Implements a simple regex matcher (to be used by death tests on Windows).

include/gtest/gtest-death-test.h

@@ -86,6 +86,57 @@ GTEST_DECLARE_string_(death_test_style);
 //
 //   ASSERT_EXIT(client.HangUpServer(), KilledBySIGHUP, "Hanging up!");
 //
+// On the regular expressions used in death tests:
+//
+//   On POSIX-compliant systems (*nix), we use the <regex.h> library,
+//   which uses the POSIX extended regex syntax.
+//
+//   On other platforms (e.g. Windows), we only support a simple regex
+//   syntax implemented as part of Google Test.  This limited
+//   implementation should be enough most of the time when writing
+//   death tests; though it lacks many features you can find in PCRE
+//   or POSIX extended regex syntax.  For example, we don't support
+//   union ("x|y"), grouping ("(xy)"), brackets ("[xy]"), and
+//   repetition count ("x{5,7}"), among others.
+//
+//   Below is the syntax that we do support.  We chose it to be a
+//   subset of both PCRE and POSIX extended regex, so it's easy to
+//   learn wherever you come from.  In the following: 'A' denotes a
+//   literal character, period (.), or a single \\ escape sequence;
+//   'x' and 'y' denote regular expressions; 'm' and 'n' are for
+//   natural numbers.
+//
+//     c     matches any literal character c
+//     \\d   matches any decimal digit
+//     \\D   matches any character that's not a decimal digit
+//     \\f   matches \f
+//     \\n   matches \n
+//     \\r   matches \r
+//     \\s   matches any ASCII whitespace, including \n
+//     \\S   matches any character that's not a whitespace
+//     \\t   matches \t
+//     \\v   matches \v
+//     \\w   matches any letter, _, or decimal digit
+//     \\W   matches any character that \\w doesn't match
+//     \\c   matches any literal character c, which must be a punctuation
+//     .     matches any single character except \n
+//     A?    matches 0 or 1 occurrences of A
+//     A*    matches 0 or many occurrences of A
+//     A+    matches 1 or many occurrences of A
+//     ^     matches the beginning of a string (not that of each line)
+//     $     matches the end of a string (not that of each line)
+//     xy    matches x followed by y
+//
+//   If you accidentally use PCRE or POSIX extended regex features
+//   not implemented by us, you will get a run-time failure.  In that
+//   case, please try to rewrite your regular expression within the
+//   above syntax.
+//
+//   This implementation is *not* meant to be as highly tuned or robust
+//   as a compiled regex library, but should perform well enough for a
+//   death test, which already incurs significant overhead by launching
+//   a child process.
+//
 // Known caveats:
 //
 //   A "threadsafe" style death test obtains the path to the test

include/gtest/internal/gtest-port.h

@@ -97,6 +97,9 @@
 //   GTEST_HAS_TYPED_TEST   - defined iff typed tests are supported.
 //   GTEST_HAS_TYPED_TEST_P - defined iff type-parameterized tests are
 //                            supported.
+//   GTEST_USES_POSIX_RE    - defined iff enhanced POSIX regex is used.
+//   GTEST_USES_SIMPLE_RE   - defined iff our own simple regex is used;
+//                            the above two are mutually exclusive.
 //
 // Macros for basic C++ coding:
 //   GTEST_AMBIGUOUS_ELSE_BLOCKER_ - for disabling a gcc warning.
@@ -187,6 +190,23 @@
 #define GTEST_OS_SOLARIS
 #endif  // _MSC_VER
 
+#if defined(GTEST_OS_LINUX)
+
+// On some platforms, <regex.h> needs someone to define size_t, and
+// won't compile otherwise.  We can #include it here as we already
+// included <stdlib.h>, which is guaranteed to define size_t through
+// <stddef.h>.
+#include <regex.h>  // NOLINT
+#define GTEST_USES_POSIX_RE 1
+
+#else
+
+// We are not on Linux, so <regex.h> may not be available.  Use our
+// own simple regex implementation instead.
+#define GTEST_USES_SIMPLE_RE 1
+
+#endif  // GTEST_OS_LINUX
+
 // Determines whether ::std::string and ::string are available.
 
 #ifndef GTEST_HAS_STD_STRING
@@ -352,11 +372,6 @@
 // Determines whether to support death tests.
 #if GTEST_HAS_STD_STRING && GTEST_HAS_CLONE
 #define GTEST_HAS_DEATH_TEST
-// On some platforms, <regex.h> needs someone to define size_t, and
-// won't compile otherwise.  We can #include it here as we already
-// included <stdlib.h>, which is guaranteed to define size_t through
-// <stddef.h>.
-#include <regex.h>
 #include <vector>
 #include <fcntl.h>
 #include <sys/mman.h>
@@ -375,8 +390,8 @@
 // Typed tests need <typeinfo> and variadic macros, which gcc and VC
 // 8.0+ support.
 #if defined(__GNUC__) || (_MSC_VER >= 1400)
-#define GTEST_HAS_TYPED_TEST
-#define GTEST_HAS_TYPED_TEST_P
+#define GTEST_HAS_TYPED_TEST 1
+#define GTEST_HAS_TYPED_TEST_P 1
 #endif  // defined(__GNUC__) || (_MSC_VER >= 1400)
 
 // Determines whether to support Combine(). This only makes sense when
@@ -490,8 +505,6 @@ class scoped_ptr {
   GTEST_DISALLOW_COPY_AND_ASSIGN_(scoped_ptr);
 };
 
-#ifdef GTEST_HAS_DEATH_TEST
-
 // Defines RE.
 
 // A simple C++ wrapper for <regex.h>.  It uses the POSIX Enxtended
@@ -549,12 +562,16 @@ class RE {
   // String type here, in order to simplify dependencies between the
   // files.
   const char* pattern_;
+  bool is_valid_;
+#if GTEST_USES_POSIX_RE
   regex_t full_regex_;     // For FullMatch().
   regex_t partial_regex_;  // For PartialMatch().
-  bool is_valid_;
-};
+#else  // GTEST_USES_SIMPLE_RE
+  const char* full_pattern_;  // For FullMatch();
+#endif
 
-#endif  // GTEST_HAS_DEATH_TEST
+  GTEST_DISALLOW_COPY_AND_ASSIGN_(RE);
+};
 
 // Defines logging utilities:
 //   GTEST_LOG_()   - logs messages at the specified severity level.