thodg/libgit2/src/parse.c

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• Hash : ef1395f3
  Author :
  Date : 2017-11-11T15:30:43
  

  parse: extract parse module
  
  The `git_patch_parse_ctx` encapsulates both parser state as well as
  options specific to patch parsing. To advance this state and keep it
  consistent, we provide a few functions which handle advancing the
  current position and accessing bytes of the patch contents. In fact,
  these functions are quite generic and not related to patch-parsing by
  themselves. Seeing that we have similar logic inside of other modules,
  it becomes quite enticing to extract this functionality into its own
  parser module.
  
  To do so, we create a new module `parse` with a central struct called
  `git_parse_ctx`. It encapsulates both the content that is to be parsed
  as well as its lengths and the current position. `git_patch_parse_ctx`
  now only contains this `parse_ctx` only, which is then accessed whenever
  we need to touch the current parser. This is the first step towards
  re-using this functionality across other modules which require parsing
  functionality and remove code-duplication.
  

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• src/parse.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 "parse.h"
  
  int git_parse_ctx_init(git_parse_ctx *ctx, const char *content, size_t content_len)
  {
  	if (content_len)
  		ctx->content = content;
  	else
  		ctx->content = NULL;
  
  	ctx->content_len = content_len;
  	ctx->remain = ctx->content;
  	ctx->remain_len = ctx->content_len;
  
  	return 0;
  }
  
  void git_parse_ctx_clear(git_parse_ctx *ctx)
  {
  	memset(ctx, 0, sizeof(*ctx));
  }
  
  void git_parse_advance_line(git_parse_ctx *ctx)
  {
  	ctx->line += ctx->line_len;
  	ctx->remain_len -= ctx->line_len;
  	ctx->line_len = git__linenlen(ctx->line, ctx->remain_len);
  	ctx->line_num++;
  }
  
  void git_parse_advance_chars(git_parse_ctx *ctx, size_t char_cnt)
  {
  	ctx->line += char_cnt;
  	ctx->remain_len -= char_cnt;
  	ctx->line_len -= char_cnt;
  }
  
  int git_parse_advance_expected(
  	git_parse_ctx *ctx,
  	const char *expected,
  	size_t expected_len)
  {
  	if (ctx->line_len < expected_len)
  		return -1;
  
  	if (memcmp(ctx->line, expected, expected_len) != 0)
  		return -1;
  
  	git_parse_advance_chars(ctx, expected_len);
  	return 0;
  }
  
  int git_parse_advance_ws(git_parse_ctx *ctx)
  {
  	int ret = -1;
  
  	while (ctx->line_len > 0 &&
  		ctx->line[0] != '\n' &&
  		git__isspace(ctx->line[0])) {
  		ctx->line++;
  		ctx->line_len--;
  		ctx->remain_len--;
  		ret = 0;
  	}
  
  	return ret;
  }
  
  int git_parse_advance_nl(git_parse_ctx *ctx)
  {
  	if (ctx->line_len != 1 || ctx->line[0] != '\n')
  		return -1;
  
  	git_parse_advance_line(ctx);
  	return 0;
  }
  

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