thodg/libgit2/src/indexer.c

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• Hash : 18e5b854
  Author :
  Date : 2012-02-10T19:47:02
  

  odb: Add internal `git_odb__hashfd`

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• src/indexer.c

• /*
   * Copyright (C) 2009-2011 the libgit2 contributors
   *
   * This file is part of libgit2, distributed under the GNU GPL v2 with
   * a Linking Exception. For full terms see the included COPYING file.
   */
  
  #include "git2/indexer.h"
  #include "git2/object.h"
  #include "git2/zlib.h"
  #include "git2/oid.h"
  
  #include "common.h"
  #include "pack.h"
  #include "mwindow.h"
  #include "posix.h"
  #include "pack.h"
  #include "filebuf.h"
  #include "sha1.h"
  
  #define UINT31_MAX (0x7FFFFFFF)
  
  struct entry {
  	git_oid oid;
  	uint32_t crc;
  	uint32_t offset;
  	uint64_t offset_long;
  };
  
  struct git_indexer {
  	struct git_pack_file *pack;
  	struct stat st;
  	struct git_pack_header hdr;
  	size_t nr_objects;
  	git_vector objects;
  	git_filebuf file;
  	unsigned int fanout[256];
  	git_oid hash;
  };
  
  const git_oid *git_indexer_hash(git_indexer *idx)
  {
  	return &idx->hash;
  }
  
  static int parse_header(git_indexer *idx)
  {
  	int error;
  
  	/* Verify we recognize this pack file format. */
  	if ((error = p_read(idx->pack->mwf.fd, &idx->hdr, sizeof(idx->hdr))) < GIT_SUCCESS)
  		return git__rethrow(error, "Failed to read in pack header");
  
  	if (idx->hdr.hdr_signature != ntohl(PACK_SIGNATURE))
  		return git__throw(GIT_EOBJCORRUPTED, "Wrong pack signature");
  
  	if (!pack_version_ok(idx->hdr.hdr_version))
  		return git__throw(GIT_EOBJCORRUPTED, "Wrong pack version");
  
  
  	return GIT_SUCCESS;
  }
  
  static int objects_cmp(const void *a, const void *b)
  {
  	const struct entry *entrya = a;
  	const struct entry *entryb = b;
  
  	return git_oid_cmp(&entrya->oid, &entryb->oid);
  }
  
  static int cache_cmp(const void *a, const void *b)
  {
  	const struct git_pack_entry *ea = a;
  	const struct git_pack_entry *eb = b;
  
  	return git_oid_cmp(&ea->sha1, &eb->sha1);
  }
  
  
  int git_indexer_new(git_indexer **out, const char *packname)
  {
  	git_indexer *idx;
  	size_t namelen;
  	int ret, error;
  
  	assert(out && packname);
  
  	if (git_path_root(packname) < 0)
  		return git__throw(GIT_EINVALIDPATH, "Path is not absolute");
  
  	idx = git__malloc(sizeof(git_indexer));
  	if (idx == NULL)
  		return GIT_ENOMEM;
  
  	memset(idx, 0x0, sizeof(*idx));
  
  	namelen = strlen(packname);
  	idx->pack = git__malloc(sizeof(struct git_pack_file) + namelen + 1);
  	if (idx->pack == NULL) {
  		error = GIT_ENOMEM;
  		goto cleanup;
  	}
  
  	memset(idx->pack, 0x0, sizeof(struct git_pack_file));
  	memcpy(idx->pack->pack_name, packname, namelen + 1);
  
  	ret = p_stat(packname, &idx->st);
  	if (ret < 0) {
  		if (errno == ENOENT)
  			error = git__throw(GIT_ENOTFOUND, "Failed to stat packfile. File not found");
  		else
  			error = git__throw(GIT_EOSERR, "Failed to stat packfile.");
  
  		goto cleanup;
  	}
  
  	ret = p_open(idx->pack->pack_name, O_RDONLY);
  	if (ret < 0) {
  		error = git__throw(GIT_EOSERR, "Failed to open packfile");
  		goto cleanup;
  	}
  
  	idx->pack->mwf.fd = ret;
  	idx->pack->mwf.size = (git_off_t)idx->st.st_size;
  
  	error = parse_header(idx);
  	if (error < GIT_SUCCESS) {
  		error = git__rethrow(error, "Failed to parse packfile header");
  		goto cleanup;
  	}
  
  	idx->nr_objects = ntohl(idx->hdr.hdr_entries);
  
  	error = git_vector_init(&idx->pack->cache, idx->nr_objects, cache_cmp);
  	if (error < GIT_SUCCESS)
  		goto cleanup;
  
  	idx->pack->has_cache = 1;
  	error = git_vector_init(&idx->objects, idx->nr_objects, objects_cmp);
  	if (error < GIT_SUCCESS)
  		goto cleanup;
  
