X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=pack-objects.c;h=c0acc460bb9df0313e314eb2cf48363b2458082c;hb=245f1029d674b95d63b5faea2269f98d28b3adb2;hp=8da8aabf94c83c7da577f7ff420085ce0ba979e7;hpb=4b953cdc04fec8783e2c654a671005492fda9b01;p=git.git

diff --git a/pack-objects.c b/pack-objects.c
index 8da8aabf..c0acc460 100644
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -1,9 +1,13 @@
 #include "cache.h"
 #include "object.h"
+#include "blob.h"
+#include "commit.h"
+#include "tag.h"
+#include "tree.h"
 #include "delta.h"
 #include "pack.h"
 #include "csum-file.h"
-#include "diff.h"
+#include "tree-walk.h"
 #include <sys/time.h>
 #include <signal.h>
 
@@ -32,9 +36,6 @@ struct object_entry {
 				 * be used as the base objectto delta huge
 				 * objects against.
 				 */
-	int based_on_preferred;	/* current delta candidate is a preferred
-				 * one, or delta against a preferred one.
-				 */
 };
 
 /*
@@ -61,7 +62,7 @@ static int nr_objects = 0, nr_alloc = 0, nr_result = 0;
 static const char *base_name;
 static unsigned char pack_file_sha1[20];
 static int progress = 1;
-static volatile int progress_update = 0;
+static volatile sig_atomic_t progress_update = 0;
 
 /*
  * The object names in objects array are hashed with this hashtable,
@@ -99,7 +100,7 @@ static int reused_delta = 0;
 
 static int pack_revindex_ix(struct packed_git *p)
 {
-	unsigned int ui = (unsigned int) p;
+	unsigned long ui = (unsigned long)p;
 	int i;
 
 	ui = ui ^ (ui >> 16); /* defeat structure alignment */
@@ -452,7 +453,7 @@ static void rehash_objects(void)
 	if (object_ix_hashsz < 1024)
 		object_ix_hashsz = 1024;
 	object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
-	object_ix = memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
+	memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 	for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 		int ix = locate_object_entry_hash(oe->sha1);
 		if (0 <= ix)
@@ -462,9 +463,53 @@ static void rehash_objects(void)
 	}
 }
 
-static int add_object_entry(const unsigned char *sha1, const char *name, int exclude)
+struct name_path {
+	struct name_path *up;
+	const char *elem;
+	int len;
+};
+
+#define DIRBITS 12
+
+static unsigned name_hash(struct name_path *path, const char *name)
+{
+	struct name_path *p = path;
+	const char *n = name + strlen(name);
+	unsigned hash = 0, name_hash = 0, name_done = 0;
+
+	if (n != name && n[-1] == '\n')
+		n--;
+	while (name <= --n) {
+		unsigned char c = *n;
+		if (c == '/' && !name_done) {
+			name_hash = hash;
+			name_done = 1;
+			hash = 0;
+		}
+		hash = hash * 11 + c;
+	}
+	if (!name_done) {
+		name_hash = hash;
+		hash = 0;
+	}
+	for (p = path; p; p = p->up) {
+		hash = hash * 11 + '/';
+		n = p->elem + p->len;
+		while (p->elem <= --n) {
+			unsigned char c = *n;
+			hash = hash * 11 + c;
+		}
+	}
+	/*
+	 * Make sure "Makefile" and "t/Makefile" are hashed separately
+	 * but close enough.
+	 */
+	hash = (name_hash<<DIRBITS) | (hash & ((1U<<DIRBITS )-1));
+	return hash;
+}
+
+static int add_object_entry(const unsigned char *sha1, unsigned hash, int exclude)
 {
-	unsigned int hash = 0;
 	unsigned int idx = nr_objects;
 	struct object_entry *entry;
 	struct packed_git *p;
@@ -490,13 +535,6 @@ static int add_object_entry(const unsigned char *sha1, const char *name, int exc
 	if ((entry = locate_object_entry(sha1)) != NULL)
 		goto already_added;
 
