1 files changed, 161 insertions, 224 deletions

diff --git a/tar-tree.c b/tar-tree.c
index 92035f5..8d9e31c 100644
--- a/tar-tree.c
+++ b/tar-tree.c
@@ -1,37 +1,23 @@
 /*
- * Copyright (c) 2005 Rene Scharfe
+ * Copyright (c) 2005, 2006 Rene Scharfe
  */
 #include <time.h>
 #include "cache.h"
 #include "diff.h"
 #include "commit.h"
+#include "strbuf.h"
+#include "tar.h"
 
 #define RECORDSIZE	(512)
 #define BLOCKSIZE	(RECORDSIZE * 20)
 
-#define TYPEFLAG_AUTO		'\0'
-#define TYPEFLAG_REG		'0'
-#define TYPEFLAG_LNK		'2'
-#define TYPEFLAG_DIR		'5'
-#define TYPEFLAG_GLOBAL_HEADER	'g'
-#define TYPEFLAG_EXT_HEADER	'x'
-
-#define EXT_HEADER_PATH		1
-#define EXT_HEADER_LINKPATH	2
-
 static const char tar_tree_usage[] = "git-tar-tree <key> [basedir]";
 
 static char block[BLOCKSIZE];
 static unsigned long offset;
 
-static const char *basedir;
 static time_t archive_time;
 
-struct path_prefix {
-	struct path_prefix *prev;
-	const char *name;
-};
-
 /* tries hard to write, either succeeds or dies in the attempt */
 static void reliable_write(void *buf, unsigned long size)
 {
@@ -119,230 +105,170 @@ static void write_blocked(void *buf, unsigned long size)
 	write_if_needed();
 }
 
-static void append_string(char **p, const char *s)
-{
-	unsigned int len = strlen(s);
-	memcpy(*p, s, len);
-	*p += len;
-}
-
-static void append_char(char **p, char c)
-{
-	**p = c;
-	*p += 1;
-}
-
-static void append_path_prefix(char **buffer, struct path_prefix *prefix)
+static void strbuf_append_string(struct strbuf *sb, const char *s)
 {
-	if (!prefix)
-		return;
-	append_path_prefix(buffer, prefix->prev);
-	append_string(buffer, prefix->name);
-	append_char(buffer, '/');
-}
-
-static unsigned int path_prefix_len(struct path_prefix *prefix)
-{
-	if (!prefix)
-		return 0;
-	return path_prefix_len(prefix->prev) + strlen(prefix->name) + 1;
-}
-
-static void append_path(char **p, int is_dir, const char *basepath,
-                        struct path_prefix *prefix, const char *path)
-{
-	if (basepath) {
-		append_string(p, basepath);
-		append_char(p, '/');
+	int slen = strlen(s);
+	int total = sb->len + slen;
+	if (total > sb->alloc) {
+		sb->buf = xrealloc(sb->buf, total);
+		sb->alloc = total;
 	}
-	append_path_prefix(p, prefix);
-	append_string(p, path);
-	if (is_dir)
-		append_char(p, '/');
+	memcpy(sb->buf + sb->len, s, slen);
+	sb->len = total;
 }
 
-static unsigned int path_len(int is_dir, const char *basepath,
-                             struct path_prefix *prefix, const char *path)
-{
-	unsigned int len = 0;
-	if (basepath)
-		len += strlen(basepath) + 1;
-	len += path_prefix_len(prefix) + strlen(path);
-	if (is_dir)
-		len++;
-	return len;
-}
-
-static void append_extended_header_prefix(char **p, unsigned int size,
-                                          const char *keyword)
+/*
+ * pax extended header records have the format "%u %s=%s\n".  %u contains
+ * the size of the whole string (including the %u), the first %s is the
+ * keyword, the second one is the value.  This function constructs such a
+ * string and appends it to a struct strbuf.
+ */
+static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
+                                     const char *value, unsigned int valuelen)
 {
-	int len = sprintf(*p, "%u %s=", size, keyword);
-	*p += len;
-}
+	char *p;
+	int len, total, tmp;
 
-static unsigned int extended_header_len(const char *keyword,
-                                        unsigned int valuelen)
-{
 	/* "%u %s=%s\n" */
-	unsigned int len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
-	if (len > 9)
-		len++;
-	if (len > 99)
+	len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
+	for (tmp = len; tmp > 9; tmp /= 10)
 		len++;
-	return len;
-}
 
