thodg/libgit2/src/ident.c

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• Hash : f593fa97
  Author :
  Date : 2021-08-27T16:46:21
  

  ident: use streaming filters

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• src/ident.c

• /*
   * Copyright (C) the libgit2 contributors. All rights reserved.
   *
   * 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 "common.h"
  
  #include "git2/sys/filter.h"
  #include "filter.h"
  #include "buffer.h"
  
  static int ident_find_id(
  	const char **id_start, const char **id_end, const char *start, size_t len)
  {
  	const char *end = start + len, *found = NULL;
  
  	while (len > 3 && (found = memchr(start, '$', len)) != NULL) {
  		size_t remaining = (size_t)(end - found) - 1;
  		if (remaining < 3)
  			return GIT_ENOTFOUND;
  
  		start = found + 1;
  		len   = remaining;
  
  		if (start[0] == 'I' && start[1] == 'd')
  			break;
  	}
  
  	if (len < 3 || !found)
  		return GIT_ENOTFOUND;
  	*id_start = found;
  
  	if ((found = memchr(start + 2, '$', len - 2)) == NULL)
  		return GIT_ENOTFOUND;
  
  	*id_end = found + 1;
  	return 0;
  }
  
  static int ident_insert_id(
  	git_buf *to, const git_buf *from, const git_filter_source *src)
  {
  	char oid[GIT_OID_HEXSZ+1];
  	const char *id_start, *id_end, *from_end = from->ptr + from->size;
  	size_t need_size;
  
  	/* replace $Id$ with blob id */
  
  	if (!git_filter_source_id(src))
  		return GIT_PASSTHROUGH;
  
  	git_oid_tostr(oid, sizeof(oid), git_filter_source_id(src));
  
  	if (ident_find_id(&id_start, &id_end, from->ptr, from->size) < 0)
  		return GIT_PASSTHROUGH;
  
  	need_size = (size_t)(id_start - from->ptr) +
  		5 /* "$Id: " */ + GIT_OID_HEXSZ + 2 /* " $" */ +
  		(size_t)(from_end - id_end);
  
  	if (git_buf_grow(to, need_size) < 0)
  		return -1;
  
  	git_buf_set(to, from->ptr, (size_t)(id_start - from->ptr));
  	git_buf_put(to, "$Id: ", 5);
  	git_buf_put(to, oid, GIT_OID_HEXSZ);
  	git_buf_put(to, " $", 2);
  	git_buf_put(to, id_end, (size_t)(from_end - id_end));
  
  	return git_buf_oom(to) ? -1 : 0;
  }
  
  static int ident_remove_id(
  	git_buf *to, const git_buf *from)
  {
  	const char *id_start, *id_end, *from_end = from->ptr + from->size;
  	size_t need_size;
  
  	if (ident_find_id(&id_start, &id_end, from->ptr, from->size) < 0)
  		return GIT_PASSTHROUGH;
  
  	need_size = (size_t)(id_start - from->ptr) +
  		4 /* "$Id$" */ + (size_t)(from_end - id_end);
  
  	if (git_buf_grow(to, need_size) < 0)
  		return -1;
  
  	git_buf_set(to, from->ptr, (size_t)(id_start - from->ptr));
  	git_buf_put(to, "$Id$", 4);
  	git_buf_put(to, id_end, (size_t)(from_end - id_end));
  
  	return git_buf_oom(to) ? -1 : 0;
  }
  
  static int ident_apply(
  	git_filter     *self,
  	void          **payload,
  	git_buf        *to,
  	const git_buf  *from,
  	const git_filter_source *src)
  {
  	GIT_UNUSED(self); GIT_UNUSED(payload);
  
  	/* Don't filter binary files */
  	if (git_buf_is_binary(from))
  		return GIT_PASSTHROUGH;
  
  	if (git_filter_source_mode(src) == GIT_FILTER_SMUDGE)
  		return ident_insert_id(to, from, src);
  	else
  		return ident_remove_id(to, from);
  }
  
  static int ident_stream(
  	git_writestream **out,
  	git_filter *self,
  	void **payload,
  	const git_filter_source *src,
  	git_writestream *next)
  {
  	return git_filter_buffered_stream_new(out,
  		self, ident_apply, NULL, payload, src, next);
  }
  
  git_filter *git_ident_filter_new(void)
  {
  	git_filter *f = git__calloc(1, sizeof(git_filter));
  	if (f == NULL)
  		return NULL;
  
  	f->version = GIT_FILTER_VERSION;
  	f->attributes = "+ident"; /* apply to files with ident attribute set */
  	f->shutdown = git_filter_free;
  	f->stream   = ident_stream;
  
  	return f;
  }
  

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