Make SkString reference counting thread/TSAN safe.

BUG=skia:7107

Change-Id: I8ead98f7694faaed8e6f6f29b1fcd88501d36b66
Reviewed-on: https://skia-review.googlesource.com/54400
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/tests/StringTest.cpp b/tests/StringTest.cpp
index 8ae7412187..91ef009edd 100644
--- a/tests/StringTest.cpp
+++ b/tests/StringTest.cpp
@@ -8,6 +8,7 @@
 #include <stdarg.h>
 #include <stdio.h>
 #include "SkString.h"
+#include "SkThreadUtils.h"
 #include "Test.h"
 
 // Windows vsnprintf doesn't 0-terminate safely), but is so far
@@ -287,3 +288,26 @@ DEF_TEST(String_SkStrSplit_All, r) {
     REPORTER_ASSERT(r, results[2].equals("b"));
     REPORTER_ASSERT(r, results[3].equals(""));
 }
+
+// https://bugs.chromium.org/p/skia/issues/detail?id=7107
+DEF_TEST(String_Threaded, r) {
+    SkString gString("foo");
+    SkThread::entryPointProc readString = [](void* context) -> void {
+        SkString gStringCopy = *reinterpret_cast<SkString*>(context);
+        bool equals_string = gStringCopy.equals("test");
+        (void)equals_string;
+    };
+    SkThread threads[] = {
+        {readString, &gString},
+        {readString, &gString},
+        {readString, &gString},
+        {readString, &gString},
+        {readString, &gString},
+    };
+    for (SkThread& thread : threads) {
+        thread.start();
+    }
+    for (SkThread& thread : threads) {
+        thread.join();
+    }
+}