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-rw-r--r--sparse-index.c602
1 files changed, 602 insertions, 0 deletions
diff --git a/sparse-index.c b/sparse-index.c
new file mode 100644
index 0000000..3578feb
--- /dev/null
+++ b/sparse-index.c
@@ -0,0 +1,602 @@
+#include "git-compat-util.h"
+#include "environment.h"
+#include "gettext.h"
+#include "name-hash.h"
+#include "read-cache-ll.h"
+#include "repository.h"
+#include "sparse-index.h"
+#include "tree.h"
+#include "pathspec.h"
+#include "trace2.h"
+#include "cache-tree.h"
+#include "config.h"
+#include "dir.h"
+#include "fsmonitor-ll.h"
+
+struct modify_index_context {
+ struct index_state *write;
+ struct pattern_list *pl;
+};
+
+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;
+ struct strbuf child_path = STRBUF_INIT;
+
+ /*
+ * 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).
+ */
+ if (path_in_sparse_checkout(ct_path, istate))
+ can_convert = 0;
+
+ for (i = start; can_convert && i < end; i++) {
+ struct cache_entry *ce = istate->cache[i];
+
+ if (ce_stage(ce) ||
+ S_ISGITLINK(ce->ce_mode) ||
+ !(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 set_sparse_index_config(struct repository *repo, int enable)
+{
+ int res = repo_config_set_worktree_gently(repo,
+ "index.sparse",
+ enable ? "true" : "false");
+ prepare_repo_settings(repo);
+ repo->settings.sparse_index = enable;
+ return res;
+}
+
+static int index_has_unmerged_entries(struct index_state *istate)
+{
+ int i;
+ for (i = 0; i < istate->cache_nr; i++) {
+ if (ce_stage(istate->cache[i]))
+ return 1;
+ }
+
+ return 0;
+}
+
+int is_sparse_index_allowed(struct index_state *istate, int flags)
+{
+ if (!core_apply_sparse_checkout || !core_sparse_checkout_cone)
+ return 0;
+
+ if (!(flags & SPARSE_INDEX_MEMORY_ONLY)) {
+ int test_env;
+
+ /*
+ * The sparse index is not (yet) integrated with a split index.
+ */
+ if (istate->split_index || git_env_bool("GIT_TEST_SPLIT_INDEX", 0))
+ return 0;
+ /*
+ * The GIT_TEST_SPARSE_INDEX environment variable triggers the
+ * index.sparse config variable to be on.
+ */
+ test_env = git_env_bool("GIT_TEST_SPARSE_INDEX", -1);
+ if (test_env >= 0)
+ set_sparse_index_config(istate->repo, test_env);
+
+ /*
+ * Only convert to sparse if index.sparse is set.
+ */
+ prepare_repo_settings(istate->repo);
+ if (!istate->repo->settings.sparse_index)
+ return 0;
+ }
+
+ if (init_sparse_checkout_patterns(istate))
+ return 0;
+
+ /*
+ * We need cone-mode patterns to use sparse-index. If a user edits
+ * their sparse-checkout file manually, then we can detect during
+ * parsing that they are not actually using cone-mode patterns and
+ * hence we need to abort this conversion _without error_. Warnings
+ * already exist in the pattern parsing to inform the user of their
+ * bad patterns.
+ */
+ if (!istate->sparse_checkout_patterns->use_cone_patterns)
+ return 0;
+
+ return 1;
+}
+
+int convert_to_sparse(struct index_state *istate, int flags)
+{
+ /*
+ * If the index is already sparse, empty, or otherwise
+ * cannot be converted to sparse, do not convert.
+ */
+ if (istate->sparse_index == INDEX_COLLAPSED || !istate->cache_nr ||
+ !is_sparse_index_allowed(istate, flags))
+ return 0;
+
+ /*
+ * NEEDSWORK: If we have unmerged entries, then stay full.
+ * Unmerged entries prevent the cache-tree extension from working.
