thodg/libgit2/tests/str/oom.c

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• Hash : f0e693b1
  Author :
  Date : 2021-09-07T17:53:49
  

  str: introduce `git_str` for internal, `git_buf` is external libgit2 has two distinct requirements that were previously solved by `git_buf`. We require: 1. A general purpose string class that provides a number of utility APIs for manipulating data (eg, concatenating, truncating, etc). 2. A structure that we can use to return strings to callers that they can take ownership of. By using a single class (`git_buf`) for both of these purposes, we have confused the API to the point that refactorings are difficult and reasoning about correctness is also difficult. Move the utility class `git_buf` to be called `git_str`: this represents its general purpose, as an internal string buffer class. The name also is an homage to Junio Hamano ("gitstr"). The public API remains `git_buf`, and has a much smaller footprint. It is generally only used as an "out" param with strict requirements that follow the documentation. (Exceptions exist for some legacy APIs to avoid breaking callers unnecessarily.) Utility functions exist to convert a user-specified `git_buf` to a `git_str` so that we can call internal functions, then converting it back again.

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• tests/str/oom.c

• #include "clar_libgit2.h"
  
  /* Override default allocators with ones that will fail predictably. */
  
  static git_allocator std_alloc;
  static git_allocator oom_alloc;
  
  static void *oom_malloc(size_t n, const char *file, int line)
  {
  	/* Reject any allocation of more than 100 bytes */
  	return (n > 100) ? NULL : std_alloc.gmalloc(n, file, line);
  }
  
  static void *oom_realloc(void *p, size_t n, const char *file, int line)
  {
  	/* Reject any allocation of more than 100 bytes */
  	return (n > 100) ? NULL : std_alloc.grealloc(p, n, file, line);
  }
  
  void test_str_oom__initialize(void)
  {
  	git_stdalloc_init_allocator(&std_alloc);
  	git_stdalloc_init_allocator(&oom_alloc);
  
  	oom_alloc.gmalloc = oom_malloc;
  	oom_alloc.grealloc = oom_realloc;
  
  	cl_git_pass(git_libgit2_opts(GIT_OPT_SET_ALLOCATOR, &oom_alloc));
  }
  
  void test_str_oom__cleanup(void)
  {
  	cl_git_pass(git_libgit2_opts(GIT_OPT_SET_ALLOCATOR, NULL));
  }
  
  void test_str_oom__grow(void)
  {
  	git_str buf = GIT_STR_INIT;
  
  	cl_git_pass(git_str_grow(&buf, 42));
  	cl_assert(!git_str_oom(&buf));
  
  	cl_assert(git_str_grow(&buf, 101) == -1);
  	cl_assert(git_str_oom(&buf));
  
  	git_str_dispose(&buf);
  }
  
  void test_str_oom__grow_by(void)
  {
  	git_str buf = GIT_STR_INIT;
  
  	cl_git_pass(git_str_grow_by(&buf, 42));
  	cl_assert(!git_str_oom(&buf));
  
  	cl_assert(git_str_grow_by(&buf, 101) == -1);
  	cl_assert(git_str_oom(&buf));
  }
  

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