-	while (*name) {
-		unsigned char c = *name++;
-		if (isspace(c))
-			continue;
-		hash = hash * 11 + c;
-	}
-
 	if (idx >= nr_alloc) {
 		unsigned int needed = (idx + 1024) * 3 / 2;
 		objects = xrealloc(objects, needed * sizeof(*entry));
@@ -534,49 +572,254 @@ static int add_object_entry(const unsigned char *sha1, const char *name, int exc
 	return status;
 }
 
-static void add_pbase_tree(struct tree_desc *tree)
+struct pbase_tree_cache {
+	unsigned char sha1[20];
+	int ref;
+	int temporary;
+	void *tree_data;
+	unsigned long tree_size;
+};
+
+static struct pbase_tree_cache *(pbase_tree_cache[256]);
+static int pbase_tree_cache_ix(const unsigned char *sha1)
+{
+	return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
+}
+static int pbase_tree_cache_ix_incr(int ix)
+{
+	return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
+}
+
+static struct pbase_tree {
+	struct pbase_tree *next;
+	/* This is a phony "cache" entry; we are not
+	 * going to evict it nor find it through _get()
+	 * mechanism -- this is for the toplevel node that
+	 * would almost always change with any commit.
+	 */
+	struct pbase_tree_cache pcache;
+} *pbase_tree;
+
+static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
+{
+	struct pbase_tree_cache *ent, *nent;
+	void *data;
+	unsigned long size;
+	char type[20];
+	int neigh;
+	int my_ix = pbase_tree_cache_ix(sha1);
+	int available_ix = -1;
+
+	/* pbase-tree-cache acts as a limited hashtable.
+	 * your object will be found at your index or within a few
+	 * slots after that slot if it is cached.
+	 */
+	for (neigh = 0; neigh < 8; neigh++) {
+		ent = pbase_tree_cache[my_ix];
+		if (ent && !memcmp(ent->sha1, sha1, 20)) {
+			ent->ref++;
+			return ent;
+		}
+		else if (((available_ix < 0) && (!ent || !ent->ref)) ||
+			 ((0 <= available_ix) &&
+			  (!ent && pbase_tree_cache[available_ix])))
+			available_ix = my_ix;
+		if (!ent)
+			break;
+		my_ix = pbase_tree_cache_ix_incr(my_ix);
+	}
+
+	/* Did not find one.  Either we got a bogus request or
+	 * we need to read and perhaps cache.
+	 */
+	data = read_sha1_file(sha1, type, &size);
+	if (!data)
+		return NULL;
+	if (strcmp(type, tree_type)) {
+		free(data);
+		return NULL;
+	}
+
+	/* We need to either cache or return a throwaway copy */
+
+	if (available_ix < 0)
+		ent = NULL;
+	else {
+		ent = pbase_tree_cache[available_ix];
+		my_ix = available_ix;
+	}
+
+	if (!ent) {
+		nent = xmalloc(sizeof(*nent));
+		nent->temporary = (available_ix < 0);
+	}
+	else {
+		/* evict and reuse */
+		free(ent->tree_data);
+		nent = ent;
+	}
+	memcpy(nent->sha1, sha1, 20);
+	nent->tree_data = data;
+	nent->tree_size = size;
+	nent->ref = 1;
+	if (!nent->temporary)
+		pbase_tree_cache[my_ix] = nent;
+	return nent;
+}
+
+static void pbase_tree_put(struct pbase_tree_cache *cache)
+{
+	if (!cache->temporary) {
+		cache->ref--;
+		return;
+	}
+	free(cache->tree_data);
+	free(cache);
+}
+
+static int name_cmp_len(const char *name)
+{
+	int i;
+	for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
+		;
+	return i;
+}
+
+static void add_pbase_object(struct tree_desc *tree,
+			     struct name_path *up,
+			     const char *name,
+			     int cmplen)
 {
 	while (tree->size) {
 		const unsigned char *sha1;
-		const char *name;
+		const char *entry_name;
+		int entry_len;
 		unsigned mode;
 		unsigned long size;
 		char type[20];
 