-static void append_extended_header(char **p, const char *keyword,
-                                   const char *value, unsigned int len)
-{
-	unsigned int size = extended_header_len(keyword, len);
-	append_extended_header_prefix(p, size, keyword);
-	memcpy(*p, value, len);
-	*p += len;
-	append_char(p, '\n');
-}
+	total = sb->len + len;
+	if (total > sb->alloc) {
+		sb->buf = xrealloc(sb->buf, total);
+		sb->alloc = total;
+	}
 
-static void write_header(const unsigned char *, char, const char *, struct path_prefix *,
-                         const char *, unsigned int, void *, unsigned long);
+	p = sb->buf;
+	p += sprintf(p, "%u %s=", len, keyword);
+	memcpy(p, value, valuelen);
+	p += valuelen;
+	*p = '\n';
+	sb->len = total;
+}
 
-/* stores a pax extended header directly in the block buffer */
-static void write_extended_header(const char *headerfilename, int is_dir,
-                                  unsigned int flags, const char *basepath,
-                                  struct path_prefix *prefix,
-                                  const char *path, unsigned int namelen,
-                                  void *content, unsigned int contentsize)
+static unsigned int ustar_header_chksum(const struct ustar_header *header)
 {
-	char *buffer, *p;
-	unsigned int pathlen, size, linkpathlen = 0;
-
-	size = pathlen = extended_header_len("path", namelen);
-	if (flags & EXT_HEADER_LINKPATH) {
-		linkpathlen = extended_header_len("linkpath", contentsize);
-		size += linkpathlen;
-	}
-	write_header(NULL, TYPEFLAG_EXT_HEADER, NULL, NULL, headerfilename,
-	             0100600, NULL, size);
-
-	buffer = p = malloc(size);
-	if (!buffer)
-		die("git-tar-tree: %s", strerror(errno));
-	append_extended_header_prefix(&p, pathlen, "path");
-	append_path(&p, is_dir, basepath, prefix, path);
-	append_char(&p, '\n');
-	if (flags & EXT_HEADER_LINKPATH)
-		append_extended_header(&p, "linkpath", content, contentsize);
-	write_blocked(buffer, size);
-	free(buffer);
+	char *p = (char *)header;
+	unsigned int chksum = 0;
+	while (p < header->chksum)
+		chksum += *p++;
+	chksum += sizeof(header->chksum) * ' ';
+	p += sizeof(header->chksum);
+	while (p < (char *)header + sizeof(struct ustar_header))
+		chksum += *p++;
+	return chksum;
 }
 
-static void write_global_extended_header(const unsigned char *sha1)
+static int get_path_prefix(const struct strbuf *path, int maxlen)
 {
-	char *p;
-	unsigned int size;
-
-	size = extended_header_len("comment", 40);
-	write_header(NULL, TYPEFLAG_GLOBAL_HEADER, NULL, NULL,
-	             "pax_global_header", 0100600, NULL, size);
-
-	p = get_record();
-	append_extended_header(&p, "comment", sha1_to_hex(sha1), 40);
-	write_if_needed();
+	int i = path->len;
+	if (i > maxlen)
+		i = maxlen;
+	while (i > 0 && path->buf[i] != '/')
+		i--;
+	return i;
 }
 
