Adding upstream version 1:2.39.2.upstream/1%2.39.2upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 307 insertions, 0 deletions

diff --git a/pack-objects.h b/pack-objects.h
new file mode 100644
index 0000000..5794766
--- /dev/null
+++ b/pack-objects.h
@@ -0,0 +1,307 @@
+#ifndef PACK_OBJECTS_H
+#define PACK_OBJECTS_H
+
+#include "object-store.h"
+#include "thread-utils.h"
+#include "pack.h"
+
+struct repository;
+
+#define DEFAULT_DELTA_CACHE_SIZE (256 * 1024 * 1024)
+
+#define OE_DFS_STATE_BITS	2
+#define OE_DEPTH_BITS		12
+#define OE_IN_PACK_BITS		10
+#define OE_Z_DELTA_BITS		20
+/*
+ * Note that oe_set_size() becomes expensive when the given size is
+ * above this limit. Don't lower it too much.
+ */
+#define OE_SIZE_BITS		31
+#define OE_DELTA_SIZE_BITS	23
+
+/*
+ * State flags for depth-first search used for analyzing delta cycles.
+ *
+ * The depth is measured in delta-links to the base (so if A is a delta
+ * against B, then A has a depth of 1, and B a depth of 0).
+ */
+enum dfs_state {
+	DFS_NONE = 0,
+	DFS_ACTIVE,
+	DFS_DONE,
+	DFS_NUM_STATES
+};
+
+/*
+ * The size of struct nearly determines pack-objects's memory
+ * consumption. This struct is packed tight for that reason. When you
+ * add or reorder something in this struct, think a bit about this.
+ *
+ * basic object info
+ * -----------------
+ * idx.oid is filled up before delta searching starts. idx.crc32 is
+ * only valid after the object is written out and will be used for
+ * generating the index. idx.offset will be both gradually set and
+ * used in writing phase (base objects get offset first, then deltas
+ * refer to them)
+ *
+ * "size" is the uncompressed object size. Compressed size of the raw
+ * data for an object in a pack is not stored anywhere but is computed
+ * and made available when reverse .idx is made. Note that when a
+ * delta is reused, "size" is the uncompressed _delta_ size, not the
+ * canonical one after the delta has been applied.
+ *
+ * "hash" contains a path name hash which is used for sorting the
+ * delta list and also during delta searching. Once prepare_pack()
+ * returns it's no longer needed.
+ *
+ * source pack info
+ * ----------------
+ * The (in_pack, in_pack_offset) tuple contains the location of the
+ * object in the source pack. in_pack_header_size allows quickly
+ * skipping the header and going straight to the zlib stream.
+ *
+ * "type" and "in_pack_type" both describe object type. in_pack_type
+ * may contain a delta type, while type is always the canonical type.
+ *
+ * deltas
+ * ------
+ * Delta links (delta, delta_child and delta_sibling) are created to
+ * reflect that delta graph from the source pack then updated or added
+ * during delta searching phase when we find better deltas.
+ *
+ * delta_child and delta_sibling are last needed in
+ * compute_write_order(). "delta" and "delta_size" must remain valid
+ * at object writing phase in case the delta is not cached.
+ *
+ * If a delta is cached in memory and is compressed, delta_data points
+ * to the data and z_delta_size contains the compressed size. If it's
+ * uncompressed [1], z_delta_size must be zero. delta_size is always
+ * the uncompressed size and must be valid even if the delta is not
+ * cached.
+ *
+ * [1] during try_delta phase we don't bother with compressing because
+ * the delta could be quickly replaced with a better one.
+ */
+struct object_entry {
+	struct pack_idx_entry idx;
+	void *delta_data;	/* cached delta (uncompressed) */
+	off_t in_pack_offset;
+	uint32_t hash;			/* name hint hash */
+	unsigned size_:OE_SIZE_BITS;
+	unsigned size_valid:1;
+	uint32_t delta_idx;	/* delta base object */
+	uint32_t delta_child_idx; /* deltified objects who bases me */
+	uint32_t delta_sibling_idx; /* other deltified objects who
+				     * uses the same base as me
+				     */
+	unsigned delta_size_:OE_DELTA_SIZE_BITS; /* delta data size (uncompressed) */
+	unsigned delta_size_valid:1;
+	unsigned char in_pack_header_size;
+	unsigned in_pack_idx:OE_IN_PACK_BITS;	/* already in pack */
+	unsigned z_delta_size:OE_Z_DELTA_BITS;
+	unsigned type_valid:1;
+	unsigned no_try_delta:1;
+	unsigned type_:TYPE_BITS;
+	unsigned in_pack_type:TYPE_BITS; /* could be delta */
+
+	unsigned preferred_base:1; /*
+				    * we do not pack this, but is available
+				    * to be used as the base object to delta
+				    * objects against.
+				    */
+	unsigned tagged:1; /* near the very tip of refs */
+	unsigned filled:1; /* assigned write-order */
+	unsigned dfs_state:OE_DFS_STATE_BITS;
+	unsigned depth:OE_DEPTH_BITS;
+	unsigned ext_base:1; /* delta_idx points outside packlist */
+};
+
+struct packing_data {
+	struct repository *repo;
+	struct object_entry *objects;
+	uint32_t nr_objects, nr_alloc;
+
+	int32_t *index;
+	uint32_t index_size;
+
+	unsigned int *in_pack_pos;
+	unsigned long *delta_size;
+
+	/*
+	 * Only one of these can be non-NULL and they have different
+	 * sizes. if in_pack_by_idx is allocated, oe_in_pack() returns
+	 * the pack of an object using in_pack_idx field. If not,
+	 * in_pack[] array is used the same way as in_pack_pos[]
+	 */
+	struct packed_git **in_pack_by_idx;
+	struct packed_git **in_pack;
+
+	/*
+	 * During packing with multiple threads, protect the in-core
+	 * object database from concurrent accesses.
