X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=pack-objects.c;h=b3e61520339231f6d9a43c545100f4d5f87e0aac;hb=0a8944dd48b97d258240af967dfdfcea4f203b85;hp=d9328a98d8f349b75fc5ab8302b66116317781ec;hpb=75c42d8cc3b42e4b82946848b8ba902b4bbcc38d;p=git.git

diff --git a/pack-objects.c b/pack-objects.c
index d9328a98..b3e61520 100644
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -1,78 +1,31 @@
 #include "cache.h"
 #include "object.h"
 #include "delta.h"
+#include "pack.h"
+#include "csum-file.h"
 
-static const char pack_usage[] = "git-pack-objects [--window=N] base-name < object-list";
-
-enum object_type {
-	OBJ_NONE,
-	OBJ_COMMIT,
-	OBJ_TREE,
-	OBJ_BLOB,
-	OBJ_DELTA	// NOTE! This is _not_ the same as a "delta" object in the filesystem
-};
+static const char pack_usage[] = "git-pack-objects [--local] [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list";
 
 struct object_entry {
 	unsigned char sha1[20];
 	unsigned long size;
 	unsigned long offset;
 	unsigned int depth;
-	unsigned int flags;
+	unsigned int hash;
 	enum object_type type;
 	unsigned long delta_size;
 	struct object_entry *delta;
 };
 
+static unsigned char object_list_sha1[20];
+static int non_empty = 0;
+static int local = 0;
+static int incremental = 0;
 static struct object_entry **sorted_by_sha, **sorted_by_type;
 static struct object_entry *objects = NULL;
 static int nr_objects = 0, nr_alloc = 0;
-static int delta_window = 10;
 static const char *base_name;
-
-struct myfile {
-	int fd;
-	unsigned long chars;
-	unsigned char buffer[8192];
-};
-
-static FILE *create_file(const char *suffix)
-{
-	static char filename[PATH_MAX];
-	unsigned len;
-
-	len = snprintf(filename, PATH_MAX, "%s.%s", base_name, suffix);
-	if (len >= PATH_MAX)
-		die("you wascally wabbit, you");
-	return fopen(filename, "w");
-}
-
-static unsigned long fwrite_compressed(void *in, unsigned long size, FILE *f)
-{
-	z_stream stream;
-	unsigned long maxsize;
-	void *out;
-
-	memset(&stream, 0, sizeof(stream));
-	deflateInit(&stream, Z_DEFAULT_COMPRESSION);
-	maxsize = deflateBound(&stream, size);
-	out = xmalloc(maxsize);
-
-	/* Compress it */
-	stream.next_in = in;
-	stream.avail_in = size;
-
-	stream.next_out = out;
-	stream.avail_out = maxsize;
-
-	while (deflate(&stream, Z_FINISH) == Z_OK)
-		/* nothing */;
-	deflateEnd(&stream);
-
-	size = stream.total_out;
-	fwrite(out, size, 1, f);
-	free(out);
-	return size;
-}
+static unsigned char pack_file_sha1[20];
 
 static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
 {
@@ -83,7 +36,8 @@ static void *delta_against(void *buf, unsigned long size, struct object_entry *e
 
 	if (!otherbuf)
 		die("unable to read %s", sha1_to_hex(entry->delta->sha1));
-        delta_buf = diff_delta(buf, size, otherbuf, othersize, &delta_size, ~0UL);
+        delta_buf = diff_delta(otherbuf, othersize,
+			       buf, size, &delta_size, 0);
         if (!delta_buf || delta_size != entry->delta_size)
         	die("delta size changed");
         free(buf);
@@ -91,13 +45,41 @@ static void *delta_against(void *buf, unsigned long size, struct object_entry *e
 	return delta_buf;
 }
 
