Simplify "write_sha1_file()" interfaces

The write function now adds the header to the file by itself, so there
is no reason to duplicate it among all the users any more.

Author: Linus Torvalds

cache.h

@@ -121,7 +121,7 @@ extern int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int
 extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
 extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
 extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
-extern int write_sha1_file(char *buf, unsigned len, unsigned char *return_sha1);
+extern int write_sha1_file(char *buf, unsigned len, const char *type, unsigned char *return_sha1);
 
 extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size, const char *type);
 

commit-tree.c

@@ -12,19 +12,14 @@
 #include <time.h>
 
 #define BLOCKING (1ul << 14)
-#define ORIG_OFFSET (40)
 
 /*
- * Leave space at the beginning to insert the tag
- * once we know how big things are.
- *
  * FIXME! Share the code with "write-tree.c"
  */
 static void init_buffer(char **bufp, unsigned int *sizep)
 {
 	char *buf = malloc(BLOCKING);
-	memset(buf, 0, ORIG_OFFSET);
-	*sizep = ORIG_OFFSET;
+	*sizep = 0;
 	*bufp = buf;
 }
 
@@ -52,34 +47,6 @@ static void add_buffer(char **bufp, unsigned int *sizep, const char *fmt, ...)
 	memcpy(buf + size, one_line, len);
 }
 
-static int prepend_integer(char *buffer, unsigned val, int i)
-{
-	buffer[--i] = '\0';
-	do {
-		buffer[--i] = '0' + (val % 10);
-		val /= 10;
-	} while (val);
-	return i;
-}
-
-static void finish_buffer(char *tag, char **bufp, unsigned int *sizep)
-{
-	int taglen;
-	int offset;
-	char *buf = *bufp;
-	unsigned int size = *sizep;
-
-	offset = prepend_integer(buf, size - ORIG_OFFSET, ORIG_OFFSET);
-	taglen = strlen(tag);
-	offset -= taglen;
-	buf += offset;
-	size -= offset;
-	memcpy(buf, tag, taglen);
-
-	*bufp = buf;
-	*sizep = size;
-}
-
 static void remove_special(char *p)
 {
 	char c;
@@ -355,9 +322,7 @@ int main(int argc, char **argv)
 	while (fgets(comment, sizeof(comment), stdin) != NULL)
 		add_buffer(&buffer, &size, "%s", comment);
 
-	finish_buffer("commit ", &buffer, &size);
-
-	write_sha1_file(buffer, size, commit_sha1);
+	write_sha1_file(buffer, size, "commit", commit_sha1);
 	printf("%s\n", sha1_to_hex(commit_sha1));
 	return 0;
 }

convert-cache.c

@@ -66,25 +66,11 @@ static void convert_ascii_sha1(void *buffer)
 	memcpy(buffer, sha1_to_hex(entry->new_sha1), 40);
 }
 
-#define ORIG_OFFSET (40)
-
-static int prepend_integer(char *buffer, unsigned val, int i)
-{
-	buffer[--i] = '\0';
-	do {
-		buffer[--i] = '0' + (val % 10);
-		val /= 10;
-	} while (val);
-	return i;
-}
-
-
 static int write_subdirectory(void *buffer, unsigned long size, const char *base, int baselen, unsigned char *result_sha1)
 {
-	char *new = malloc(size + ORIG_OFFSET);
-	unsigned long newlen = ORIG_OFFSET;
+	char *new = malloc(size);
+	unsigned long newlen = 0;
 	unsigned long used;
-	int i;
 
 	used = 0;
 	while (size) {
@@ -126,11 +112,7 @@ static int write_subdirectory(void *buffer, unsigned long size, const char *base
 		buffer += len;
 	}
 
-	i = prepend_integer(new, newlen - ORIG_OFFSET, ORIG_OFFSET);
-	i -= 5;
-	memcpy(new + i, "tree ", 5);
-
-	write_sha1_file(new + i, newlen - i, result_sha1);
+	write_sha1_file(new, newlen, "tree", result_sha1);
 	free(new);
 	return used;
 }
@@ -244,9 +226,8 @@ static int convert_date_line(char *dst, void **buf, unsigned long *sp)
 
 static void convert_date(void *buffer, unsigned long size, unsigned char *result_sha1)
 {
-	char *new = malloc(size + ORIG_OFFSET + 100);
-	unsigned long newlen = ORIG_OFFSET;
-	int i;
+	char *new = malloc(size + 100);
+	unsigned long newlen = 0;
 
 	// "tree <sha1>\n"
 	memcpy(new + newlen, buffer, 46);
@@ -271,11 +252,7 @@ static void convert_date(void *buffer, unsigned long size, unsigned char *result
 	memcpy(new + newlen, buffer, size);
 	newlen += size;
 
-	i = prepend_integer(new, newlen - ORIG_OFFSET, ORIG_OFFSET);
-	i -= 7;
-	memcpy(new + i, "commit ", 7);
-
-	write_sha1_file(new + i, newlen - i, result_sha1);
+	write_sha1_file(new, newlen, "commit", result_sha1);
 	free(new);	
 }
 