-/* stores a ustar header directly in the block buffer */
-static void write_header(const unsigned char *sha1, char typeflag, const char *basepath,
-                         struct path_prefix *prefix, const char *path,
-                         unsigned int mode, void *buffer, unsigned long size)
+static void write_entry(const unsigned char *sha1, struct strbuf *path,
+                        unsigned int mode, void *buffer, unsigned long size)
 {
-	unsigned int namelen; 
-	char *header = NULL;
-	unsigned int checksum = 0;
-	int i;
-	unsigned int ext_header = 0;
-
-	if (typeflag == TYPEFLAG_AUTO) {
-		if (S_ISDIR(mode))
-			typeflag = TYPEFLAG_DIR;
-		else if (S_ISLNK(mode))
-			typeflag = TYPEFLAG_LNK;
-		else
-			typeflag = TYPEFLAG_REG;
-	}
-
-	namelen = path_len(S_ISDIR(mode), basepath, prefix, path);
-	if (namelen > 100)
-		ext_header |= EXT_HEADER_PATH;
-	if (typeflag == TYPEFLAG_LNK && size > 100)
-		ext_header |= EXT_HEADER_LINKPATH;
-
-	/* the extended header must be written before the normal one */
-	if (ext_header) {
-		char headerfilename[51];
-		sprintf(headerfilename, "%s.paxheader", sha1_to_hex(sha1));
-		write_extended_header(headerfilename, S_ISDIR(mode),
-		                      ext_header, basepath, prefix, path,
-		                      namelen, buffer, size);
-	}
-
-	header = get_record();
-
-	if (ext_header) {
-		sprintf(header, "%s.data", sha1_to_hex(sha1));
+	struct ustar_header header;
+	struct strbuf ext_header;
+
+	memset(&header, 0, sizeof(header));
+	ext_header.buf = NULL;
+	ext_header.len = ext_header.alloc = 0;
+
+	if (!sha1) {
+		*header.typeflag = TYPEFLAG_GLOBAL_HEADER;
+		mode = 0100666;
+		strcpy(header.name, "pax_global_header");
+	} else if (!path) {
+		*header.typeflag = TYPEFLAG_EXT_HEADER;
+		mode = 0100666;
+		sprintf(header.name, "%s.paxheader", sha1_to_hex(sha1));
 	} else {
-		char *p = header;
-		append_path(&p, S_ISDIR(mode), basepath, prefix, path);
+		if (S_ISDIR(mode)) {
+			*header.typeflag = TYPEFLAG_DIR;
+			mode |= 0777;
+		} else if (S_ISLNK(mode)) {
+			*header.typeflag = TYPEFLAG_LNK;
+			mode |= 0777;
+		} else if (S_ISREG(mode)) {
+			*header.typeflag = TYPEFLAG_REG;
+			mode |= (mode & 0100) ? 0777 : 0666;
+		} else {
+			error("unsupported file mode: 0%o (SHA1: %s)",
+			      mode, sha1_to_hex(sha1));
+			return;
+		}
+		if (path->len > sizeof(header.name)) {
+			int plen = get_path_prefix(path, sizeof(header.prefix));
+			int rest = path->len - plen - 1;
+			if (plen > 0 && rest <= sizeof(header.name)) {
+				memcpy(header.prefix, path->buf, plen);
+				memcpy(header.name, path->buf + plen + 1, rest);
+			} else {
+				sprintf(header.name, "%s.data",
+				        sha1_to_hex(sha1));
+				strbuf_append_ext_header(&ext_header, "path",
+				                         path->buf, path->len);
+			}
+		} else
+			memcpy(header.name, path->buf, path->len);
 	}
 
-	if (typeflag == TYPEFLAG_LNK) {
-		if (ext_header & EXT_HEADER_LINKPATH) {
-			sprintf(&header[157], "see %s.paxheader",
+	if (S_ISLNK(mode) && buffer) {
+		if (size > sizeof(header.linkname)) {
+			sprintf(header.linkname, "see %s.paxheader",
 			        sha1_to_hex(sha1));
-		} else {
-			if (buffer)
-				strncpy(&header[157], buffer, size);
-		}
+			strbuf_append_ext_header(&ext_header, "linkpath",
+			                         buffer, size);
+		} else
+			memcpy(header.linkname, buffer, size);
 	}
 
-	if (S_ISDIR(mode))
-		mode |= 0777;
-	else if (S_ISREG(mode))
-		mode |= (mode & 0100) ? 0777 : 0666;
-	else if (S_ISLNK(mode))
-		mode |= 0777;
-	sprintf(&header[100], "%07o", mode & 07777);
+	sprintf(header.mode, "%07o", mode & 07777);
+	sprintf(header.size, "%011lo", S_ISREG(mode) ? size : 0);
+	sprintf(header.mtime, "%011lo", archive_time);
 
 	/* XXX: should we provide more meaningful info here? */
-	sprintf(&header[108], "%07o", 0);	/* uid */
-	sprintf(&header[116], "%07o", 0);	/* gid */
-	strncpy(&header[265], "git", 31);	/* uname */
-	strncpy(&header[297], "git", 31);	/* gname */
-
-	if (S_ISDIR(mode) || S_ISLNK(mode))
-		size = 0;
-	sprintf(&header[124], "%011lo", size);
-	sprintf(&header[136], "%011lo", archive_time);
+	sprintf(header.uid, "%07o", 0);
+	sprintf(header.gid, "%07o", 0);
+	strncpy(header.uname, "git", 31);
+	strncpy(header.gname, "git", 31);
+	sprintf(header.devmajor, "%07o", 0);
+	sprintf(header.devminor, "%07o", 0);
 
-	header[156] = typeflag;
+	memcpy(header.magic, "ustar", 6);
+	memcpy(header.version, "00", 2);
 
-	memcpy(&header[257], "ustar", 6);
-	memcpy(&header[263], "00", 2);
+	sprintf(header.chksum, "%07o", ustar_header_chksum(&header));
 
