diff -r 000000000000 -r 6474c204b198 xpcom/tests/TestThreads.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/tests/TestThreads.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,223 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsThreadUtils.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include "nspr.h"
+#include "nsCOMPtr.h"
+#include "nsIServiceManager.h"
+#include "nsXPCOM.h"
+
+class nsRunner : public nsIRunnable {
+public:
+    NS_DECL_THREADSAFE_ISUPPORTS
+
+    NS_IMETHOD Run() {
+        nsCOMPtr<nsIThread> thread;
+        nsresult rv = NS_GetCurrentThread(getter_AddRefs(thread));
+        if (NS_FAILED(rv)) {
+            printf("failed to get current thread\n");
+            return rv;
+        }
+        printf("running %d on thread %p\n", mNum, (void *)thread.get());
+
+        // if we don't do something slow, we'll never see the other
+        // worker threads run
+        PR_Sleep(PR_MillisecondsToInterval(100));
+
+        return rv;
+    }
+
+    nsRunner(int num) : mNum(num) {
+    }
+
+protected:
+    int mNum;
+};
+
+NS_IMPL_ISUPPORTS(nsRunner, nsIRunnable)
+
+nsresult
+TestThreads()
+{
+    nsresult rv;
+
+    nsCOMPtr<nsIRunnable> event = new nsRunner(0);
+    if (!event)
+        return NS_ERROR_OUT_OF_MEMORY;
+
+    nsCOMPtr<nsIThread> runner;
+    rv = NS_NewThread(getter_AddRefs(runner), event);
+    if (NS_FAILED(rv)) {
+        printf("failed to create thread\n");
+        return rv;
+    }
+
+    nsCOMPtr<nsIThread> thread;
+    rv = NS_GetCurrentThread(getter_AddRefs(thread));
+    if (NS_FAILED(rv)) {
+        printf("failed to get current thread\n");
+        return rv;
+    }
+
+    rv = runner->Shutdown();     // wait for the runner to die before quitting
+    if (NS_FAILED(rv)) {
+        printf("join failed\n");        
+    }
+
+    PR_Sleep(PR_MillisecondsToInterval(100));       // hopefully the runner will quit here
+
+    return NS_OK;
+}
+
+class nsStressRunner : public nsIRunnable {
+public:
+    NS_DECL_THREADSAFE_ISUPPORTS
+
+    NS_IMETHOD Run() {
+        NS_ASSERTION(!mWasRun, "run twice!");
+        mWasRun = true;
+        PR_Sleep(1);
+        if (!PR_AtomicDecrement(&gNum)) {
+            printf("   last thread was %d\n", mNum);
+        }
+        return NS_OK;
+    }
+
+    nsStressRunner(int num) : mNum(num), mWasRun(false) {
+        PR_AtomicIncrement(&gNum);
+    }
+
+    static int32_t GetGlobalCount() {return gNum;}
+
+private:
+    ~nsStressRunner() {
+        NS_ASSERTION(mWasRun, "never run!");
+    }
+
+protected:
+    static int32_t gNum;
+    int32_t mNum;
+    bool mWasRun;
+};
+
+int32_t nsStressRunner::gNum = 0;
+
+NS_IMPL_ISUPPORTS(nsStressRunner, nsIRunnable)
+
+static int Stress(int loops, int threads)
+{
+
+    for (int i = 0; i < loops; i++) {
+        printf("Loop %d of %d\n", i+1, loops);
+
+        int k;
+        nsIThread** array = new nsIThread*[threads];
+        NS_ASSERTION(array, "out of memory");
+
+        NS_ASSERTION(!nsStressRunner::GetGlobalCount(), "bad count of runnables");
+        
+        for (k = 0; k < threads; k++) {
+            nsCOMPtr<nsIThread> t;
+            nsresult rv = NS_NewThread(getter_AddRefs(t), new nsStressRunner(k));
+            if (NS_FAILED(rv)) {
+                NS_ERROR("can't create thread");
+                return -1;
+            }
+            NS_ADDREF(array[k] = t);
+        }
+
+        for (k = threads-1; k >= 0; k--) {
+            array[k]->Shutdown();
+            NS_RELEASE(array[k]);    
+        }
+        delete [] array;
+    }
+    return 0;
+}
+
+static void threadProc(void *arg)
+{
+    // printf("   running thread %d\n", (int) arg);
+    PR_Sleep(1);
+    PR_ASSERT(PR_JOINABLE_THREAD == PR_GetThreadState(PR_GetCurrentThread()));
+}
+
+static int StressNSPR(int loops, int threads)
+{
+
+    for (int i = 0; i < loops; i++) {
+        printf("Loop %d of %d\n", i+1, loops);
+
+        int k;
+        PRThread** array = new PRThread*[threads];
+        PR_ASSERT(array);
+
+        for (k = 0; k < threads; k++) {
+            array[k] = PR_CreateThread(PR_USER_THREAD,
+                                       threadProc, (void*) k,
+                                       PR_PRIORITY_NORMAL,
+                                       PR_GLOBAL_THREAD,
+                                       PR_JOINABLE_THREAD,
+                                       0);
+            PR_ASSERT(array[k]);
+        }                               
+
+        for (k = 0; k < threads; k++) {
+            PR_ASSERT(PR_JOINABLE_THREAD == PR_GetThreadState(array[k]));
+        }                               
+
+        for (k = threads-1; k >= 0; k--) {
+            PR_JoinThread(array[k]);
+        }
+        delete [] array;
+    }
+    return 0;
+}
+
+
+int
+main(int argc, char** argv)
+{
+    int retval = 0;
+    nsresult rv;
+    
+    rv = NS_InitXPCOM2(nullptr, nullptr, nullptr);
+    if (NS_FAILED(rv)) return -1;
+
+    if (argc > 1 && !strcmp(argv[1], "-stress")) {
+        int loops;
+        int threads;
+        if (argc != 4 || *argv[2] != '-' || *argv[3] != '-' ||
+            !(loops = atoi(argv[2]+1)) || !(threads = atoi(argv[3]+1))) {
+           printf("To use -stress you must pass loop count and thread count...\n"
+                  "   TestThreads -stress -1000 -50\n");
+        } else {
+           printf("Running stress test with %d loops of %d threads each\n",
+                  loops, threads);
+           retval = Stress(loops, threads);
+        }
+    } else if (argc > 1 && !strcmp(argv[1], "-stress-nspr")) {
+        int loops;
+        int threads;
+        if (argc != 4 || *argv[2] != '-' || *argv[3] != '-' ||
+            !(loops = atoi(argv[2]+1)) || !(threads = atoi(argv[3]+1))) {
+           printf("To use -stress-nspr you must pass loop count and thread count...\n"
+                  "   TestThreads -stress -1000 -50\n");
+        } else {
+           printf("Running stress test with %d loops of %d threads each\n",
+                  loops, threads);
+           retval = StressNSPR(loops, threads);
+        }
+    } else {
+        rv = TestThreads();
+        if (NS_FAILED(rv)) return -1;
+    }
+
+    rv = NS_ShutdownXPCOM(nullptr);
+    if (NS_FAILED(rv)) return -1;
+    return retval;
+}