-static unsigned long write_object(FILE *f, struct object_entry *entry)
+/*
+ * The per-object header is a pretty dense thing, which is
+ *  - first byte: low four bits are "size", then three bits of "type",
+ *    and the high bit is "size continues".
+ *  - each byte afterwards: low seven bits are size continuation,
+ *    with the high bit being "size continues"
+ */
+static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
+{
+	int n = 1;
+	unsigned char c;
+
+	if (type < OBJ_COMMIT || type > OBJ_DELTA)
+		die("bad type %d", type);
+
+	c = (type << 4) | (size & 15);
+	size >>= 4;
+	while (size) {
+		*hdr++ = c | 0x80;
+		c = size & 0x7f;
+		size >>= 7;
+		n++;
+	}
+	*hdr = c;
+	return n;
+}
+
+static unsigned long write_object(struct sha1file *f, struct object_entry *entry)
 {
 	unsigned long size;
 	char type[10];
 	void *buf = read_sha1_file(entry->sha1, type, &size);
-	char header[21];
+	unsigned char header[10];
 	unsigned hdrlen, datalen;
+	enum object_type obj_type;
 
 	if (!buf)
 		die("unable to read %s", sha1_to_hex(entry->sha1));
@@ -105,40 +87,65 @@ static unsigned long write_object(FILE *f, struct object_entry *entry)
 		die("object %s size inconsistency (%lu vs %lu)", sha1_to_hex(entry->sha1), size, entry->size);
 
 	/*
-	 * The object header is a byte of 'type' followed by four bytes of
-	 * length, except for deltas that has the 20 bytes of delta sha
-	 * instead.
+	 * The object header is a byte of 'type' followed by zero or
+	 * more bytes of length.  For deltas, the 20 bytes of delta sha1
+	 * follows that.
 	 */
-	header[0] = ".CTB"[entry->type];
-	datalen = htonl(size);
-	memcpy(header+1, &datalen, 4);
-	hdrlen = 5;
+	obj_type = entry->type;
 	if (entry->delta) {
-		header[0] = 'D';
-		memcpy(header+1, entry->delta, 20);
 		buf = delta_against(buf, size, entry);
 		size = entry->delta_size;
-		hdrlen = 21;
+		obj_type = OBJ_DELTA;
 	}
-	fwrite(header, hdrlen, 1, f);
-	datalen = fwrite_compressed(buf, size, f);
+	hdrlen = encode_header(obj_type, size, header);
+	sha1write(f, header, hdrlen);
+	if (entry->delta) {
+		sha1write(f, entry->delta, 20);
+		hdrlen += 20;
+	}
+	datalen = sha1write_compressed(f, buf, size);
 	free(buf);
 	return hdrlen + datalen;
 }
 
+static unsigned long write_one(struct sha1file *f,
+			       struct object_entry *e,
+			       unsigned long offset)
+{
+	if (e->offset)
+		/* offset starts from header size and cannot be zero
+		 * if it is written already.
+		 */
+		return offset;
+	e->offset = offset;
+	offset += write_object(f, e);
+	/* if we are delitified, write out its base object. */
+	if (e->delta)
+		offset = write_one(f, e->delta, offset);
+	return offset;
+}
+
 static void write_pack_file(void)
 {
 	int i;
-	FILE *f = create_file("pack");
-	unsigned long offset = 0;
+	struct sha1file *f;
+	unsigned long offset;
 	unsigned long mb;
+	struct pack_header hdr;
 