-		sha1 = tree_entry_extract(tree, &name, &mode);
+		sha1 = tree_entry_extract(tree, &entry_name, &mode);
 		update_tree_entry(tree);
-		if (!has_sha1_file(sha1))
-			continue;
-		if (sha1_object_info(sha1, type, &size))
+		entry_len = strlen(entry_name);
+		if (entry_len != cmplen ||
+		    memcmp(entry_name, name, cmplen) ||
+		    !has_sha1_file(sha1) ||
+		    sha1_object_info(sha1, type, &size))
 			continue;
+		if (name[cmplen] != '/') {
+			unsigned hash = name_hash(up, name);
+			add_object_entry(sha1, hash, 1);
+			return;
+		}
+		if (!strcmp(type, tree_type)) {
+			struct tree_desc sub;
+			struct name_path me;
+			struct pbase_tree_cache *tree;
+			const char *down = name+cmplen+1;
+			int downlen = name_cmp_len(down);
+
+			tree = pbase_tree_get(sha1);
+			if (!tree)
+				return;
+			sub.buf = tree->tree_data;
+			sub.size = tree->tree_size;
+
+			me.up = up;
+			me.elem = entry_name;
+			me.len = entry_len;
+			add_pbase_object(&sub, &me, down, downlen);
+			pbase_tree_put(tree);
+		}
+	}
+}
 
-		if (!add_object_entry(sha1, name, 1))
-			continue;
+static unsigned *done_pbase_paths;
+static int done_pbase_paths_num;
+static int done_pbase_paths_alloc;
+static int done_pbase_path_pos(unsigned hash)
+{
+	int lo = 0;
+	int hi = done_pbase_paths_num;
+	while (lo < hi) {
+		int mi = (hi + lo) / 2;
+		if (done_pbase_paths[mi] == hash)
+			return mi;
+		if (done_pbase_paths[mi] < hash)
+			hi = mi;
+		else
+			lo = mi + 1;
+	}
+	return -lo-1;
+}
 
-		if (!strcmp(type, "tree")) {
-			struct tree_desc sub;
-			void *elem;
-			elem = read_sha1_file(sha1, type, &sub.size);
-			sub.buf = elem;
-			if (sub.buf) {
-				add_pbase_tree(&sub);
-				free(elem);
-			}
+static int check_pbase_path(unsigned hash)
+{
+	int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
+	if (0 <= pos)
+		return 1;
+	pos = -pos - 1;
+	if (done_pbase_paths_alloc <= done_pbase_paths_num) {
+		done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
+		done_pbase_paths = xrealloc(done_pbase_paths,
+					    done_pbase_paths_alloc *
+					    sizeof(unsigned));
+	}
+	done_pbase_paths_num++;
+	if (pos < done_pbase_paths_num)
+		memmove(done_pbase_paths + pos + 1,
+			done_pbase_paths + pos,
+			(done_pbase_paths_num - pos - 1) * sizeof(unsigned));
+	done_pbase_paths[pos] = hash;
+	return 0;
+}
+
+static void add_preferred_base_object(char *name, unsigned hash)
+{
+	struct pbase_tree *it;
+	int cmplen = name_cmp_len(name);
+
+	if (check_pbase_path(hash))
+		return;
+
+	for (it = pbase_tree; it; it = it->next) {
+		if (cmplen == 0) {
+			hash = name_hash(NULL, "");
+			add_object_entry(it->pcache.sha1, hash, 1);
+		}
+		else {
+			struct tree_desc tree;
+			tree.buf = it->pcache.tree_data;
+			tree.size = it->pcache.tree_size;
+			add_pbase_object(&tree, NULL, name, cmplen);
 		}
 	}
 }
 
