRBUF_INIT; + struct pattern_list *pl = istate->sparse_checkout_patterns; + + /* + * Is the current path outside of the sparse cone? + * Then check if the region can be replaced by a sparse + * directory entry (everything is sparse and merged). + */ + match = path_matches_pattern_list(ct_path, ct_pathlen, + NULL, &dtype, pl, istate); + if (match != NOT_MATCHED) + can_convert = 0; + + for (i = start; can_convert && i < end; i++) { + struct cache_entry *ce = istate->cache[i]; + + if (ce_stage(ce) || + !(ce->ce_flags & CE_SKIP_WORKTREE)) + can_convert = 0; + } + + if (can_convert) { + struct cache_entry *se; + se = construct_sparse_dir_entry(istate, ct_path, ct); + + istate->cache[num_converted++] = se; + return 1; + } + + for (i = start; i < end; ) { + int count, span, pos = -1; + const char *base, *slash; + struct cache_entry *ce = istate->cache[i]; + + /* + * Detect if this is a normal entry outside of any subtree + * entry. + */ + base = ce->name + ct_pathlen; + slash = strchr(base, '/'); + + if (slash) + pos = cache_tree_subtree_pos(ct, base, slash - base); + + if (pos < 0) { + istate->cache[num_converted++] = ce; + i++; + continue; + } + + strbuf_setlen(&child_path, 0); + strbuf_add(&child_path, ce->name, slash - ce->name + 1); + + span = ct->down[pos]->cache_tree->entry_count; + count = convert_to_sparse_rec(istate, + num_converted, i, i + span, + child_path.buf, child_path.len, + ct->down[pos]->cache_tree); + num_converted += count; + i += span; + } + + strbuf_release(&child_path); + return num_converted - start_converted; +} + +int convert_to_sparse(struct index_state *istate) +{ + if (istate->split_index || istate->sparse_index || + !core_apply_sparse_checkout || !core_sparse_checkout_cone) + return 0; + + /* + * For now, only create a sparse index with the + * GIT_TEST_SPARSE_INDEX environment variable. We will relax + * this once we have a proper way to opt-in (and later still, + * opt-out). + */ + if (!git_env_bool("GIT_TEST_SPARSE_INDEX", 0)) + return 0; + + if (!istate->sparse_checkout_patterns) { + istate->sparse_checkout_patterns = xcalloc(1, sizeof(struct pattern_list)); + if (get_sparse_checkout_patterns(istate->sparse_checkout_patterns) < 0) + return 0; + } + + if (!istate->sparse_checkout_patterns->use_cone_patterns) { + warning(_("attempting to use sparse-index without cone mode")); + return -1; + } + + if (cache_tree_update(istate, 0)) { + warning(_("unable to update cache-tree, staying full")); + return -1; + } + + remove_fsmonitor(istate); + + trace2_region_enter("index", "convert_to_sparse", istate->repo); + istate->cache_nr = convert_to_sparse_rec(istate, + 0, 0, istate->cache_nr, + "", 0, istate->cache_tree); + istate->drop_cache_tree = 1; + istate->sparse_index = 1; + trace2_region_leave("index", "convert_to_sparse", istate->repo); + return 0; +} static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce) { diff --git a/sparse-index.h b/sparse-index.h index 09a20d036c..64380e121d 100644 --- a/sparse-index.h +++ b/sparse-index.h @@ -3,5 +3,6 @@ struct index_state; void ensure_full_index(struct index_state *istate); +int convert_to_sparse(struct index_state *istate); #endif diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh index a1aea141c6..1e888d1951 100755 --- a/t/t1092-sparse-checkout-compatibility.sh +++ b/t/t1092-sparse-checkout-compatibility.sh @@ -2,6 +2,11 @@ test_description='compare full workdir to sparse workdir' +# The verify_cache_tree() check is not sparse-aware (yet). +# So, disable the check until that integration is complete. +GIT_TEST_CHECK_CACHE_TREE=0 +GIT_TEST_SPLIT_INDEX=0 + . ./test-lib.sh test_expect_success 'setup' ' @@ -121,7 +126,9 @@ run_on_all () { test_all_match () { run_on_all "$@" && test_cmp full-checkout-out sparse-checkout-out && - test_cmp full-checkout-err sparse-checkout-err + test_cmp full-checkout-out sparse-index-out && + test_cmp full-checkout-err sparse-checkout-err && + test_cmp full-checkout-err sparse-index-err } test_sparse_match () { @@ -130,6 +137,38 @@ test_sparse_match () { test_cmp sparse-checkout-err sparse-index-err } +test_expect_success 'sparse-index contents' ' + init_repos && + + test-tool -C sparse-index read-cache --table >cache && + for dir in folder1 folder2 x + do + TREE=$(git -C sparse-index rev-parse HEAD:$dir) && + grep "040000 tree $TREE $dir/" cache \ + || return 1 + done && + + GIT_TEST_SPARSE_INDEX=1 git -C sparse-index sparse-checkout set folder1 && + + test-tool -C sparse-index read-cache --table >cache && + for dir in deep folder2 x + do + TREE=$(git -C sparse-index rev-parse HEAD:$dir) && + grep "040000 tree $TREE $dir/" cache \ + || return 1 + done && + + GIT_TEST_SPARSE_INDEX=1 git -C sparse-index sparse-checkout set deep/deeper1 && + + test-tool -C sparse-index read-cache --table >cache && + for dir in deep/deeper2 folder1 folder2 x + do + TREE=$(git -C sparse-index rev-parse HEAD:$dir) && + grep "040000 tree $TREE $dir/" cache \ + || return 1 + done +' + test_expect_success 'expanded in-memory index matches full index' ' init_repos && test_sparse_match test-tool read-cache --expand --table @@ -137,6 +176,7 @@ test_expect_success 'expanded in-memory index matches full index' ' test_expect_success 'status with options' ' init_repos && + test_sparse_match ls && test_all_match git status --porcelain=v2 && test_all_match git status --porcelain=v2 -z -u && test_all_match git status --porcelain=v2 -uno && @@ -273,6 +313,17 @@ test_expect_failure 'checkout and reset (mixed)' ' test_all_match git reset update-folder2 ' +# Ensure that sparse-index behaves identically to +# sparse-checkout with a full index. +test_expect_success 'checkout and reset (mixed) [sparse]' ' + init_repos && + + test_sparse_match git checkout -b reset-test update-deep && + test_sparse_match git reset deepest && + test_sparse_match git reset update-folder1 && + test_sparse_match git reset update-folder2 +' + test_expect_success 'merge' ' init_repos && @@ -309,14 +360,20 @@ test_expect_success 'clean' ' test_all_match git status --porcelain=v2 && test_all_match git clean -f && test_all_match git status --porcelain=v2 && + test_sparse_match ls && + test_sparse_match ls folder1 && test_all_match git clean -xf && test_all_match git status --porcelain=v2 && + test_sparse_match ls && + test_sparse_match ls folder1 && test_all_match git clean -xdf && test_all_match git status --porcelain=v2 && + test_sparse_match ls && + test_sparse_match ls folder1 && - test_path_is_dir sparse-checkout/folder1 + test_sparse_match test_path_is_dir folder1 ' test_done