[dart:io] Adds Platform.operatingSystemVersion

runtime/bin/platform_macos.cc

Index: runtime/bin/platform_macos.cc
diff --git a/runtime/bin/platform_macos.cc b/runtime/bin/platform_macos.cc
index b02bca7554f31e8de0237fd29de4f9a8f97a0815..e563788ceb3e22cab73e623d54dbbd4c08b72ac2 100644
--- a/runtime/bin/platform_macos.cc
+++ b/runtime/bin/platform_macos.cc
@@ -13,11 +13,12 @@
 #include <crt_externs.h>  // NOLINT
 #endif                    // !HOST_OS_IOS
 #include <mach-o/dyld.h>
-#include <signal.h>      // NOLINT
-#include <string.h>      // NOLINT
-#include <sys/sysctl.h>  // NOLINT
-#include <sys/types.h>   // NOLINT
-#include <unistd.h>      // NOLINT
+#include <signal.h>       // NOLINT
+#include <string.h>       // NOLINT
+#include <sys/sysctl.h>   // NOLINT
+#include <sys/types.h>    // NOLINT
+#include <sys/utsname.h>  // NOLINT
+#include <unistd.h>       // NOLINT
 
 #include "bin/fdutils.h"
 #include "bin/file.h"
@@ -90,6 +91,28 @@ const char* Platform::OperatingSystem() {
 #endif
 }
 
+const char* Platform::OperatingSystemVersion() {
+  struct utsname info;
+  int ret = uname(&info);
+  if (ret != 0) {
+    return NULL;
+  }
+  const char* kFormat = "%s %s %s";
+  int len =
+      snprintf(NULL, 0, kFormat, info.sysname, info.release, info.version);
+  if (len <= 0) {
+    return NULL;
+  }
+  char* result = DartUtils::ScopedCString(len + 1);
+  ASSERT(result != NULL);
+  len = snprintf(result, len + 1, kFormat, info.sysname, info.release,
+                 info.version);
+  if (len <= 0) {
+    return NULL;
+  }
+  return result;
+}
+
 const char* Platform::LibraryPrefix() {
   return "lib";
 }