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[PATCH 3/9] pv4_tree_desc: introduce new struct for pack v4 tree walker

From
Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Date
Oct 9, 2013, 14:46 UTC
Message-ID
<1381329976-32082-4-git-send-email-pclouds@gmail.com>
In-Reply-To
<1381329976-32082-1-git-send-email-pclouds@gmail.com>

This struct is intended to be the successor of struct tree_desc. For now it only holds a buffer for converting pv4 tree to canonical format.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 packv4-parse.c | 73 ++++++++++++++++++++++++++++------------------------------
 packv4-parse.h |  9 ++++++++
 2 files changed, 44 insertions(+), 38 deletions(-)
diff --git a/packv4-parse.c b/packv4-parse.c
index 7b096cb..f9db364 100644
--- a/packv4-parse.c
+++ b/packv4-parse.c
@@ -344,9 +344,8 @@ void *pv4_get_commit(struct packed_git *p, struct pack_window **w_curs,
 	return dst;
 }
 
-static int copy_canonical_tree_entries(struct packed_git *p, off_t offset,
-				       unsigned int start, unsigned int count,
-				       unsigned char **dstp, unsigned long *sizep)
+static int copy_canonical_tree_entries(struct pv4_tree_desc *v4, off_t offset,
+				       unsigned int start, unsigned int count)
 {
 	void *data;
 	const unsigned char *from, *end;
@@ -354,7 +353,7 @@ static int copy_canonical_tree_entries(struct packed_git *p, off_t offset,
 	unsigned long size;
 	struct tree_desc desc;
 
-	data = unpack_entry(p, offset, &type, &size);
+	data = unpack_entry(v4->p, offset, &type, &size);
 	if (!data)
 		return -1;
 	if (type != OBJ_TREE) {
@@ -372,13 +371,11 @@ static int copy_canonical_tree_entries(struct packed_git *p, off_t offset,
 		update_tree_entry(&desc);
 	end = desc.buffer;
 
-	if (end - from > *sizep) {
+	if (end - from > strbuf_avail(&v4->buf)) {
 		free(data);
 		return -1;
 	}
-	memcpy(*dstp, from, end - from);
-	*dstp += end - from;
-	*sizep -= end - from;
+	strbuf_add(&v4->buf, from, end - from);
 	free(data);
 	return 0;
 }
@@ -417,7 +414,7 @@ static struct pv4_tree_cache *get_tree_offset_cache(struct packed_git *p, off_t
 	return c;
 }
 
-static int tree_entry_prefix(unsigned char *buf, unsigned long size,
+static int tree_entry_prefix(char *buf, unsigned long size,
 			     const unsigned char *path, int path_len,
 			     unsigned mode)
 {
@@ -443,35 +440,33 @@ static int tree_entry_prefix(unsigned char *buf, unsigned long size,
 	return len;
 }
 
-static int generate_tree_entry(struct packed_git *p,
+static int generate_tree_entry(struct pv4_tree_desc *desc,
 			       const unsigned char **bufp,
-			       unsigned char **dstp, unsigned long *sizep,
 			       int what)
 {
 	const unsigned char *path, *sha1;
+	char *buf = desc->buf.buf + desc->buf.len;
 	unsigned mode;
 	int len, pathlen;
 
-	path = get_pathref(p, what >> 1, &pathlen);
-	sha1 = get_sha1ref(p, bufp);
+	path = get_pathref(desc->p, what >> 1, &pathlen);
+	sha1 = get_sha1ref(desc->p, bufp);
 	if (!path || !sha1)
 		return -1;
 	mode = (path[0] << 8) | path[1];
-	len = tree_entry_prefix(*dstp, *sizep,
+	len = tree_entry_prefix(buf, strbuf_avail(&desc->buf),
 				path + 2, pathlen - 2, mode);
-	if (!len || len + 20 > *sizep)
+	if (!len || len + 20 > strbuf_avail(&desc->buf))
 		return -1;
-	hashcpy(*dstp + len, sha1);
-	len += 20;
-	*dstp += len;
-	*sizep -= len;
+	memcpy(buf + len, sha1, 20);
+	desc->buf.len += len + 20;
 	return 0;
 }
 
-static int decode_entries(struct packed_git *p, struct pack_window **w_curs,
-			  off_t obj_offset, unsigned int start, unsigned int count,
-			  unsigned char **dstp, unsigned long *sizep)
+static int decode_entries(struct pv4_tree_desc *desc, off_t obj_offset,
+			  unsigned int start, unsigned int count)
 {
+	struct packed_git *p = desc->p;
 	unsigned long avail;
 	const unsigned char *src, *scp;
 	unsigned int curpos;
@@ -490,7 +485,7 @@ static int decode_entries(struct packed_git *p, struct pack_window **w_curs,
 	} else {
 		unsigned int nb_entries;
 
-		src = use_pack(p, w_curs, obj_offset, &avail);
+		src = use_pack(p, &desc->w_curs, obj_offset, &avail);
 		scp = src;
 
