thodg/libgit2/src/filebuf.c

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• Hash : 86194b24
  Author :
  Date : 2011-02-18T21:57:53
  

  Split packed from unpacked references These two reference types are now stored separately to eventually allow the removal/renaming of loose references and rewriting of the refs packfile. Signed-off-by: Vicent Marti <tanoku@gmail.com>

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• src/filebuf.c

• /*
   * This file is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License, version 2,
   * as published by the Free Software Foundation.
   *
   * In addition to the permissions in the GNU General Public License,
   * the authors give you unlimited permission to link the compiled
   * version of this file into combinations with other programs,
   * and to distribute those combinations without any restriction
   * coming from the use of this file.  (The General Public License
   * restrictions do apply in other respects; for example, they cover
   * modification of the file, and distribution when not linked into
   * a combined executable.)
   *
   * This file is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; see the file COPYING.  If not, write to
   * the Free Software Foundation, 51 Franklin Street, Fifth Floor,
   * Boston, MA 02110-1301, USA.
   */
  #include <stdarg.h>
  
  #include "common.h"
  #include "filebuf.h"
  #include "fileops.h"
  
  static const size_t WRITE_BUFFER_SIZE = (4096 * 2);
  
  static int lock_file(git_filebuf *file, int flags)
  {
  	if (gitfo_exists(file->path_lock) == 0) {
  		if (flags & GIT_FILEBUF_FORCE)
  			gitfo_unlink(file->path_lock);
  		else
  			return GIT_EOSERR;
  	}
  
  	file->fd = gitfo_creat(file->path_lock, 0644);
  
  	if (file->fd < 0)
  		return GIT_EOSERR;
  
  	/* TODO: do a flock() in the descriptor file_lock */
  
  	if ((flags & GIT_FILEBUF_APPEND) && gitfo_exists(file->path_original) == 0) {
  		git_file source;
  		char buffer[2048];
  		size_t read_bytes;
  
  		source = gitfo_open(file->path_original, O_RDONLY);
  		if (source < 0)
  			return GIT_EOSERR;
  
  		while ((read_bytes = gitfo_read(source, buffer, 2048)) > 0) {
  			gitfo_write(file->fd, buffer, read_bytes);
  			if (file->digest)
  				git_hash_update(file->digest, buffer, read_bytes);
  		}
  
  		gitfo_close(source);
  	}
  
  	return GIT_SUCCESS;
  }
  
  void git_filebuf_cleanup(git_filebuf *file)
  {
  	if (file->fd >= 0)
  		gitfo_close(file->fd);
  
  	if (gitfo_exists(file->path_lock) == GIT_SUCCESS)
  		gitfo_unlink(file->path_lock);
  
  	if (file->digest)
  		git_hash_free_ctx(file->digest);
  
  	free(file->buffer);
  
  #ifdef GIT_FILEBUF_THREADS
  	free(file->buffer_back);
  #endif
  
  	free(file->path_original);
  	free(file->path_lock);
  }
  
  static int flush_buffer(git_filebuf *file)
  {
  	int result = GIT_SUCCESS;
  
  	if (file->buf_pos > 0) {
  		result = gitfo_write(file->fd, file->buffer, file->buf_pos);
  		if (file->digest)
  			git_hash_update(file->digest, file->buffer, file->buf_pos);
  
  		file->buf_pos = 0;
  	}
  
  	return result;
  }
  
  int git_filebuf_open(git_filebuf *file, const char *path, int flags)
  {
  	int error;
  	size_t path_len;
  
  	if (file == NULL || path == NULL)
  		return GIT_ERROR;
  
  	memset(file, 0x0, sizeof(git_filebuf));
  
  	file->buf_size = WRITE_BUFFER_SIZE;
  	file->buf_pos = 0;
  	file->fd = -1;
  
  	path_len = strlen(path);
  
  	file->path_original = git__strdup(path);
  	if (file->path_original == NULL) {
  		error = GIT_ENOMEM;
  		goto cleanup;
  	}
  
  	file->path_lock = git__malloc(path_len + GIT_FILELOCK_EXTLENGTH);
  	if (file->path_lock == NULL) {
  		error = GIT_ENOMEM;
  		goto cleanup;
  	}
  
  	memcpy(file->path_lock, file->path_original, path_len);
  	memcpy(file->path_lock + path_len, GIT_FILELOCK_EXTENSION, GIT_FILELOCK_EXTLENGTH);
  
  	file->buffer = git__malloc(file->buf_size);
  	if (file->buffer == NULL){
  		error = GIT_ENOMEM;
  		goto cleanup;
  	}
  