-	for (i = 0; i < nr_objects; i++) {
-		struct object_entry *entry = objects + i;
-		entry->offset = offset;
-		offset += write_object(f, entry);
-	}
-	fclose(f);
+	if (!base_name)
+		f = sha1fd(1, "<stdout>");
+	else
+		f = sha1create("%s-%s.%s", base_name, sha1_to_hex(object_list_sha1), "pack");
+	hdr.hdr_signature = htonl(PACK_SIGNATURE);
+	hdr.hdr_version = htonl(PACK_VERSION);
+	hdr.hdr_entries = htonl(nr_objects);
+	sha1write(f, &hdr, sizeof(hdr));
+	offset = sizeof(hdr);
+	for (i = 0; i < nr_objects; i++)
+		offset = write_one(f, objects + i, offset);
+
+	sha1close(f, pack_file_sha1, 1);
 	mb = offset >> 20;
 	offset &= 0xfffff;
 }
@@ -146,7 +153,7 @@ static void write_pack_file(void)
 static void write_index_file(void)
 {
 	int i;
-	FILE *f = create_file("idx");
+	struct sha1file *f = sha1create("%s-%s.%s", base_name, sha1_to_hex(object_list_sha1), "idx");
 	struct object_entry **list = sorted_by_sha;
 	struct object_entry **last = list + nr_objects;
 	unsigned int array[256];
@@ -154,7 +161,7 @@ static void write_index_file(void)
 	/*
 	 * Write the first-level table (the list is sorted,
 	 * but we use a 256-entry lookup to be able to avoid
-	 * having to do eight extra binary search iterations)
+	 * having to do eight extra binary search iterations).
 	 */
 	for (i = 0; i < 256; i++) {
 		struct object_entry **next = list;
@@ -167,7 +174,7 @@ static void write_index_file(void)
 		array[i] = htonl(next - sorted_by_sha);
 		list = next;
 	}
-	fwrite(array, 256, sizeof(int), f);
+	sha1write(f, array, 256 * sizeof(int));
 
 	/*
 	 * Write the actual SHA1 entries..
@@ -176,17 +183,33 @@ static void write_index_file(void)
 	for (i = 0; i < nr_objects; i++) {
 		struct object_entry *entry = *list++;
 		unsigned int offset = htonl(entry->offset);
-		fwrite(&offset, 4, 1, f);
-		fwrite(entry->sha1, 20, 1, f);
+		sha1write(f, &offset, 4);
+		sha1write(f, entry->sha1, 20);
 	}
-	fclose(f);
+	sha1write(f, pack_file_sha1, 20);
+	sha1close(f, NULL, 1);
 }
 
-static void add_object_entry(unsigned char *sha1)
+static int add_object_entry(unsigned char *sha1, unsigned int hash)
 {
 	unsigned int idx = nr_objects;
 	struct object_entry *entry;
 
+	if (incremental || local) {
+		struct packed_git *p;
+
+		for (p = packed_git; p; p = p->next) {
+			struct pack_entry e;
+
+			if (find_pack_entry_one(sha1, &e, p)) {
+				if (incremental)
+					return 0;
+				if (local && !p->pack_local)
+					return 0;
+			}
+		}
+	}
+
 	if (idx >= nr_alloc) {
 		unsigned int needed = (idx + 1024) * 3 / 2;
 		objects = xrealloc(objects, needed * sizeof(*entry));
@@ -195,33 +218,31 @@ static void add_object_entry(unsigned char *sha1)
 	entry = objects + idx;
 	memset(entry, 0, sizeof(*entry));
 	memcpy(entry->sha1, sha1, 20);
+	entry->hash = hash;
 	nr_objects = idx+1;
+	return 1;
 }
 
 static void check_object(struct object_entry *entry)
 {
-	char buffer[128];
-	char type[10];
-	unsigned long mapsize;
-	z_stream stream;
-	void *map;
-
-	map = map_sha1_file(entry->sha1, &mapsize);
-	if (!map)
-		die("unable to map %s", sha1_to_hex(entry->sha1));
-	if (unpack_sha1_header(&stream, map, mapsize, buffer, sizeof(buffer)) < 0)
-		die("unable to unpack %s header", sha1_to_hex(entry->sha1));
-	munmap(map, mapsize);
-	if (parse_sha1_header(buffer, type, &entry->size) < 0)
-		die("unable to parse %s header", sha1_to_hex(entry->sha1));
-	if (!strcmp(type, "commit")) {
-		entry->type = OBJ_COMMIT;
-	} else if (!strcmp(type, "tree")) {
-		entry->type = OBJ_TREE;
-	} else if (!strcmp(type, "blob")) {
-		entry->type = OBJ_BLOB;
-	} else
-		die("unable to pack object %s of type %s", sha1_to_hex(entry->sha1), type);
+	char type[20];
+
+	if (!sha1_object_info(entry->sha1, type, &entry->size)) {
+		if (!strcmp(type, "commit")) {
+			entry->type = OBJ_COMMIT;
+		} else if (!strcmp(type, "tree")) {
+			entry->type = OBJ_TREE;
+		} else if (!strcmp(type, "blob")) {
+			entry->type = OBJ_BLOB;
+		} else if (!strcmp(type, "tag")) {
+			entry->type = OBJ_TAG;
+		} else
+			die("unable to pack object %s of type %s",
+			    sha1_to_hex(entry->sha1), type);
+	}
+	else
+		die("unable to get type of object %s",
+		    sha1_to_hex(entry->sha1));
 }
 