 		/* we need to skip over the object header */
@@ -502,9 +497,8 @@ static int decode_entries(struct packed_git *p, struct pack_window **w_curs,
 		/* is this a canonical tree object? */
 		case OBJ_TREE:
 		case OBJ_REF_DELTA:
-			return copy_canonical_tree_entries(p, obj_offset,
-							   start, count,
-							   dstp, sizep);
+			return copy_canonical_tree_entries(desc, obj_offset,
+							   start, count);
 		/* let's still make sure this is actually a pv4 tree */
 		case OBJ_PV4_TREE:
 			break;
@@ -542,7 +536,7 @@ static int decode_entries(struct packed_git *p, struct pack_window **w_curs,
 		unsigned int what;
 
 		if (avail < 20) {
-			src = use_pack(p, w_curs, offset, &avail);
+			src = use_pack(p, &desc->w_curs, offset, &avail);
 			if (avail < 20)
 				return -1;
 		}
@@ -568,7 +562,7 @@ static int decode_entries(struct packed_git *p, struct pack_window **w_curs,
 			/*
 			 * This is an actual tree entry to recreate.
 			 */
-			if (generate_tree_entry(p, &scp, dstp, sizep, what))
+			if (generate_tree_entry(desc, &scp, what))
 				return -1;
 			count--;
 			curpos++;
@@ -638,9 +632,8 @@ static int decode_entries(struct packed_git *p, struct pack_window **w_curs,
 					start = 0;
 				}
 
-				ret = decode_entries(p, w_curs, copy_objoffset,
-						     copy_start, copy_count,
-						     dstp, sizep);
+				ret = decode_entries(desc, copy_objoffset,
+						     copy_start, copy_count);
 				if (ret)
 					return ret;
 
@@ -672,17 +665,21 @@ static int decode_entries(struct packed_git *p, struct pack_window **w_curs,
 void *pv4_get_tree(struct packed_git *p, struct pack_window **w_curs,
 		   off_t obj_offset, unsigned long size)
 {
-	unsigned char *dst, *dcp;
+	struct pv4_tree_desc desc;
 	int ret;
 
-	dst = xmallocz(size);
-	dcp = dst;
-	ret = decode_entries(p, w_curs, obj_offset, 0, 0, &dcp, &size);
-	if (ret < 0 || size != 0) {
-		free(dst);
+	memset(&desc, 0, sizeof(desc));
+	desc.p = p;
+	desc.w_curs = *w_curs;
+	strbuf_init(&desc.buf, size);
+
+	ret = decode_entries(&desc, obj_offset, 0, 0);
+	*w_curs = desc.w_curs;
+	if (ret < 0 || desc.buf.len != size) {
+		strbuf_release(&desc.buf);
 		return NULL;
 	}
-	return dst;
+	return strbuf_detach(&desc.buf, NULL);
 }
 
 unsigned long pv4_unpack_object_header_buffer(const unsigned char *base,
diff --git a/packv4-parse.h b/packv4-parse.h
index b437159..cad7a82 100644
--- a/packv4-parse.h
+++ b/packv4-parse.h
@@ -22,4 +22,13 @@ void *pv4_get_commit(struct packed_git *p, struct pack_window **w_curs,
 void *pv4_get_tree(struct packed_git *p, struct pack_window **w_curs,
 		   off_t obj_offset, unsigned long size);
 
+struct pv4_tree_desc {
+	/* v4 entry */
+	struct packed_git *p;
+	struct pack_window *w_curs;
+
+	/* full canonical tree */
+	struct strbuf buf;
+};
+
 #endif

-- 
1.8.2.83.gc99314b
Previous: Nguyễn Thái Ngọc DuyNext: Nguyễn Thái Ngọc Duy
Message 4 of 15 in “v4-aware tree walker API”
  1. 0/9 v4-aware tree walker APINguyễn Thái Ngọc Duy, Oct 9, 2013
  2. 1/9 sha1_file: provide real packed type in object_info_extendedNguyễn Thái Ngọc Duy, Oct 9, 2013
  3. 2/9 pack v4: move v2 tree entry generation code out of decode_entriesNguyễn Thái Ngọc Duy, Oct 9, 2013
  4. 3/9 pv4_tree_desc: introduce new struct for pack v4 tree walkerNguyễn Thái Ngọc Duy, Oct 9, 2013
  5. 4/9 pv4_tree_desc: use struct tree_desc from pv4_tree_descNguyễn Thái Ngọc Duy, Oct 9, 2013
  6. 5/9 pv4_tree_desc: allow decode_entries to return v4 trees, one at a timeNguyễn Thái Ngọc Duy, Oct 9, 2013
  7. 6/9 pv4_tree_desc: complete interfaceNguyễn Thái Ngọc Duy, Oct 9, 2013
  8. 7/9 pv4_tree_desc: don't bother looking for v4 trees if no v4 packs are presentNguyễn Thái Ngọc Duy, Oct 9, 2013
  9. 8/9 pv4_tree_desc: avoid lookup_object() when possibleNguyễn Thái Ngọc Duy, Oct 9, 2013
  10. 9/9 list-object.c: take "advantage" of new pv4_tree_desc interfaceNguyễn Thái Ngọc Duy, Oct 9, 2013
  11. Nicolas PitreOct 9, 2013
  12. Duy NguyenOct 11, 2013
  13. Duy NguyenOct 11, 2013
  14. Nicolas PitreOct 12, 2013
  15. Duy NguyenOct 12, 2013

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