1 files changed, 329 insertions, 0 deletions
diff --git a/convert-objects.c b/convert-objects.c
new file mode 100644
index 0000000..90e7900
--- /dev/null
+++ b/convert-objects.c
@@ -0,0 +1,329 @@
+#include "cache.h"
+#include "blob.h"
+#include "commit.h"
+#include "tree.h"
+
+struct entry {
+	unsigned char old_sha1[20];
+	unsigned char new_sha1[20];
+	int converted;
+};
+
+#define MAXOBJECTS (1000000)
+
+static struct entry *convert[MAXOBJECTS];
+static int nr_convert;
+
+static struct entry * convert_entry(unsigned char *sha1);
+
+static struct entry *insert_new(unsigned char *sha1, int pos)
+{
+	struct entry *new = xcalloc(1, sizeof(struct entry));
+	hashcpy(new->old_sha1, sha1);
+	memmove(convert + pos + 1, convert + pos, (nr_convert - pos) * sizeof(struct entry *));
+	convert[pos] = new;
+	nr_convert++;
+	if (nr_convert == MAXOBJECTS)
+		die("you're kidding me - hit maximum object limit");
+	return new;
+}
+
+static struct entry *lookup_entry(unsigned char *sha1)
+{
+	int low = 0, high = nr_convert;
+
+	while (low < high) {
+		int next = (low + high) / 2;
+		struct entry *n = convert[next];
+		int cmp = hashcmp(sha1, n->old_sha1);
+		if (!cmp)
+			return n;
+		if (cmp < 0) {
+			high = next;
+			continue;
+		}
+		low = next+1;
+	}
+	return insert_new(sha1, low);
+}
+
+static void convert_binary_sha1(void *buffer)
+{
+	struct entry *entry = convert_entry(buffer);
+	hashcpy(buffer, entry->new_sha1);
+}
+
+static void convert_ascii_sha1(void *buffer)
+{
+	unsigned char sha1[20];
+	struct entry *entry;
+
+	if (get_sha1_hex(buffer, sha1))
+		die("expected sha1, got '%s'", (char*) buffer);
+	entry = convert_entry(sha1);
+	memcpy(buffer, sha1_to_hex(entry->new_sha1), 40);
+}
+
+static unsigned int convert_mode(unsigned int mode)
+{
+	unsigned int newmode;
+
+	newmode = mode & S_IFMT;
+	if (S_ISREG(mode))
+		newmode |= (mode & 0100) ? 0755 : 0644;
+	return newmode;
+}
+
+static int write_subdirectory(void *buffer, unsigned long size, const char *base, int baselen, unsigned char *result_sha1)
+{
+	char *new = xmalloc(size);
+	unsigned long newlen = 0;
+	unsigned long used;
+
+	used = 0;
+	while (size) {
+		int len = 21 + strlen(buffer);
+		char *path = strchr(buffer, ' ');
+		unsigned char *sha1;
+		unsigned int mode;
+		char *slash, *origpath;
+
+		if (!path || strtoul_ui(buffer, 8, &mode))
+			die("bad tree conversion");
+		mode = convert_mode(mode);
+		path++;
+		if (memcmp(path, base, baselen))
+			break;
+		origpath = path;
+		path += baselen;
+		slash = strchr(path, '/');
+		if (!slash) {
+			newlen += sprintf(new + newlen, "%o %s", mode, path);
+			new[newlen++] = '\0';
+			hashcpy((unsigned char*)new + newlen, (unsigned char *) buffer + len - 20);
+			newlen += 20;
+
+			used += len;
+			size -= len;
+			buffer = (char *) buffer + len;
+			continue;
+		}
+
+		newlen += sprintf(new + newlen, "%o %.*s", S_IFDIR, (int)(slash - path), path);
+		new[newlen++] = 0;
+		sha1 = (unsigned char *)(new + newlen);
+		newlen += 20;
+
+		len = write_subdirectory(buffer, size, origpath, slash-origpath+1, sha1);
+
+		used += len;
+		size -= len;
+		buffer = (char *) buffer + len;
+	}
+
+	write_sha1_file(new, newlen, tree_type, result_sha1);
+	free(new);
+	return used;
+}
+
+static void convert_tree(void *buffer, unsigned long size, unsigned char *result_sha1)
+{
+	void *orig_buffer = buffer;
+	unsigned long orig_size = size;
+
+	while (size) {
+		size_t len = 1+strlen(buffer);
+
+		convert_binary_sha1((char *) buffer + len);
+
+		len += 20;
+		if (len > size)
+			die("corrupt tree object");
+		size -= len;
+		buffer = (char *) buffer + len;
+	}
+
+	write_subdirectory(orig_buffer, orig_size, "", 0, result_sha1);
+}
+
+static unsigned long parse_oldstyle_date(const char *buf)
+{
+	char c, *p;
+	char buffer[100];
+	struct tm tm;
+	const char *formats[] = {
+		"%c",
+		"%a %b %d %T",
+		"%Z",
+		"%Y",
+		" %Y",
+		NULL
+	};
+	/* We only ever did two timezones in the bad old format .. */
