thodg/libgit2/src/hash/hash_common_crypto.h

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• Hash : 03dc6480
  Author :
  Date : 2019-01-02T09:27:44
  

  hash: convert `global_init` macros to real function The `git_hash_global_init` function is simply defined as a macro to zero for most of the different hash implementations. This makes it impossible to treat it like a function pointer, which is required for a later commit where we want to improve the way global initialization works. Fix the issue by converting all no-op macros to an inline function returning zero. There's a small gotcha here, though: as most hash implementations only have a header file, but not a corresponding implementation file, we cannot declare the function as non-static. But declaring it as `static inline` fails, too, as there is a previous declaration as non-static. So we have to move the function declaration after the include that brings in the function definition, as it is allowed to have a non-static declaration after a static definition, but not the other way round.

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• src/hash/hash_common_crypto.h

• /*
   * 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.
   */
  
  #ifndef INCLUDE_hash_hash_common_crypto_h__
  #define INCLUDE_hash_hash_common_crypto_h__
  
  #include "hash.h"
  
  #include <CommonCrypto/CommonDigest.h>
  
  struct git_hash_ctx {
  	CC_SHA1_CTX c;
  };
  
  #define CC_LONG_MAX ((CC_LONG)-1)
  
  #define git_hash_ctx_init(ctx) git_hash_init(ctx)
  #define git_hash_ctx_cleanup(ctx)
  
  GIT_INLINE(int) git_hash_global_init(void)
  {
  	return 0;
  }
  
  GIT_INLINE(int) git_hash_init(git_hash_ctx *ctx)
  {
  	assert(ctx);
  	CC_SHA1_Init(&ctx->c);
  	return 0;
  }
  
  GIT_INLINE(int) git_hash_update(git_hash_ctx *ctx, const void *_data, size_t len)
  {
  	const unsigned char *data = _data;
  
  	assert(ctx);
  
  	while (len > 0) {
  		CC_LONG chunk = (len > CC_LONG_MAX) ? CC_LONG_MAX : (CC_LONG)len;
  
  		CC_SHA1_Update(&ctx->c, data, chunk);
  
  		data += chunk;
  		len -= chunk;
  	}
  
  	return 0;
  }
  
  GIT_INLINE(int) git_hash_final(git_oid *out, git_hash_ctx *ctx)
  {
  	assert(ctx);
  	CC_SHA1_Final(out->id, &ctx->c);
  	return 0;
  }
  
  #endif
  

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