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/*
 * GIT - The information manager from hell
 *
 * Copyright (C) Linus Torvalds, 2005
 */
#include "cache.h"
 
static int check_valid_sha1(unsigned char *sha1)
{
	char *filename = sha1_file_name(sha1);
	int ret;
 
	/* If we were anal, we'd check that the sha1 of the contents actually matches */
	ret = access(filename, R_OK);
	if (ret)
		perror(filename);
	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;
 
	/* Guess at some random initial size */
	size = 8192;
	buffer = malloc(size);
	offset = ORIG_OFFSET;
 
	nr = 0;
	do {
		struct cache_entry *ce = cachep[nr];
		const char *pathname = ce->name, *filename, *dirname;
		int pathlen = ce->namelen, entrylen;
		unsigned char *sha1;
		unsigned int mode;
 
		/* Did we hit the end of the directory? Return how many we wrote */
		if (baselen >= pathlen || memcmp(base, pathname, baselen))
			break;
 
		sha1 = ce->sha1;
		mode = ce->st_mode;
 
		/* Do we have _further_ subdirectories? */
		filename = pathname + baselen;
		dirname = strchr(filename, '/');
		if (dirname) {
			int subdir_written;
 
			subdir_written = write_tree(cachep + nr, maxentries - nr, pathname, dirname-pathname+1, subdir_sha1);
			fprintf(stderr, "Wrote %d entries from subdirectory '%.*s'\n", 
				subdir_written, dirname-pathname, pathname);
			nr += subdir_written;
 
			/* Now we need to write out the directory entry into this tree.. */
			mode = S_IFDIR;
			pathlen = dirname - pathname;
 
			/* ..but the directory entry doesn't count towards the total count */
			nr--;
			sha1 = subdir_sha1;
		}
 
		if (check_valid_sha1(sha1) < 0)
			exit(1);
 
		entrylen = pathlen - baselen;
		if (offset + entrylen + 100 > size) {
			size = alloc_nr(offset + entrylen + 100);
			buffer = realloc(buffer, size);
		}
		offset += sprintf(buffer + offset, "%o %.*s", mode, entrylen, filename);
		buffer[offset++] = 0;
		memcpy(buffer + offset, sha1, 20);
		offset += 20;
		nr++;
	} while (nr < maxentries);
 
	i = prepend_integer(buffer, offset - ORIG_OFFSET, ORIG_OFFSET);
	i -= 5;
	memcpy(buffer+i, "tree ", 5);
 
	buffer += i;
	offset -= i;
 
	write_sha1_file(buffer, offset, returnsha1);
	return nr;
}
 
int main(int argc, char **argv)
{
	int entries = read_cache();
	unsigned char sha1[20];
 
	if (entries <= 0)
		usage("no cache contents to write");
	if (write_tree(active_cache, entries, "", 0, sha1) != entries)
		usage("write-tree: internal error");
	printf("%s\n", sha1_to_hex(sha1));
	return 0;
}