aaudio: keep track of streams using strong pointers

Maintain strong pointer to service stream during service calls.
Use simple AAudioStreamTracker instead of complex HandleTracker.

Bug: 65280854
Test: affects all MMAP streams, run all CTS tests, etcetera
Change-Id: I3d2ed8b588ea39c216dacd4dea503b11c33f36f3
diff --git a/services/oboeservice/AAudioStreamTracker.cpp b/services/oboeservice/AAudioStreamTracker.cpp
new file mode 100644
index 0000000..ef88b34
--- /dev/null
+++ b/services/oboeservice/AAudioStreamTracker.cpp
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#define LOG_TAG "AAudioStreamTracker"
+//#define LOG_NDEBUG 0
+#include <utils/Log.h>
+
+#include <iomanip>
+#include <iostream>
+#include <sstream>
+
+#include <aaudio/AAudio.h>
+#include <utils/String16.h>
+
+#include "AAudioStreamTracker.h"
+
+using namespace android;
+using namespace aaudio;
+
+sp<AAudioServiceStreamBase> AAudioStreamTracker::removeStreamByHandle(
+        aaudio_handle_t streamHandle) {
+    std::lock_guard<std::mutex> lock(mHandleLock);
+    sp<AAudioServiceStreamBase> serviceStream;
+    auto it = mStreamsByHandle.find(streamHandle);
+    if (it != mStreamsByHandle.end()) {
+        serviceStream = it->second;
+        mStreamsByHandle.erase(it);
+    }
+    return serviceStream;
+}
+
+sp<AAudioServiceStreamBase> AAudioStreamTracker::getStreamByHandle(
+        aaudio_handle_t streamHandle) {
+    std::lock_guard<std::mutex> lock(mHandleLock);
+    sp<AAudioServiceStreamBase> serviceStream;
+    auto it = mStreamsByHandle.find(streamHandle);
+    if (it != mStreamsByHandle.end()) {
+        serviceStream = it->second;
+    }
+    return serviceStream;
+}
+
+// advance to next legal handle value
+__attribute__((no_sanitize("integer")))
+aaudio_handle_t AAudioStreamTracker::bumpHandle(aaudio_handle_t handle) {
+    handle++;
+    // Only use positive integers.
+    if (handle <= 0) {
+        handle = 1;
+    }
+    return handle;
+}
+
+aaudio_handle_t AAudioStreamTracker::addStreamForHandle(sp<AAudioServiceStreamBase> serviceStream) {
+    std::lock_guard<std::mutex> lock(mHandleLock);
+    aaudio_handle_t handle = mPreviousHandle.load();
+    // Assign a unique handle.
+    while (true) {
+        handle = bumpHandle(handle);
+        sp<AAudioServiceStreamBase> oldServiceStream = mStreamsByHandle[handle];
+        // Is this an unused handle? It would be extremely unlikely to wrap
+        // around and collide with a very old handle. But just in case.
+        if (oldServiceStream.get() == nullptr) {
+            mStreamsByHandle[handle] = serviceStream;
+            break;
+        }
+    }
+    mPreviousHandle.store(handle);
+    return handle;
+}
+
+std::string AAudioStreamTracker::dump() const {
+    std::stringstream result;
+    const bool isLocked = AAudio_tryUntilTrue(
+            [this]()->bool { return mHandleLock.try_lock(); } /* f */,
+            50 /* times */,
+            20 /* sleepMs */);
+    if (!isLocked) {
+        result << "AAudioStreamTracker may be deadlocked\n";
+    } else {
+        result << "Stream Handles:\n";
+        for (const auto&  it : mStreamsByHandle) {
+            aaudio_handle_t handle = it.second->getHandle();
+            result << "    0x" << std::setfill('0') << std::setw(8) << std::hex << handle
+                   << std::dec << std::setfill(' ') << "\n";
+        }
+
+        mHandleLock.unlock();
+    }
+    return result.str();
+}