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42824db113
Blame and "git log --stat" recover hunk coordinates by diffing blob pairs, and recompute them on every run. Add a cache of those coordinates at $GIT_DIR/objects/info/diff-hunks, beside the commit-graph, so a later run can look them up instead of decompressing the blobs and running xdiff again. The store is a single chunk-format file (see gitformat-chunk(5)): an 8-byte header, a DHIX index of fixed-size entries sorted by key, a DHDT segment of hunk records, and a trailing hash checksum. An entry is keyed by the two blob object ids and the xdl_opts the pair was diffed under, so a stored result is served only where that exact key recurs, independent of path. A zero-context diff trims unchanged lines from hunk edges and can pick a different but equally valid set of hunks than an untrimmed diff, so a recording caller stores a pair only when its trimmed and untrimmed diffs are identical; such an entry answers any consumer at any context, and the rare divergent pair is always computed. Identical hunk blocks are interned once and shared across keys. The library provides a reader (repo_diff_hunks_store and _replay, gated by core.diffHunks), loaded once and cached on the object database as the commit-graph is, and a writer that accumulates entries and flushes them in one atomic pass. An absent, corrupt, or disabled store reads as all misses. A record with no hunks is invalid too: replaying it would claim the pair equivalent, which the store never asserts, so it reads as a miss. Ordinary reads are diagnostic-free. Loading parses the chunk table through read_table_of_contents_quiet(), new in chunk-format, which prints nothing on a malformed table and takes the repository's hash algorithm rather than the_hash_algo, so the file is bounds-checked under the algorithm it is keyed by. The flush closes the repository's mmapped store and forgets that loading was attempted before committing the lockfile. A warming run that also reads may hold the file it is replacing mapped, and the rename must not land on a live mapping, which Windows refuses; a read after the flush then observes the committed file. commit-graph closes its graph before committing for the same reason. Writing is off by default, enabled per run by GIT_DIFF_HUNKS_WRITE or persistently by diffHunks.write, the environment winning. A writer seeds from the existing store, so a flush merges rather than replaces. The seed's checksum is verified first: a corrupt store is discarded, not rewritten with a fresh checksum verify could no longer catch. An entry that fails the shared diff_provider_check_hunk() or names no blob is dropped with a warning, since it would only ever read as a miss. A seed that discarded or dropped anything forces the flush even when the warming run computed nothing new. The writer fsyncs through a new diff-hunks core.fsync component. "git diff-hunks" inspects and manages the file: "verify" checks the checksum, chunk table, sort order, entry bounds, and every entry's hunk sequence against that shared check, so a store whose entries could only read as misses fails verify; "clear" removes the file. Later patches wire the readers and the writer into the diff and blame paths. Signed-off-by: Michael Montalbo <mmontalbo@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
98 lines
2.9 KiB
C
98 lines
2.9 KiB
C
#ifndef REPO_SETTINGS_H
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#define REPO_SETTINGS_H
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struct fsmonitor_settings;
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struct repository;
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enum untracked_cache_setting {
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UNTRACKED_CACHE_KEEP,
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UNTRACKED_CACHE_REMOVE,
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UNTRACKED_CACHE_WRITE,
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};
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enum fetch_negotiation_setting {
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FETCH_NEGOTIATION_CONSECUTIVE,
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FETCH_NEGOTIATION_SKIPPING,
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FETCH_NEGOTIATION_NOOP,
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};
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struct repo_settings {
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int initialized;
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int core_commit_graph;
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int commit_graph_generation_version;
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int commit_graph_changed_paths_version;
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int core_diff_hunks;
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int gc_write_commit_graph;
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int fetch_write_commit_graph;
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int command_requires_full_index;
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int sparse_index;
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int pack_read_reverse_index;
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int pack_use_bitmap_boundary_traversal;
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int pack_use_multi_pack_reuse;
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int shared_repository;
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int shared_repository_initialized;
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/*
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* Does this repository have core.useReplaceRefs=true (on by
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* default)? This provides a repository-scoped version of this
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* config, though it could be disabled process-wide via some Git
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* builtins or the --no-replace-objects option. See
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* replace_refs_enabled() for more details.
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*/
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int read_replace_refs;
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struct fsmonitor_settings *fsmonitor; /* lazily loaded */
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int index_version;
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int index_skip_hash;
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enum untracked_cache_setting core_untracked_cache;
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int pack_use_sparse;
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int pack_use_path_walk;
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enum fetch_negotiation_setting fetch_negotiation_algorithm;
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int core_multi_pack_index;
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int warn_ambiguous_refs; /* lazily loaded via accessor */
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size_t delta_base_cache_limit;
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size_t packed_git_window_size;
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size_t packed_git_limit;
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unsigned long big_file_threshold;
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int max_allowed_tree_depth;
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char *hooks_path;
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};
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#define REPO_SETTINGS_INIT { \
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.shared_repository = -1, \
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.index_version = -1, \
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.core_untracked_cache = UNTRACKED_CACHE_KEEP, \
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.fetch_negotiation_algorithm = FETCH_NEGOTIATION_CONSECUTIVE, \
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.warn_ambiguous_refs = -1, \
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.delta_base_cache_limit = DEFAULT_DELTA_BASE_CACHE_LIMIT, \
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.packed_git_window_size = DEFAULT_PACKED_GIT_WINDOW_SIZE, \
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.packed_git_limit = DEFAULT_PACKED_GIT_LIMIT, \
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.max_allowed_tree_depth = DEFAULT_MAX_ALLOWED_TREE_DEPTH, \
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}
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void prepare_repo_settings(struct repository *r);
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void repo_settings_clear(struct repository *r);
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/* Read the value for "core.warnAmbiguousRefs". */
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int repo_settings_get_warn_ambiguous_refs(struct repository *repo);
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/* Read the value for "core.hooksPath". */
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const char *repo_settings_get_hooks_path(struct repository *repo);
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/* Read and set the value for "core.bigFileThreshold". */
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unsigned long repo_settings_get_big_file_threshold(struct repository *repo);
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void repo_settings_set_big_file_threshold(struct repository *repo, unsigned long value);
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/* Read, set or reset the value for "core.sharedRepository". */
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int repo_settings_get_shared_repository(struct repository *repo);
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void repo_settings_set_shared_repository(struct repository *repo, int value);
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void repo_settings_reset_shared_repository(struct repository *repo);
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#endif /* REPO_SETTINGS_H */
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