+	 */
+	pthread_mutex_t odb_lock;
+
+	/*
+	 * This list contains entries for bases which we know the other side
+	 * has (e.g., via reachability bitmaps), but which aren't in our
+	 * "objects" list.
+	 */
+	struct object_entry *ext_bases;
+	uint32_t nr_ext, alloc_ext;
+
+	uintmax_t oe_size_limit;
+	uintmax_t oe_delta_size_limit;
+
+	/* delta islands */
+	unsigned int *tree_depth;
+	unsigned char *layer;
+
+	/*
+	 * Used when writing cruft packs.
+	 *
+	 * Object mtimes are stored in pack order when writing, but
+	 * written out in lexicographic (index) order.
+	 */
+	uint32_t *cruft_mtime;
+};
+
+void prepare_packing_data(struct repository *r, struct packing_data *pdata);
+
+/* Protect access to object database */
+static inline void packing_data_lock(struct packing_data *pdata)
+{
+	pthread_mutex_lock(&pdata->odb_lock);
+}
+static inline void packing_data_unlock(struct packing_data *pdata)
+{
+	pthread_mutex_unlock(&pdata->odb_lock);
+}
+
+struct object_entry *packlist_alloc(struct packing_data *pdata,
+				    const struct object_id *oid);
+
+struct object_entry *packlist_find(struct packing_data *pdata,
+				   const struct object_id *oid);
+
+static inline uint32_t pack_name_hash(const char *name)
+{
+	uint32_t c, hash = 0;
+
+	if (!name)
+		return 0;
+
+	/*
+	 * This effectively just creates a sortable number from the
+	 * last sixteen non-whitespace characters. Last characters
+	 * count "most", so things that end in ".c" sort together.
+	 */
+	while ((c = *name++) != 0) {
+		if (isspace(c))
+			continue;
+		hash = (hash >> 2) + (c << 24);
+	}
+	return hash;
+}
+
+static inline enum object_type oe_type(const struct object_entry *e)
+{
+	return e->type_valid ? e->type_ : OBJ_BAD;
+}
+
+static inline void oe_set_type(struct object_entry *e,
+			       enum object_type type)
+{
+	if (type >= OBJ_ANY)
+		BUG("OBJ_ANY cannot be set in pack-objects code");
+
+	e->type_valid = type >= OBJ_NONE;
+	e->type_ = (unsigned)type;
+}
+
+static inline unsigned int oe_in_pack_pos(const struct packing_data *pack,
+					  const struct object_entry *e)
+{
+	return pack->in_pack_pos[e - pack->objects];
+}
+
+static inline void oe_set_in_pack_pos(const struct packing_data *pack,
+				      const struct object_entry *e,
+				      unsigned int pos)
+{
+	pack->in_pack_pos[e - pack->objects] = pos;
+}
+
+static inline struct packed_git *oe_in_pack(const struct packing_data *pack,
+					    const struct object_entry *e)
+{
+	if (pack->in_pack_by_idx)
+		return pack->in_pack_by_idx[e->in_pack_idx];
+	else
+		return pack->in_pack[e - pack->objects];
+}
+
+void oe_map_new_pack(struct packing_data *pack);
+
+static inline void oe_set_in_pack(struct packing_data *pack,
+				  struct object_entry *e,
+				  struct packed_git *p)
+{
+	if (pack->in_pack_by_idx) {
+		if (p->index) {
+			e->in_pack_idx = p->index;
+			return;
+		}
+		/*
+		 * We're accessing packs by index, but this pack doesn't have
+		 * an index (e.g., because it was added since we created the
+		 * in_pack_by_idx array). Bail to oe_map_new_pack(), which
+		 * will convert us to using the full in_pack array, and then
+		 * fall through to our in_pack handling.
+		 */
+		oe_map_new_pack(pack);
+	}
+	pack->in_pack[e - pack->objects] = p;
+}
+
+void oe_set_delta_ext(struct packing_data *pack,
+		      struct object_entry *e,
+		      const struct object_id *oid);
+
+static inline unsigned int oe_tree_depth(struct packing_data *pack,
+					 struct object_entry *e)
+{
+	if (!pack->tree_depth)
+		return 0;
+	return pack->tree_depth[e - pack->objects];
+}
+
+static inline void oe_set_layer(struct packing_data *pack,
+				struct object_entry *e,
+				unsigned char layer)
+{
+	if (!pack->layer)
+		CALLOC_ARRAY(pack->layer, pack->nr_alloc);
+	pack->layer[e - pack->objects] = layer;
+}
+
+static inline uint32_t oe_cruft_mtime(struct packing_data *pack,
+				      struct object_entry *e)
+{
+	if (!pack->cruft_mtime)
+		return 0;
+	return pack->cruft_mtime[e - pack->objects];
+}
+
+static inline void oe_set_cruft_mtime(struct packing_data *pack,
+				      struct object_entry *e,
+				      uint32_t mtime)
+{
+	if (!pack->cruft_mtime)
+		CALLOC_ARRAY(pack->cruft_mtime, pack->nr_alloc);
+	pack->cruft_mtime[e - pack->objects] = mtime;
+}
+
+#endif