+ */
+ if (index_has_unmerged_entries(istate))
+ return 0;
+
+ if (!cache_tree_fully_valid(istate->cache_tree)) {
+ /* Clear and recompute the cache-tree */
+ cache_tree_free(&istate->cache_tree);
+
+ /*
+ * Silently return if there is a problem with the cache tree update,
+ * which might just be due to a conflict state in some entry.
+ *
+ * This might create new tree objects, so be sure to use
+ * WRITE_TREE_MISSING_OK.
+ */
+ if (cache_tree_update(istate, WRITE_TREE_MISSING_OK))
+ return 0;
+ }
+
+ 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);
+
+ /* Clear and recompute the cache-tree */
+ cache_tree_free(&istate->cache_tree);
+ cache_tree_update(istate, 0);
+
+ istate->fsmonitor_has_run_once = 0;
+ FREE_AND_NULL(istate->fsmonitor_dirty);
+ FREE_AND_NULL(istate->fsmonitor_last_update);
+
+ istate->sparse_index = INDEX_COLLAPSED;
+ 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)
+{
+ 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 modify_index_context *ctx = (struct modify_index_context *)context;
+ struct cache_entry *ce;
+ size_t len = base->len;
+
+ if (S_ISDIR(mode)) {
+ int dtype;
+ size_t baselen = base->len;
+ if (!ctx->pl)
+ return READ_TREE_RECURSIVE;
+
+ /*
+ * Have we expanded to a point outside of the sparse-checkout?
+ *
+ * Artificially pad the path name with a slash "/" to
+ * indicate it as a directory, and add an arbitrary file
+ * name ("-") so we can consider base->buf as a file name
+ * to match against the cone-mode patterns.
+ *
+ * If we compared just "path", then we would expand more
+ * than we should. Since every file at root is always
+ * included, we would expand every directory at root at
+ * least one level deep instead of using sparse directory
+ * entries.
+ */
+ strbuf_addstr(base, path);
+ strbuf_add(base, "/-", 2);
+
+ if (path_matches_pattern_list(base->buf, base->len,
+ NULL, &dtype,
+ ctx->pl, ctx->write)) {
+ strbuf_setlen(base, baselen);
+ return READ_TREE_RECURSIVE;
+ }
+
+ /*
+ * The path "{base}{path}/" is a sparse directory. Create the correct
+ * name for inserting the entry into the index.
+ */
+ strbuf_setlen(base, base->len - 1);
+ } else {
+ strbuf_addstr(base, path);
+ }
+
+ ce = make_cache_entry(ctx->write, mode, oid, base->buf, 0, 0);
+ ce->ce_flags |= CE_SKIP_WORKTREE | CE_EXTENDED;
+ set_index_entry(ctx->write, ctx->write->cache_nr++, ce);
+
+ strbuf_setlen(base, len);
+ return 0;
+}
+
+void expand_index(struct index_state *istate, struct pattern_list *pl)
+{
+ int i;
+ struct index_state *full;
+ struct strbuf base = STRBUF_INIT;
+ const char *tr_region;
+ struct modify_index_context ctx;
+
+ /*
+ * If the index is already full, then keep it full. We will convert
+ * it to a sparse index on write, if possible.
+ */
+ if (istate->sparse_index == INDEX_EXPANDED)
+ return;
+
+ /*
+ * If our index is sparse, but our new pattern set does not use
+ * cone mode patterns, then we need to expand the index before we
+ * continue. A NULL pattern set indicates a full expansion to a
+ * full index.
+ */
+ if (pl && !pl->use_cone_patterns) {
+ pl = NULL;
+ } else {
+ /*
+ * We might contract file entries into sparse-directory
+ * entries, and for that we will need the cache tree to
+ * be recomputed.
+ */
+ cache_tree_free(&istate->cache_tree);
+
+ /*
+ * If there is a problem creating the cache tree, then we
+ * need to expand to a full index since we cannot satisfy
+ * the current request as a sparse index.
+ */
+ if (cache_tree_update(istate, 0))
+ pl = NULL;
+ }
+
+ /*
+ * A NULL pattern set indicates we are expanding a full index, so
+ * we use a special region name that indicates the full expansion.