  	*out = idx;
  
  	return GIT_SUCCESS;
  
  cleanup:
  	git_indexer_free(idx);
  
  	return error;
  }
  
  static int index_path(git_buf *path, git_indexer *idx)
  {
  	const char prefix[] = "pack-", suffix[] = ".idx";
  	size_t slash = (size_t)path->size;
  
  	/* search backwards for '/' */
  	while (slash > 0 && path->ptr[slash - 1] != '/')
  		slash--;
  
  	if (git_buf_grow(path, slash + 1 + strlen(prefix) +
  					 GIT_OID_HEXSZ + strlen(suffix) + 1) < GIT_SUCCESS)
  		return GIT_ENOMEM;
  
  	git_buf_truncate(path, slash);
  	git_buf_puts(path, prefix);
  	git_oid_fmt(path->ptr + path->size, &idx->hash);
  	path->size += GIT_OID_HEXSZ;
  	git_buf_puts(path, suffix);
  
  	return git_buf_lasterror(path);
  }
  
  int git_indexer_write(git_indexer *idx)
  {
  	git_mwindow *w = NULL;
  	int error;
  	unsigned int i, long_offsets = 0, left;
  	struct git_pack_idx_header hdr;
  	git_buf filename = GIT_BUF_INIT;
  	struct entry *entry;
  	void *packfile_hash;
  	git_oid file_hash;
  	SHA_CTX ctx;
  
  	git_vector_sort(&idx->objects);
  
  	git_buf_sets(&filename, idx->pack->pack_name);
  	git_buf_truncate(&filename, filename.size - strlen("pack"));
  	git_buf_puts(&filename, "idx");
  
  	if ((error = git_buf_lasterror(&filename)) < GIT_SUCCESS)
  		goto cleanup;
  
  	error = git_filebuf_open(&idx->file, filename.ptr, GIT_FILEBUF_HASH_CONTENTS);
  	if (error < GIT_SUCCESS)
  		goto cleanup;
  
  	/* Write out the header */
  	hdr.idx_signature = htonl(PACK_IDX_SIGNATURE);
  	hdr.idx_version = htonl(2);
  	error = git_filebuf_write(&idx->file, &hdr, sizeof(hdr));
  	if (error < GIT_SUCCESS)
  		goto cleanup;
  
  	/* Write out the fanout table */
  	for (i = 0; i < 256; ++i) {
  		uint32_t n = htonl(idx->fanout[i]);
  		error = git_filebuf_write(&idx->file, &n, sizeof(n));
  		if (error < GIT_SUCCESS)
  			goto cleanup;
  	}
  
  	/* Write out the object names (SHA-1 hashes) */
  	SHA1_Init(&ctx);
  	git_vector_foreach(&idx->objects, i, entry) {
  		error = git_filebuf_write(&idx->file, &entry->oid, sizeof(git_oid));
  		SHA1_Update(&ctx, &entry->oid, GIT_OID_RAWSZ);
  		if (error < GIT_SUCCESS)
  			goto cleanup;
  	}
  	SHA1_Final(idx->hash.id, &ctx);
  
  	/* Write out the CRC32 values */
  	git_vector_foreach(&idx->objects, i, entry) {
  		error = git_filebuf_write(&idx->file, &entry->crc, sizeof(uint32_t));
  		if (error < GIT_SUCCESS)
  			goto cleanup;
  	}
  
  	/* Write out the offsets */
  	git_vector_foreach(&idx->objects, i, entry) {
  		uint32_t n;
  
  		if (entry->offset == UINT32_MAX)
  			n = htonl(0x80000000 | long_offsets++);
  		else
  			n = htonl(entry->offset);
  
  		error = git_filebuf_write(&idx->file, &n, sizeof(uint32_t));
  		if (error < GIT_SUCCESS)
  			goto cleanup;
  	}
  
  	/* Write out the long offsets */
  	git_vector_foreach(&idx->objects, i, entry) {
  		uint32_t split[2];
  
  		if (entry->offset != UINT32_MAX)
  			continue;
  
  		split[0] = htonl(entry->offset_long >> 32);
  		split[1] = htonl(entry->offset_long & 0xffffffff);
  
  		error = git_filebuf_write(&idx->file, &split, sizeof(uint32_t) * 2);
  		if (error < GIT_SUCCESS)
  			goto cleanup;
  	}
  
  	/* Write out the packfile trailer */
  
  	packfile_hash = git_mwindow_open(&idx->pack->mwf, &w, idx->st.st_size - GIT_OID_RAWSZ, GIT_OID_RAWSZ, &left);
  	git_mwindow_close(&w);
  	if (packfile_hash == NULL) {
  		error = git__rethrow(GIT_ENOMEM, "Failed to open window to packfile hash");
  		goto cleanup;
  	}
  
  	memcpy(&file_hash, packfile_hash, GIT_OID_RAWSZ);
  
  	git_mwindow_close(&w);
  
  	error = git_filebuf_write(&idx->file, &file_hash, sizeof(git_oid));
  