@@ -298,24 +275,23 @@ static struct entry * convert_entry(unsigned char *sha1)
 	struct entry *entry = lookup_entry(sha1);
 	char type[20];
 	void *buffer, *data;
-	unsigned long size, offset;
+	unsigned long size;
 
 	if (entry->converted)
 		return entry;
 	data = read_sha1_file(sha1, type, &size);
 	if (!data)
 		die("unable to read object %s", sha1_to_hex(sha1));
 
-	buffer = malloc(size + 100);
-	offset = sprintf(buffer, "%s %lu", type, size)+1;
-	memcpy(buffer + offset, data, size);
+	buffer = malloc(size);
+	memcpy(buffer, data, size);
 
 	if (!strcmp(type, "blob")) {
-		write_sha1_file(buffer, size + offset, entry->new_sha1);
+		write_sha1_file(buffer, size, "blob", entry->new_sha1);
 	} else if (!strcmp(type, "tree"))
-		convert_tree(buffer + offset, size, entry->new_sha1);
+		convert_tree(buffer, size, entry->new_sha1);
 	else if (!strcmp(type, "commit"))
-		convert_commit(buffer + offset, size, entry->new_sha1);
+		convert_commit(buffer, size, entry->new_sha1);
 	else
 		die("unknown object type '%s' in %s", type, sha1_to_hex(sha1));
 	entry->converted = 1;

sha1_file.c

@@ -155,8 +155,8 @@ void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned l
 
 	inflateInit(&stream);
 	ret = inflate(&stream, 0);
-       if (ret < Z_OK)
-               return NULL;
+	if (ret < Z_OK)
+		return NULL;
 	if (sscanf(buffer, "%10s %lu", type, size) != 2)
 		return NULL;
 
@@ -231,18 +231,23 @@ void *read_tree_with_tree_or_commit_sha1(const unsigned char *sha1,
 	return buffer;
 }
 
-int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
+int write_sha1_file(char *buf, unsigned len, const char *type, unsigned char *returnsha1)
 {
 	int size;
 	char *compressed;
 	z_stream stream;
 	unsigned char sha1[20];
 	SHA_CTX c;
 	char *filename;
-	int fd;
+	char hdr[50];
+	int fd, hdrlen;
+
+	/* Generate the header */
+	hdrlen = sprintf(hdr, "%s %d", type, len)+1;
 
 	/* Sha1.. */
 	SHA1_Init(&c);
+	SHA1_Update(&c, hdr, hdrlen);
 	SHA1_Update(&c, buf, len);
 	SHA1_Final(sha1, &c);
 
@@ -265,14 +270,22 @@ int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
 	/* Set it up */
 	memset(&stream, 0, sizeof(stream));
 	deflateInit(&stream, Z_BEST_COMPRESSION);
-	size = deflateBound(&stream, len);
+	size = deflateBound(&stream, len+hdrlen);
 	compressed = malloc(size);
 
 	/* Compress it */
-	stream.next_in = buf;
-	stream.avail_in = len;
 	stream.next_out = compressed;
 	stream.avail_out = size;
+
+	/* First header.. */
+	stream.next_in = hdr;
+	stream.avail_in = hdrlen;
+	while (deflate(&stream, 0) == Z_OK)
+		/* nothing */
+
+	/* Then the data itself.. */
+	stream.next_in = buf;
+	stream.avail_in = len;
 	while (deflate(&stream, Z_FINISH) == Z_OK)
 		/* nothing */;
 	deflateEnd(&stream);

write-tree.c

@@ -17,29 +17,17 @@ static int check_valid_sha1(unsigned char *sha1)
 	return ret;
 }
 
-static int prepend_integer(char *buffer, unsigned val, int i)
-{
-	buffer[--i] = '\0';
-	do {
-		buffer[--i] = '0' + (val % 10);
-		val /= 10;
-	} while (val);
-	return i;
-}
-
-#define ORIG_OFFSET (40)	/* Enough space to add the header of "tree <size>\0" */
-
 static int write_tree(struct cache_entry **cachep, int maxentries, const char *base, int baselen, unsigned char *returnsha1)
 {
 	unsigned char subdir_sha1[20];
 	unsigned long size, offset;
 	char *buffer;
-	int i, nr;
+	int nr;
 
 	/* Guess at some random initial size */
 	size = 8192;
 	buffer = malloc(size);
-	offset = ORIG_OFFSET;
+	offset = 0;
 
 	nr = 0;
 	do {
@@ -89,11 +77,7 @@ static int write_tree(struct cache_entry **cachep, int maxentries, const char *b
 		nr++;
 	} while (nr < maxentries);
 
-	i = prepend_integer(buffer, offset - ORIG_OFFSET, ORIG_OFFSET);
-	i -= 5;
-	memcpy(buffer+i, "tree ", 5);
-
-	write_sha1_file(buffer + i, offset - i, returnsha1);
+	write_sha1_file(buffer, offset, "tree", returnsha1);
 	free(buffer);
 	return nr;
 }