+ * This is used by test cases, but also helps to differentiate the
+ * two cases.
+ */
+ tr_region = pl ? "expand_index" : "ensure_full_index";
+ trace2_region_enter("index", tr_region, istate->repo);
+
+ /* initialize basics of new index */
+ full = xcalloc(1, sizeof(struct index_state));
+ memcpy(full, istate, sizeof(struct index_state));
+
+ /*
+ * This slightly-misnamed 'full' index might still be sparse if we
+ * are only modifying the list of sparse directories. This hinges
+ * on whether we have a non-NULL pattern list.
+ */
+ full->sparse_index = pl ? INDEX_PARTIALLY_SPARSE : INDEX_EXPANDED;
+
+ /* then change the necessary things */
+ full->cache_alloc = (3 * istate->cache_alloc) / 2;
+ full->cache_nr = 0;
+ ALLOC_ARRAY(full->cache, full->cache_alloc);
+
+ ctx.write = full;
+ ctx.pl = pl;
+
+ for (i = 0; i < istate->cache_nr; i++) {
+ struct cache_entry *ce = istate->cache[i];
+ struct tree *tree;
+ struct pathspec ps;
+ int dtype;
+
+ if (!S_ISSPARSEDIR(ce->ce_mode)) {
+ set_index_entry(full, full->cache_nr++, ce);
+ continue;
+ }
+
+ /* We now have a sparse directory entry. Should we expand? */
+ if (pl &&
+ path_matches_pattern_list(ce->name, ce->ce_namelen,
+ NULL, &dtype,
+ pl, istate) == NOT_MATCHED) {
+ 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, 0, &ps,
+ add_path_to_index, &ctx);
+
+ /* 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));
+ memcpy(&istate->dir_hash, &full->dir_hash, sizeof(full->dir_hash));
+ istate->sparse_index = pl ? INDEX_PARTIALLY_SPARSE : INDEX_EXPANDED;
+ free(istate->cache);
+ istate->cache = full->cache;
+ istate->cache_nr = full->cache_nr;
+ istate->cache_alloc = full->cache_alloc;
+ istate->fsmonitor_has_run_once = 0;
+ FREE_AND_NULL(istate->fsmonitor_dirty);
+ FREE_AND_NULL(istate->fsmonitor_last_update);
+
+ strbuf_release(&base);
+ free(full);
+
+ /* Clear and recompute the cache-tree */
+ cache_tree_free(&istate->cache_tree);
+ cache_tree_update(istate, 0);
+
+ trace2_region_leave("index", tr_region, istate->repo);
+}
+
+void ensure_full_index(struct index_state *istate)
+{
+ if (!istate)
+ BUG("ensure_full_index() must get an index!");
+ expand_index(istate, NULL);
+}
+
+void ensure_correct_sparsity(struct index_state *istate)
+{
+ /*
+ * If the index can be sparse, make it sparse. Otherwise,
+ * ensure the index is full.
+ */
+ if (is_sparse_index_allowed(istate, 0))
+ convert_to_sparse(istate, 0);
+ else
+ ensure_full_index(istate);
+}
+
+static int path_found(const char *path, const char **dirname, size_t *dir_len,
+ int *dir_found)
+{
+ struct stat st;
+ char *newdir;
+ char *tmp;
+
+ /*
+ * If dirname corresponds to a directory that doesn't exist, and this
+ * path starts with dirname, then path can't exist.
+ */
+ if (!*dir_found && !memcmp(path, *dirname, *dir_len))
+ return 0;
+
+ /*
+ * If path itself exists, return 1.
+ */
+ if (!lstat(path, &st))
+ return 1;
+
+ /*
+ * Otherwise, path does not exist so we'll return 0...but we'll first
+ * determine some info about its parent directory so we can avoid
+ * lstat calls for future cache entries.
+ */
+ newdir = strrchr(path, '/');
+ if (!newdir)
+ return 0; /* Didn't find a parent dir; just return 0 now. */
+
+ /*
+ * If path starts with directory (which we already lstat'ed and found),
+ * then no need to lstat parent directory again.