 static void add_preferred_base(unsigned char *sha1)
 {
-	struct tree_desc tree;
-	void *elem;
-	elem = read_object_with_reference(sha1, "tree", &tree.size, NULL);
-	tree.buf = elem;
-	if (!tree.buf)
+	struct pbase_tree *it;
+	void *data;
+	unsigned long size;
+	unsigned char tree_sha1[20];
+
+	data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
+	if (!data)
 		return;
-	if (add_object_entry(sha1, "", 1))
-		add_pbase_tree(&tree);
-	free(elem);
+
+	for (it = pbase_tree; it; it = it->next) {
+		if (!memcmp(it->pcache.sha1, tree_sha1, 20)) {
+			free(data);
+			return;
+		}
+	}
+
+	it = xcalloc(1, sizeof(*it));
+	it->next = pbase_tree;
+	pbase_tree = it;
+
+	memcpy(it->pcache.sha1, tree_sha1, 20);
+	it->pcache.tree_data = data;
+	it->pcache.tree_size = size;
 }
 
 static void check_object(struct object_entry *entry)
@@ -628,13 +871,13 @@ static void check_object(struct object_entry *entry)
 		die("unable to get type of object %s",
 		    sha1_to_hex(entry->sha1));
 
-	if (!strcmp(type, "commit")) {
+	if (!strcmp(type, commit_type)) {
 		entry->type = OBJ_COMMIT;
-	} else if (!strcmp(type, "tree")) {
+	} else if (!strcmp(type, tree_type)) {
 		entry->type = OBJ_TREE;
-	} else if (!strcmp(type, "blob")) {
+	} else if (!strcmp(type, blob_type)) {
 		entry->type = OBJ_BLOB;
-	} else if (!strcmp(type, "tag")) {
+	} else if (!strcmp(type, tag_type)) {
 		entry->type = OBJ_TAG;
 	} else
 		die("unable to pack object %s of type %s",
@@ -662,10 +905,23 @@ static void get_object_details(void)
 	prepare_pack_ix();
 	for (i = 0, entry = objects; i < nr_objects; i++, entry++)
 		check_object(entry);
-	for (i = 0, entry = objects; i < nr_objects; i++, entry++)
-		if (!entry->delta && entry->delta_child)
-			entry->delta_limit =
-				check_delta_limit(entry, 1);
+
+	if (nr_objects == nr_result) {
+		/*
+		 * Depth of objects that depend on the entry -- this
+		 * is subtracted from depth-max to break too deep
+		 * delta chain because of delta data reusing.
+		 * However, we loosen this restriction when we know we
+		 * are creating a thin pack -- it will have to be
+		 * expanded on the other end anyway, so do not
+		 * artificially cut the delta chain and let it go as
+		 * deep as it wants.
+		 */
+		for (i = 0, entry = objects; i < nr_objects; i++, entry++)
+			if (!entry->delta && entry->delta_child)
+				entry->delta_limit =
+					check_delta_limit(entry, 1);
+	}
 }
 
 typedef int (*entry_sort_t)(const struct object_entry *, const struct object_entry *);
@@ -696,7 +952,7 @@ static int sha1_sort(const struct object_entry *a, const struct object_entry *b)
 	return memcmp(a->sha1, b->sha1, 20);
 }
 
-static struct object_entry **create_final_object_list()
+static struct object_entry **create_final_object_list(void)
 {
 	struct object_entry **list;
 	int i, j;
@@ -752,8 +1008,6 @@ static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_de
 {
 	struct object_entry *cur_entry = cur->entry;
 	struct object_entry *old_entry = old->entry;
-	int old_preferred = (old_entry->preferred_base ||
-			     old_entry->based_on_preferred);
 	unsigned long size, oldsize, delta_size, sizediff;
 	long max_size;
 	void *delta_buf;
@@ -795,29 +1049,10 @@ static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_de
 	 * delete).
 	 */
 	max_size = size / 2 - 20;
-	if (cur_entry->delta) {
-		if (cur_entry->based_on_preferred) {
-			if (old_preferred)
-				max_size = cur_entry->delta_size-1;
-			else
-				/* trying with non-preferred one when we
-				 * already have a delta based on preferred
-				 * one is pointless.
-				 */
-				return -1;
-		}
-		else if (!old_preferred)
-			max_size = cur_entry->delta_size-1;
-		else
-			/* otherwise...  even if delta with a
-			 * preferred one produces a bigger result than
-			 * what we currently have, which is based on a
-			 * non-preferred one, it is OK.
-			 */
-			;
-	}
+	if (cur_entry->delta)
+		max_size = cur_entry->delta_size-1;
 	if (sizediff >= max_size)
-		return -1;
+		return 0;
 	delta_buf = diff_delta(old->data, oldsize,
 			       cur->data, size, &delta_size, max_size);
 	if (!delta_buf)
@@ -825,14 +1060,12 @@ static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_de
 	cur_entry->delta = old_entry;
 	cur_entry->delta_size = delta_size;
 	cur_entry->depth = old_entry->depth + 1;
-	cur_entry->based_on_preferred = old_preferred;
 	free(delta_buf);
 	return 0;
 }
 
