android/android-emu/android/base/synchronization/MessageChannel_unittest.cpp

// Copyright 2014 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 "android/base/synchronization/MessageChannel.h"

#include "android/base/testing/TestThread.h"

#include <gtest/gtest.h>

#include <memory>
#include <string>

namespace android {
namespace base {

namespace {

struct PingPongState {
    MessageChannel<std::string, 3U> in;
    MessageChannel<std::string, 3U> out;
};

void* pingPongFunction(void* param) {
    for (;;) {
        PingPongState* s = static_cast<PingPongState*>(param);
        std::string str;
        s->in.receive(&str);
        if (s->in.isStopped()) {
            return (void*)-1;
        }
        s->out.send(str);
        if (s->out.isStopped()) {
            return (void*)-1;
        }
        if (str == "quit") {
            return 0;
        }
    }
}

}  // namespace

TEST(MessageChannel, SingleThreadWithInt) {
    MessageChannel<int, 3U> channel;
    channel.send(1);
    channel.send(2);
    channel.send(3);

    int ret;
    channel.receive(&ret);
    EXPECT_EQ(1, ret);
    channel.receive(&ret);
    EXPECT_EQ(2, ret);
    channel.receive(&ret);
    EXPECT_EQ(3, ret);
}

TEST(MessageChannel, SingleThreadWithStdString) {
    MessageChannel<std::string, 5U> channel;
    channel.send(std::string("foo"));
    channel.send(std::string("bar"));
    channel.send(std::string("zoo"));

    std::string str;
    channel.receive(&str);
    EXPECT_STREQ("foo", str.c_str());
    channel.receive(&str);
    EXPECT_STREQ("bar", str.c_str());
    channel.receive(&str);
    EXPECT_STREQ("zoo", str.c_str());
}

TEST(MessageChannel, TwoThreadsPingPong) {
    PingPongState state;
    auto thread = std::unique_ptr<TestThread>(
            new TestThread(pingPongFunction, &state));

    std::string str;
    const size_t kCount = 100;
    for (size_t n = 0; n < kCount; ++n) {
        state.in.send(std::string("foo"));
        state.in.send(std::string("bar"));
        state.in.send(std::string("zoo"));
        state.out.receive(&str);
        EXPECT_STREQ("foo", str.c_str());
        state.out.receive(&str);
        EXPECT_STREQ("bar", str.c_str());
        state.out.receive(&str);
        EXPECT_STREQ("zoo", str.c_str());
    }
    state.in.send(std::string("quit"));
    state.out.receive(&str);
    EXPECT_STREQ("quit", str.c_str());

    thread->join();
}

TEST(MessageChannel, Stop) {
    {
        PingPongState state;
        auto thread = std::unique_ptr<TestThread>(
                new TestThread(pingPongFunction, &state));

        // the thread has to be blocked on in.receive(), let's stop it
        state.in.stop();
        EXPECT_NE(0, thread->join());
        EXPECT_EQ(android::base::kNullopt, state.in.receive());
        state.in.send("1");
        EXPECT_EQ(0, state.in.size());
    }

    {
        PingPongState state;
        auto thread = std::unique_ptr<TestThread>(
                new TestThread(pingPongFunction, &state));

        // fill in the receiving message channel
        while (state.out.size() < state.out.capacity()) {
            state.in.send("1");
        }

        // not the thread is blocked on out.send()
        state.out.stop();

        EXPECT_NE(0, thread->join());
    }
}

TEST(MessageChannel, TryVersions) {
    MessageChannel<int, 2> channel;
    int ret;
    EXPECT_FALSE(channel.tryReceive(&ret));

    EXPECT_TRUE(channel.trySend(1));
    EXPECT_TRUE(channel.trySend(2));
    EXPECT_FALSE(channel.trySend(3));

    EXPECT_TRUE(channel.tryReceive(&ret));
    EXPECT_EQ(1, ret);
    EXPECT_TRUE(channel.tryReceive(&ret));
    EXPECT_EQ(2, ret);
    EXPECT_FALSE(channel.tryReceive(&ret));
    // make sure |ret| wasn't changed
    EXPECT_EQ(2, ret);
}

}  // namespace base
}  // namespace android