Introduce minikin_stress_tests to find race condition.

This is designed for catching race condition.
The stress_tests is splited from unit test binary since this takes
30 seconds on angler.

Bug: 36223724
Bug: 36208043
Test: ran minikin_stress_tests
Change-Id: I1bf4ba43e6e97cd04e7d6dd42d388dd17ce64c7b

tests/stresstest/Android.mk

+# Copyright (C) 2017 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# see how_to_run.txt for instructions on running these tests
+
+LOCAL_PATH := $(call my-dir)
+
+include $(CLEAR_VARS)
+
+LOCAL_TEST_DATA := $(foreach f,$(LOCAL_TEST_DATA),frameworks/minikin/tests:$(f))
+
+LOCAL_MODULE := minikin_stress_tests
+LOCAL_MODULE_TAGS := tests
+LOCAL_MODULE_CLASS := NATIVE_TESTS
+
+LOCAL_STATIC_LIBRARIES := libminikin
+
+# Shared libraries which are dependencies of minikin; these are not automatically
+# pulled in by the build system (and thus sadly must be repeated).
+
+LOCAL_SHARED_LIBRARIES := \
+    libskia \
+    libft2 \
+    libharfbuzz_ng \
+    libicuuc \
+    liblog \
+    libutils \
+    libz
+
+LOCAL_STATIC_LIBRARIES += \
+    libxml2
+
+LOCAL_SRC_FILES += \
+    ../util/FontTestUtils.cpp \
+    ../util/MinikinFontForTest.cpp \
+    MultithreadTest.cpp \
+
+LOCAL_C_INCLUDES := \
+    $(LOCAL_PATH)/../../libs/minikin/ \
+    $(LOCAL_PATH)/../util \
+    external/libxml2/include \
+
+LOCAL_CPPFLAGS += -Werror -Wall -Wextra
+
+include $(BUILD_NATIVE_TEST)

tests/stresstest/MultithreadTest.cpp

+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <gtest/gtest.h>
+
+#include <condition_variable>
+#include <mutex>
+#include <random>
+#include <thread>
+
+#include <cutils/log.h>
+
+#include "MinikinInternal.h"
+#include "minikin/FontCollection.h"
+#include "minikin/Layout.h"
+#include "../util/FontTestUtils.h"
+
+namespace minikin {
+
+const char* SYSTEM_FONT_PATH = "/system/fonts/";
+const char* SYSTEM_FONT_XML = "/system/etc/fonts.xml";
+
+constexpr int LAYOUT_COUNT_PER_COLLECTION = 500;
+constexpr int COLLECTION_COUNT_PER_THREAD = 15;
+constexpr int NUM_THREADS = 10;
+
+std::mutex gMutex;
+std::condition_variable gCv;
+bool gReady = false;
+
+static std::vector<uint16_t> generateTestText(
+        std::mt19937* mt, int lettersInWord, int wordsInText) {
+    std::uniform_int_distribution<uint16_t> dist('A', 'Z');
+
+    std::vector<uint16_t> text;
+    text.reserve((lettersInWord + 1) * wordsInText - 1);
+    for (int i = 0; i < wordsInText; ++i) {
+        if (i != 0) {
+            text.emplace_back(' ');
+        }
+        for (int j = 0; j < lettersInWord; ++j) {
+            text.emplace_back(dist(*mt));
+        }
+    }
+    return text;
+}
+
+static void thread_main(int tid) {
+    {
+        // Wait until all threads are created.
+        std::unique_lock<std::mutex> lock(gMutex);
+        gCv.wait(lock, [] { return gReady; });
+    }
+
+    std::mt19937 mt(tid);
+    MinikinPaint paint;
+
+    for (int i = 0; i < COLLECTION_COUNT_PER_THREAD; ++i) {
+        std::shared_ptr<FontCollection> collection(
+                getFontCollection(SYSTEM_FONT_PATH, SYSTEM_FONT_XML));
+
+        for (int j = 0; j < LAYOUT_COUNT_PER_COLLECTION; ++j) {
+            // Generates 10 of 3-letter words so that the word sometimes hit the cache.
+            Layout layout;
+            std::vector<uint16_t> text = generateTestText(&mt, 3, 10);
+            layout.doLayout(text.data(), 0, text.size(), text.size(), kBidi_LTR, FontStyle(),
+                    paint, collection);
+            std::vector<float> advances(text.size());
+            layout.getAdvances(advances.data());
+            for (size_t k = 0; k < advances.size(); ++k) {
+                // MinikinFontForTest always returns 10.0f for horizontal advance.
+                LOG_ALWAYS_FATAL_IF(advances[k] != 10.0f, "Memory corruption detected.");
+            }
+        }
+    }
+}
+
+TEST(MultithreadTest, ThreadSafeStressTest) {
+    std::vector<std::thread> threads;
+
+    {
+        std::unique_lock<std::mutex> lock(gMutex);
+        threads.reserve(NUM_THREADS);
+        for (int i = 0; i < NUM_THREADS; ++i) {
+            threads.emplace_back(&thread_main, i);
+        }
+        gReady = true;
+    }
+    gCv.notify_all();
+
+    for (auto& thread : threads) {
+        thread.join();
+    }
+}
+
+}  // namespace minikin

tests/stresstest/how_to_run.txt

+mmm -j8 frameworks/minikin/tests/stresstest &&
+adb sync data &&
+adb shell /data/nativetest/minikin_tests/minikin_stress_tests