 static void progress_interval(int signum)
 {
-	signal(SIGALRM, progress_interval);
 	progress_update = 1;
 }
 
@@ -894,6 +1127,15 @@ static void find_deltas(struct object_entry **list, int window, int depth)
 			if (try_delta(n, m, depth) < 0)
 				break;
 		}
+#if 0
+		/* if we made n a delta, and if n is already at max
+		 * depth, leaving it in the window is pointless.  we
+		 * should evict it first.
+		 * ... in theory only; somehow this makes things worse.
+		 */
+		if (entry->delta && depth <= entry->depth)
+			continue;
+#endif
 		idx++;
 		if (idx >= window)
 			idx = 0;
@@ -969,12 +1211,30 @@ static int reuse_cached_pack(unsigned char *sha1, int pack_to_stdout)
 	return 1;
 }
 
+static void setup_progress_signal(void)
+{
+	struct sigaction sa;
+	struct itimerval v;
+
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_handler = progress_interval;
+	sigemptyset(&sa.sa_mask);
+	sa.sa_flags = SA_RESTART;
+	sigaction(SIGALRM, &sa, NULL);
+
+	v.it_interval.tv_sec = 1;
+	v.it_interval.tv_usec = 0;
+	v.it_value = v.it_interval;
+	setitimer(ITIMER_REAL, &v, NULL);
+}
+
 int main(int argc, char **argv)
 {
 	SHA_CTX ctx;
-	char line[PATH_MAX + 20];
+	char line[40 + 1 + PATH_MAX + 2];
 	int window = 10, depth = 10, pack_to_stdout = 0;
 	struct object_entry **list;
+	int num_preferred_base = 0;
 	int i;
 
 	setup_git_directory();
@@ -1034,28 +1294,38 @@ int main(int argc, char **argv)
 	prepare_packed_git();
 
 	if (progress) {
-		struct itimerval v;
-		v.it_interval.tv_sec = 1;
-		v.it_interval.tv_usec = 0;
-		v.it_value = v.it_interval;
-		signal(SIGALRM, progress_interval);
-		setitimer(ITIMER_REAL, &v, NULL);
 		fprintf(stderr, "Generating pack...\n");
+		setup_progress_signal();
 	}
 
-	while (fgets(line, sizeof(line), stdin) != NULL) {
+	for (;;) {
 		unsigned char sha1[20];
+		unsigned hash;
+
+		if (!fgets(line, sizeof(line), stdin)) {
+			if (feof(stdin))
+				break;
+			if (!ferror(stdin))
+				die("fgets returned NULL, not EOF, not error!");
+			if (errno != EINTR)
+				die("fgets: %s", strerror(errno));
+			clearerr(stdin);
+			continue;
+		}
 
 		if (line[0] == '-') {
 			if (get_sha1_hex(line+1, sha1))
 				die("expected edge sha1, got garbage:\n %s",
 				    line+1);
-			add_preferred_base(sha1);
+			if (num_preferred_base++ < window)
+				add_preferred_base(sha1);
 			continue;
 		}
 		if (get_sha1_hex(line, sha1))
 			die("expected sha1, got garbage:\n %s", line);
-		add_object_entry(sha1, line+40, 0);
+		hash = name_hash(NULL, line+41);
+		add_preferred_base_object(line+41, hash);
+		add_object_entry(sha1, hash, 0);
 	}
 	if (progress)
 		fprintf(stderr, "Done counting %d objects.\n", nr_objects);