-	sprintf(&header[329], "%07o", 0);	/* devmajor */
-	sprintf(&header[337], "%07o", 0);	/* devminor */
-
-	memset(&header[148], ' ', 8);
-	for (i = 0; i < RECORDSIZE; i++)
-		checksum += header[i];
-	sprintf(&header[148], "%07o", checksum & 0x1fffff);
+	if (ext_header.len > 0) {
+		write_entry(sha1, NULL, 0, ext_header.buf, ext_header.len);
+		free(ext_header.buf);
+	}
+	write_blocked(&header, sizeof(header));
+	if (S_ISREG(mode) && buffer && size > 0)
+		write_blocked(buffer, size);
+}
 
-	write_if_needed();
+static void write_global_extended_header(const unsigned char *sha1)
+{
+	struct strbuf ext_header;
+	ext_header.buf = NULL;
+	ext_header.len = ext_header.alloc = 0;
+	strbuf_append_ext_header(&ext_header, "comment", sha1_to_hex(sha1), 40);
+	write_entry(NULL, NULL, 0, ext_header.buf, ext_header.len);
+	free(ext_header.buf);
 }
 
-static void traverse_tree(struct tree_desc *tree,
-			  struct path_prefix *prefix)
+static void traverse_tree(struct tree_desc *tree, struct strbuf *path)
 {
-	struct path_prefix this_prefix;
-	this_prefix.prev = prefix;
+	int pathlen = path->len;
 
 	while (tree->size) {
 		const char *name;
@@ -358,16 +284,19 @@ static void traverse_tree(struct tree_desc *tree,
 		eltbuf = read_sha1_file(sha1, elttype, &eltsize);
 		if (!eltbuf)
 			die("cannot read %s", sha1_to_hex(sha1));
-		write_header(sha1, TYPEFLAG_AUTO, basedir, 
-			     prefix, name, mode, eltbuf, eltsize);
+
+		path->len = pathlen;
+		strbuf_append_string(path, name);
+		if (S_ISDIR(mode))
+			strbuf_append_string(path, "/");
+
+		write_entry(sha1, path, mode, eltbuf, eltsize);
+
 		if (S_ISDIR(mode)) {
 			struct tree_desc subtree;
 			subtree.buf = eltbuf;
 			subtree.size = eltsize;
-			this_prefix.name = name;
-			traverse_tree(&subtree, &this_prefix);
-		} else if (!S_ISLNK(mode)) {
-			write_blocked(eltbuf, eltsize);
+			traverse_tree(&subtree, path);
 		}
 		free(eltbuf);
 	}
@@ -375,16 +304,22 @@ static void traverse_tree(struct tree_desc *tree,
 
 int main(int argc, char **argv)
 {
-	unsigned char sha1[20];
+	unsigned char sha1[20], tree_sha1[20];
 	struct commit *commit;
 	struct tree_desc tree;
+	struct strbuf current_path;
+
+	current_path.buf = xmalloc(PATH_MAX);
+	current_path.alloc = PATH_MAX;
+	current_path.len = current_path.eof = 0;
 
 	setup_git_directory();
 	git_config(git_default_config);
 
 	switch (argc) {
 	case 3:
-		basedir = argv[2];
+		strbuf_append_string(&current_path, argv[2]);
+		strbuf_append_string(&current_path, "/");
 		/* FALLTHROUGH */
 	case 2:
 		if (get_sha1(argv[1], sha1) < 0)
@@ -398,17 +333,19 @@ int main(int argc, char **argv)
 	if (commit) {
 		write_global_extended_header(commit->object.sha1);
 		archive_time = commit->date;
-	}
-	tree.buf = read_object_with_reference(sha1, "tree", &tree.size, NULL);
+	} else
+		archive_time = time(NULL);
+
+	tree.buf = read_object_with_reference(sha1, "tree", &tree.size,
+	                                      tree_sha1);
 	if (!tree.buf)
 		die("not a reference to a tag, commit or tree object: %s",
 		    sha1_to_hex(sha1));
-	if (!archive_time)
-		archive_time = time(NULL);
-	if (basedir)
-		write_header((unsigned char *)"0", TYPEFLAG_DIR, NULL, NULL,
-			basedir, 040777, NULL, 0);
-	traverse_tree(&tree, NULL);
+
+	if (current_path.len > 0)
+		write_entry(tree_sha1, &current_path, 040777, NULL, 0);
+	traverse_tree(&tree, &current_path);
 	write_trailer();
+	free(current_path.buf);
 	return 0;
 }