+	const char *timezones[] = {
+		"PDT", "PST", "CEST", NULL
+	};
+	const char **fmt = formats;
+
+	p = buffer;
+	while (isspace(c = *buf))
+		buf++;
+	while ((c = *buf++) != '\n')
+		*p++ = c;
+	*p++ = 0;
+	buf = buffer;
+	memset(&tm, 0, sizeof(tm));
+	do {
+		const char *next = strptime(buf, *fmt, &tm);
+		if (next) {
+			if (!*next)
+				return mktime(&tm);
+			buf = next;
+		} else {
+			const char **p = timezones;
+			while (isspace(*buf))
+				buf++;
+			while (*p) {
+				if (!memcmp(buf, *p, strlen(*p))) {
+					buf += strlen(*p);
+					break;
+				}
+				p++;
+			}
+		}
+		fmt++;
+	} while (*buf && *fmt);
+	printf("left: %s\n", buf);
+	return mktime(&tm);
+}
+
+static int convert_date_line(char *dst, void **buf, unsigned long *sp)
+{
+	unsigned long size = *sp;
+	char *line = *buf;
+	char *next = strchr(line, '\n');
+	char *date = strchr(line, '>');
+	int len;
+
+	if (!next || !date)
+		die("missing or bad author/committer line %s", line);
+	next++; date += 2;
+
+	*buf = next;
+	*sp = size - (next - line);
+
+	len = date - line;
+	memcpy(dst, line, len);
+	dst += len;
+
+	/* Is it already in new format? */
+	if (isdigit(*date)) {
+		int datelen = next - date;
+		memcpy(dst, date, datelen);
+		return len + datelen;
+	}
+
+	/*
+	 * Hacky hacky: one of the sparse old-style commits does not have
+	 * any date at all, but we can fake it by using the committer date.
+	 */
+	if (*date == '\n' && strchr(next, '>'))
+		date = strchr(next, '>')+2;
+
+	return len + sprintf(dst, "%lu -0700\n", parse_oldstyle_date(date));
+}
+
+static void convert_date(void *buffer, unsigned long size, unsigned char *result_sha1)
+{
+	char *new = xmalloc(size + 100);
+	unsigned long newlen = 0;
+
+	/* "tree <sha1>\n" */
+	memcpy(new + newlen, buffer, 46);
+	newlen += 46;
+	buffer = (char *) buffer + 46;
+	size -= 46;
+
+	/* "parent <sha1>\n" */
+	while (!memcmp(buffer, "parent ", 7)) {
+		memcpy(new + newlen, buffer, 48);
+		newlen += 48;
+		buffer = (char *) buffer + 48;
+		size -= 48;
+	}
+
+	/* "author xyz <xyz> date" */
+	newlen += convert_date_line(new + newlen, &buffer, &size);
+	/* "committer xyz <xyz> date" */
+	newlen += convert_date_line(new + newlen, &buffer, &size);
+
+	/* Rest */
+	memcpy(new + newlen, buffer, size);
+	newlen += size;
+
+	write_sha1_file(new, newlen, commit_type, result_sha1);
+	free(new);
+}
+
+static void convert_commit(void *buffer, unsigned long size, unsigned char *result_sha1)
+{
+	void *orig_buffer = buffer;
+	unsigned long orig_size = size;
+
+	if (memcmp(buffer, "tree ", 5))
+		die("Bad commit '%s'", (char*) buffer);
+	convert_ascii_sha1((char *) buffer + 5);
+	buffer = (char *) buffer + 46;    /* "tree " + "hex sha1" + "\n" */
+	while (!memcmp(buffer, "parent ", 7)) {
+		convert_ascii_sha1((char *) buffer + 7);
+		buffer = (char *) buffer + 48;
+	}
+	convert_date(orig_buffer, orig_size, result_sha1);
+}
+
+static struct entry * convert_entry(unsigned char *sha1)
+{
+	struct entry *entry = lookup_entry(sha1);
+	enum object_type type;
+	void *buffer, *data;
+	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 = xmalloc(size);
+	memcpy(buffer, data, size);
+
+	if (type == OBJ_BLOB) {
+		write_sha1_file(buffer, size, blob_type, entry->new_sha1);
+	} else if (type == OBJ_TREE)
+		convert_tree(buffer, size, entry->new_sha1);
+	else if (type == OBJ_COMMIT)
+		convert_commit(buffer, size, entry->new_sha1);
+	else
+		die("unknown object type %d in %s", type, sha1_to_hex(sha1));
+	entry->converted = 1;
+	free(buffer);
+	free(data);
+	return entry;
+}
+
+int main(int argc, char **argv)
+{
+	unsigned char sha1[20];
+	struct entry *entry;
+
+	setup_git_directory();
+
+	if (argc != 2)
+		usage("git-convert-objects <sha1>");
+	if (get_sha1(argv[1], sha1))
+		die("Not a valid object name %s", argv[1]);
+
+	entry = convert_entry(sha1);
+	printf("new sha1: %s\n", sha1_to_hex(entry->new_sha1));
+	return 0;
+}