 static void get_object_details(void)
@@ -267,6 +288,10 @@ static int type_size_sort(const struct object_entry *a, const struct object_entr
 		return -1;
 	if (a->type > b->type)
 		return 1;
+	if (a->hash < b->hash)
+		return -1;
+	if (a->hash > b->hash)
+		return 1;
 	if (a->size < b->size)
 		return -1;
 	if (a->size > b->size)
@@ -280,18 +305,18 @@ struct unpacked {
 };
 
 /*
- * We search for deltas in a list sorted by type and by size, and
- * walk the "old" chain backwards in the list, so if the type
- * has changed or the size difference is too big, there's no point
- * in even continuing the walk, since the other old objects are
- * going to be even smaller or of a different type. So return -1
- * once we determine that there's no point even trying.
+ * We search for deltas _backwards_ in a list sorted by type and
+ * by size, so that we see progressively smaller and smaller files.
+ * That's because we prefer deltas to be from the bigger file
+ * to the smaller - deletes are potentially cheaper, but perhaps
+ * more importantly, the bigger file is likely the more recent
+ * one.
  */
-static int try_delta(struct unpacked *cur, struct unpacked *old)
+static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_depth)
 {
 	struct object_entry *cur_entry = cur->entry;
 	struct object_entry *old_entry = old->entry;
-	unsigned long size, oldsize, delta_size;
+	unsigned long size, oldsize, delta_size, sizediff;
 	long max_size;
 	void *delta_buf;
 
@@ -299,13 +324,15 @@ static int try_delta(struct unpacked *cur, struct unpacked *old)
 	if (cur_entry->type != old_entry->type)
 		return -1;
 
-	/* Size is guaranteed to be larger than or equal to oldsize */
 	size = cur_entry->size;
 	if (size < 50)
 		return -1;
 	oldsize = old_entry->size;
-	if (size - oldsize > oldsize / 4)
+	sizediff = oldsize > size ? oldsize - size : size - oldsize;
+	if (sizediff > size / 8)
 		return -1;
+	if (old_entry->depth >= max_depth)
+		return 0;
 
 	/*
 	 * NOTE!
@@ -317,24 +344,29 @@ static int try_delta(struct unpacked *cur, struct unpacked *old)
 	max_size = size / 2 - 20;
 	if (cur_entry->delta)
 		max_size = cur_entry->delta_size-1;
-	delta_buf = diff_delta(cur->data, size, old->data, oldsize, &delta_size, max_size);
+	if (sizediff >= max_size)
+		return -1;
+	delta_buf = diff_delta(old->data, oldsize,
+			       cur->data, size, &delta_size, max_size);
 	if (!delta_buf)
 		return 0;
 	cur_entry->delta = old_entry;
 	cur_entry->delta_size = delta_size;
+	cur_entry->depth = old_entry->depth + 1;
 	free(delta_buf);
 	return 0;
 }
 
