breakpad/src/common/tests/auto_testfile.h

// Copyright (c) 2013, Google Inc.
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// modification, are permitted provided that the following conditions are
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// Utility class for creating a temporary file for unit tests
// that is deleted in the destructor. Only supported on Posix systems.
#ifndef GOOGLE_BREAKPAD_COMMON_TESTS_AUTO_TESTFILE
#define GOOGLE_BREAKPAD_COMMON_TESTS_AUTO_TESTFILE

#include <unistd.h>
#include <sys/types.h>
#include <string>

#include "breakpad_googletest_includes.h"
#include "common/tests/auto_tempdir.h"

namespace google_breakpad {

#ifdef _WIN32
#error "This header cannot be used on Windows"
#else

class AutoTestFile {
public:
  // Create a new empty test file.
  // test_prefix: (input) test-specific prefix, can't be NULL.
  explicit AutoTestFile(const char* test_prefix) {
    Init(test_prefix);
  }

  // Create a new test file, and fill it with initial data from a C string.
  // The terminating zero is not written.
  // test_prefix: (input) test-specific prefix, can't be NULL.
  // text: (input) initial content.
  AutoTestFile(const char* test_prefix, const char* text) {
    Init(test_prefix);
    if (fd_ >= 0)
      WriteText(text, static_cast<size_t>(strlen(text)));
  }

  AutoTestFile(const char* test_prefix, const char* text, size_t text_len) {
    Init(test_prefix);
    if (fd_ >= 0)
      WriteText(text, text_len);
  }

  // Destroy test file on scope exit.
  ~AutoTestFile() {
    if (fd_ >= 0) {
      close(fd_);
      fd_ = -1;
    }
  }

  // Returns true iff the test file could be created properly.
  // Useful in tests inside EXPECT_TRUE(file.IsOk());
  bool IsOk() {
    return fd_ >= 0;
  }

  // Returns the Posix file descriptor for the test file, or -1
  // If IsOk() returns false. Note: on Windows, this always returns -1.
  int GetFd() {
    return fd_;
  }

private:
  void Init(const char* test_prefix) {
    fd_ = -1;
    char path_templ[PATH_MAX];
    int ret = snprintf(path_templ, sizeof(path_templ),
                      TEMPDIR "/%s-unittest.XXXXXX",
                      test_prefix);
    if (ret >= static_cast<int>(sizeof(path_templ)))
      return;

    fd_ = mkstemp(path_templ);
    if (fd_ < 0)
      return;

    unlink(path_templ);
  }

  void WriteText(const char* text, size_t text_len) {
    int r = HANDLE_EINTR(write(fd_, text, text_len));
    if (r != static_cast<int>(text_len)) {
      close(fd_);
      fd_ = -1;
      return;
    }

    lseek(fd_, 0, SEEK_SET);
  }

  int fd_;
};

#endif  // !_WIN32

}  // namespace google_breakpad

#endif  // GOOGLE_BREAKPAD_COMMON_TESTS_AUTO_TESTFILE