+ */
+ if (*dir_found && *dirname && memcmp(path, *dirname, *dir_len))
+ return 0;
+
+ /* Free previous dirname, and cache path's dirname */
+ *dirname = path;
+ *dir_len = newdir - path + 1;
+
+ tmp = xstrndup(path, *dir_len);
+ *dir_found = !lstat(tmp, &st);
+ free(tmp);
+
+ return 0;
+}
+
+void clear_skip_worktree_from_present_files(struct index_state *istate)
+{
+ const char *last_dirname = NULL;
+ size_t dir_len = 0;
+ int dir_found = 1;
+
+ int i;
+ int path_count[2] = {0, 0};
+ int restarted = 0;
+
+ if (!core_apply_sparse_checkout ||
+ sparse_expect_files_outside_of_patterns)
+ return;
+
+ trace2_region_enter("index", "clear_skip_worktree_from_present_files",
+ istate->repo);
+restart:
+ for (i = 0; i < istate->cache_nr; i++) {
+ struct cache_entry *ce = istate->cache[i];
+
+ if (ce_skip_worktree(ce)) {
+ path_count[restarted]++;
+ if (path_found(ce->name, &last_dirname, &dir_len, &dir_found)) {
+ if (S_ISSPARSEDIR(ce->ce_mode)) {
+ if (restarted)
+ BUG("ensure-full-index did not fully flatten?");
+ ensure_full_index(istate);
+ restarted = 1;
+ goto restart;
+ }
+ ce->ce_flags &= ~CE_SKIP_WORKTREE;
+ }
+ }
+ }
+
+ if (path_count[0])
+ trace2_data_intmax("index", istate->repo,
+ "sparse_path_count", path_count[0]);
+ if (restarted)
+ trace2_data_intmax("index", istate->repo,
+ "sparse_path_count_full", path_count[1]);
+ trace2_region_leave("index", "clear_skip_worktree_from_present_files",
+ istate->repo);
+}
+
+/*
+ * This static global helps avoid infinite recursion between
+ * expand_to_path() and index_file_exists().
+ */
+static int in_expand_to_path = 0;
+
+void expand_to_path(struct index_state *istate,
+ const char *path, size_t pathlen, int icase)
+{
+ struct strbuf path_mutable = STRBUF_INIT;
+ size_t substr_len;
+
+ /* prevent extra recursion */
+ if (in_expand_to_path)
+ return;
+
+ if (!istate->sparse_index)
+ return;
+
+ in_expand_to_path = 1;
+
+ /*
+ * We only need to actually expand a region if the
+ * following are both true:
+ *
+ * 1. 'path' is not already in the index.
+ * 2. Some parent directory of 'path' is a sparse directory.
+ */
+
+ if (index_file_exists(istate, path, pathlen, icase))
+ goto cleanup;
+
+ strbuf_add(&path_mutable, path, pathlen);
+ strbuf_addch(&path_mutable, '/');
+
+ /* Check the name hash for all parent directories */
+ substr_len = 0;
+ while (substr_len < pathlen) {
+ char temp;
+ char *replace = strchr(path_mutable.buf + substr_len, '/');
+
+ if (!replace)
+ break;
+
+ /* replace the character _after_ the slash */
+ replace++;
+ temp = *replace;
+ *replace = '\0';
+ if (index_file_exists(istate, path_mutable.buf,
+ path_mutable.len, icase)) {
+ /*
+ * We found a parent directory in the name-hash
+ * hashtable, because only sparse directory entries
+ * have a trailing '/' character. Since "path" wasn't
+ * in the index, perhaps it exists within this
+ * sparse-directory. Expand accordingly.
+ */
+ ensure_full_index(istate);
+ break;
+ }
+
+ *replace = temp;
+ substr_len = replace - path_mutable.buf;
+ }
+
+cleanup:
+ strbuf_release(&path_mutable);
+ in_expand_to_path = 0;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-02 13:37:34 +0000