  	/* Write out the index sha */
  	error = git_filebuf_hash(&file_hash, &idx->file);
  	if (error < GIT_SUCCESS)
  		goto cleanup;
  
  	error = git_filebuf_write(&idx->file, &file_hash, sizeof(git_oid));
  	if (error < GIT_SUCCESS)
  		goto cleanup;
  
  	/* Figure out what the final name should be */
  	error = index_path(&filename, idx);
  	if (error < GIT_SUCCESS)
  		goto cleanup;
  
  	/* Commit file */
  	error = git_filebuf_commit_at(&idx->file, filename.ptr, GIT_PACK_FILE_MODE);
  
  cleanup:
  	git_mwindow_free_all(&idx->pack->mwf);
  	if (error < GIT_SUCCESS)
  		git_filebuf_cleanup(&idx->file);
  	git_buf_free(&filename);
  
  	return error;
  }
  
  int git_indexer_run(git_indexer *idx, git_indexer_stats *stats)
  {
  	git_mwindow_file *mwf;
  	off_t off = sizeof(struct git_pack_header);
  	int error;
  	struct entry *entry;
  	unsigned int left, processed;
  
  	assert(idx && stats);
  
  	mwf = &idx->pack->mwf;
  	error = git_mwindow_file_register(mwf);
  	if (error < GIT_SUCCESS)
  		return git__rethrow(error, "Failed to register mwindow file");
  
  	stats->total = idx->nr_objects;
  	stats->processed = processed = 0;
  
  	while (processed < idx->nr_objects) {
  		git_rawobj obj;
  		git_oid oid;
  		struct git_pack_entry *pentry;
  		git_mwindow *w = NULL;
  		int i;
  		off_t entry_start = off;
  		void *packed;
  		size_t entry_size;
  
  		entry = git__malloc(sizeof(struct entry));
  		memset(entry, 0x0, sizeof(struct entry));
  
  		if (off > UINT31_MAX) {
  			entry->offset = UINT32_MAX;
  			entry->offset_long = off;
  		} else {
  			entry->offset = off;
  		}
  
  		error = git_packfile_unpack(&obj, idx->pack, &off);
  		if (error < GIT_SUCCESS) {
  			error = git__rethrow(error, "Failed to unpack object");
  			goto cleanup;
  		}
  
  		/* FIXME: Parse the object instead of hashing it */
  		error = git_odb__hashobj(&oid, &obj);
  		if (error < GIT_SUCCESS) {
  			error = git__rethrow(error, "Failed to hash object");
  			goto cleanup;
  		}
  
  		pentry = git__malloc(sizeof(struct git_pack_entry));
  		if (pentry == NULL) {
  			error = GIT_ENOMEM;
  			goto cleanup;
  		}
  		git_oid_cpy(&pentry->sha1, &oid);
  		pentry->offset = entry_start;
  		error = git_vector_insert(&idx->pack->cache, pentry);
  		if (error < GIT_SUCCESS)
  			goto cleanup;
  
  		git_oid_cpy(&entry->oid, &oid);
  		entry->crc = crc32(0L, Z_NULL, 0);
  
  		entry_size = off - entry_start;
  		packed = git_mwindow_open(mwf, &w, entry_start, entry_size, &left);
  		if (packed == NULL) {
  			error = git__rethrow(error, "Failed to open window to read packed data");
  			goto cleanup;
  		}
  		entry->crc = htonl(crc32(entry->crc, packed, entry_size));
  		git_mwindow_close(&w);
  
  		/* Add the object to the list */
  		error = git_vector_insert(&idx->objects, entry);
  		if (error < GIT_SUCCESS) {
  			error = git__rethrow(error, "Failed to add entry to list");
  			goto cleanup;
  		}
  
  		for (i = oid.id[0]; i < 256; ++i) {
  			idx->fanout[i]++;
  		}
  
  		git__free(obj.data);
  
  		stats->processed = ++processed;
  	}
  
  cleanup:
  	git_mwindow_free_all(mwf);
  
  	return error;
  
  }
  
  void git_indexer_free(git_indexer *idx)
  {
  	unsigned int i;
  	struct entry *e;
  	struct git_pack_entry *pe;
  
  	if (idx == NULL)
  		return;
  
  	p_close(idx->pack->mwf.fd);
  	git_vector_foreach(&idx->objects, i, e)
  		git__free(e);
  	git_vector_free(&idx->objects);
  	git_vector_foreach(&idx->pack->cache, i, pe)
  		git__free(pe);
  	git_vector_free(&idx->pack->cache);
  	git__free(idx->pack);
  	git__free(idx);
  }
  
  

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