-static void find_deltas(struct object_entry **list, int window)
+static void find_deltas(struct object_entry **list, int window, int depth)
 {
-	unsigned int i;
+	int i, idx;
 	unsigned int array_size = window * sizeof(struct unpacked);
 	struct unpacked *array = xmalloc(array_size);
 
 	memset(array, 0, array_size);
-	for (i = 0; i < nr_objects; i++) {
-		unsigned int idx = i % window;
+	i = nr_objects;
+	idx = 0;
+	while (--i >= 0) {
 		struct object_entry *entry = list[i];
 		struct unpacked *n = array + idx;
 		unsigned long size;
@@ -355,28 +387,61 @@ static void find_deltas(struct object_entry **list, int window)
 			m = array + other_idx;
 			if (!m->entry)
 				break;
-			if (try_delta(n, m) < 0)
+			if (try_delta(n, m, depth) < 0)
 				break;
 		}
+		idx++;
+		if (idx >= window)
+			idx = 0;
 	}
+
+	for (i = 0; i < window; ++i)
+		free(array[i].data);
+	free(array);
 }
 
 int main(int argc, char **argv)
 {
-	char line[128];
+	SHA_CTX ctx;
+	char line[PATH_MAX + 20];
+	int window = 10, depth = 10, pack_to_stdout = 0;
+	struct object_entry **list;
 	int i;
 
 	for (i = 1; i < argc; i++) {
 		const char *arg = argv[i];
 
 		if (*arg == '-') {
+			if (!strcmp("--non-empty", arg)) {
+				non_empty = 1;
+				continue;
+			}
+			if (!strcmp("--local", arg)) {
+				local = 1;
+				continue;
+			}
+			if (!strcmp("--incremental", arg)) {
+				incremental = 1;
+				continue;
+			}
 			if (!strncmp("--window=", arg, 9)) {
 				char *end;
-				delta_window = strtoul(arg+9, &end, 0);
+				window = strtoul(arg+9, &end, 0);
 				if (!arg[9] || *end)
 					usage(pack_usage);
 				continue;
 			}
+			if (!strncmp("--depth=", arg, 8)) {
+				char *end;
+				depth = strtoul(arg+8, &end, 0);
+				if (!arg[8] || *end)
+					usage(pack_usage);
+				continue;
+			}
+			if (!strcmp("--stdout", arg)) {
+				pack_to_stdout = 1;
+				continue;
+			}
 			usage(pack_usage);
 		}
 		if (base_name)
@@ -384,25 +449,50 @@ int main(int argc, char **argv)
 		base_name = arg;
 	}
 
-	if (!base_name)
+	if (pack_to_stdout != !base_name)
 		usage(pack_usage);
 
+	prepare_packed_git();
 	while (fgets(line, sizeof(line), stdin) != NULL) {
+		unsigned int hash;
+		char *p;
 		unsigned char sha1[20];
+
 		if (get_sha1_hex(line, sha1))
 			die("expected sha1, got garbage");
-		add_object_entry(sha1);
+		hash = 0;
+		p = line+40;
+		while (*p) {
+			unsigned char c = *p++;
+			if (isspace(c))
+				continue;
+			hash = hash * 11 + c;
+		}
+		add_object_entry(sha1, hash);
 	}
+	if (non_empty && !nr_objects)
+		return 0;
 	get_object_details();
 
-	printf("Packing %d objects\n", nr_objects);
+	fprintf(stderr, "Packing %d objects\n", nr_objects);
 
 	sorted_by_sha = create_sorted_list(sha1_sort);
+	SHA1_Init(&ctx);
+	list = sorted_by_sha;
+	for (i = 0; i < nr_objects; i++) {
+		struct object_entry *entry = *list++;
+		SHA1_Update(&ctx, entry->sha1, 20);
+	}
+	SHA1_Final(object_list_sha1, &ctx);
+
 	sorted_by_type = create_sorted_list(type_size_sort);
-	if (delta_window)
-		find_deltas(sorted_by_type, delta_window);
+	if (window && depth)
+		find_deltas(sorted_by_type, window+1, depth);
 
 	write_pack_file();
-	write_index_file();
+	if (!pack_to_stdout) {
+		write_index_file();
+		puts(sha1_to_hex(object_list_sha1));
+	}
 	return 0;
 }