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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