  #ifdef GIT_FILEBUF_THREADS
  	file->buffer_back = git__malloc(file->buf_size);
  	if (file->buffer_back == NULL){
  		error = GIT_ENOMEM;
  		goto cleanup;
  	}
  #endif
  
  	if (flags & GIT_FILEBUF_HASH_CONTENTS) {
  		if ((file->digest = git_hash_new_ctx()) == NULL) {
  			error = GIT_ENOMEM;
  			goto cleanup;
  		}
  	}
  
  	if ((error = lock_file(file, flags)) < GIT_SUCCESS)
  		goto cleanup;
  
  	return GIT_SUCCESS;
  
  cleanup:
  	git_filebuf_cleanup(file);
  	return error;
  }
  
  int git_filebuf_hash(git_oid *oid, git_filebuf *file)
  {
  	int error;
  
  	if (file->digest == NULL)
  		return GIT_ERROR;
  
  	if ((error = flush_buffer(file)) < GIT_SUCCESS)
  		return error;
  
  	git_hash_final(oid, file->digest);
  	git_hash_free_ctx(file->digest);
  	file->digest = NULL;
  
  	return GIT_SUCCESS;
  }
  
  int git_filebuf_commit(git_filebuf *file)
  {
  	int error;
  
  	if ((error = flush_buffer(file)) < GIT_SUCCESS)
  		goto cleanup;
  
  	gitfo_close(file->fd);
  	file->fd = -1;
  
  	error = gitfo_move_file(file->path_lock, file->path_original);
  
  cleanup:
  	git_filebuf_cleanup(file);
  	return error;
  }
  
  GIT_INLINE(void) add_to_cache(git_filebuf *file, void *buf, size_t len)
  {
  	memcpy(file->buffer + file->buf_pos, buf, len);
  	file->buf_pos += len;
  }
  
  int git_filebuf_write(git_filebuf *file, void *buff, size_t len)
  {
  	int error;
  	unsigned char *buf = buff;
  
  	for (;;) {
  		size_t space_left = file->buf_size - file->buf_pos;
  
  		/* cache if it's small */
  		if (space_left > len) {
  			add_to_cache(file, buf, len);
  			return GIT_SUCCESS;
  		}
  
  		/* flush the cache if it doesn't fit */
  		if (file->buf_pos > 0) {
  			add_to_cache(file, buf, space_left);
  
  			if ((error = flush_buffer(file)) < GIT_SUCCESS)
  				return error;
  
  			len -= space_left;
  			buf += space_left;
  		}
  
  		/* write too-large chunks immediately */
  		if (len > file->buf_size) {
  			error = gitfo_write(file->fd, buf, len);
  			if (file->digest)
  				git_hash_update(file->digest, buf, len);
  		}
  	}
  }
  
  int git_filebuf_reserve(git_filebuf *file, void **buffer, size_t len)
  {
  	int error;
  	size_t space_left = file->buf_size - file->buf_pos;
  
  	*buffer = NULL;
  
  	if (len > file->buf_size)
  		return GIT_ENOMEM;
  
  	if (space_left <= len) {
  		if ((error = flush_buffer(file)) < GIT_SUCCESS)
  			return error;
  	}
  
  	*buffer = (file->buffer + file->buf_pos);
  	file->buf_pos += len;
  
  	return GIT_SUCCESS;
  }
  
  int git_filebuf_printf(git_filebuf *file, const char *format, ...)
  {
  	va_list arglist;
  	size_t space_left = file->buf_size - file->buf_pos;
  	int len, error;
  
  	va_start(arglist, format);
  
  	len = vsnprintf((char *)file->buffer + file->buf_pos, space_left, format, arglist);
  
  	if (len < 0 || (size_t)len >= space_left) {
  		if ((error = flush_buffer(file)) < GIT_SUCCESS)
  			return error;
  
  		len = vsnprintf((char *)file->buffer + file->buf_pos, space_left, format, arglist);
  		if (len < 0 || (size_t)len > file->buf_size)
  			return GIT_ENOMEM;
  	}
  
  	file->buf_pos += len;
  	return GIT_SUCCESS;
  
  }
  
  

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