Use RAII for locking/unlocking buffers.

Bug: 324383963
Test: atest virtual_camera_tests
Test: atest VirtualCameraTest

Change-Id: I8d8071250f7847334a75e261c7f69b5022e04507
diff --git a/services/camera/virtualcamera/util/Util.cc b/services/camera/virtualcamera/util/Util.cc
index ef986a6..b2048bc 100644
--- a/services/camera/virtualcamera/util/Util.cc
+++ b/services/camera/virtualcamera/util/Util.cc
@@ -20,8 +20,13 @@
 
 #include <algorithm>
 #include <array>
+#include <cstdint>
+#include <memory>
 
+#include "android/hardware_buffer.h"
 #include "jpeglib.h"
+#include "ui/GraphicBuffer.h"
+#include "utils/Errors.h"
 
 namespace android {
 namespace companion {
@@ -40,6 +45,82 @@
 constexpr std::array<Format, 2> kSupportedFormats{Format::YUV_420_888,
                                                   Format::RGBA_8888};
 
+YCbCrLockGuard::YCbCrLockGuard(std::shared_ptr<AHardwareBuffer> hwBuffer,
+                               const uint32_t usageFlags)
+    : mHwBuffer(hwBuffer) {
+  GraphicBuffer* gBuffer = GraphicBuffer::fromAHardwareBuffer(mHwBuffer.get());
+  if (gBuffer == nullptr) {
+    ALOGE("%s: Attempting to lock nullptr buffer.", __func__);
+    return;
+  }
+  mLockStatus = gBuffer->lockYCbCr(usageFlags, &mYCbCr);
+  if (mLockStatus != OK) {
+    ALOGE("%s: Failed to lock graphic buffer: %s", __func__,
+          statusToString(mLockStatus).c_str());
+  }
+}
+
+YCbCrLockGuard::~YCbCrLockGuard() {
+  if (getStatus() != OK) {
+    return;
+  }
+
+  GraphicBuffer* gBuffer = GraphicBuffer::fromAHardwareBuffer(mHwBuffer.get());
+  if (gBuffer == nullptr) {
+    return;
+  }
+  gBuffer->unlock();
+  status_t status = gBuffer->unlock();
+  if (status != NO_ERROR) {
+    ALOGE("Failed to unlock graphic buffer: %s", statusToString(status).c_str());
+  }
+}
+
+status_t YCbCrLockGuard::getStatus() const {
+  return mLockStatus;
+}
+
+const android_ycbcr& YCbCrLockGuard::operator*() const {
+  LOG_ALWAYS_FATAL_IF(getStatus() != OK,
+                      "Dereferencing unlocked YCbCrLockGuard, status is %s",
+                      statusToString(mLockStatus).c_str());
+  return mYCbCr;
+}
+
+PlanesLockGuard::PlanesLockGuard(std::shared_ptr<AHardwareBuffer> hwBuffer,
+                                 const uint64_t usageFlags, sp<Fence> fence) {
+  if (hwBuffer == nullptr) {
+    ALOGE("%s: Attempting to lock nullptr buffer.", __func__);
+    return;
+  }
+
+  const int32_t rawFence = fence != nullptr ? fence->get() : -1;
+  mLockStatus = static_cast<status_t>(AHardwareBuffer_lockPlanes(
+      hwBuffer.get(), usageFlags, rawFence, nullptr, &mPlanes));
+  if (mLockStatus != OK) {
+    ALOGE("%s: Failed to lock graphic buffer: %s", __func__,
+          statusToString(mLockStatus).c_str());
+  }
+}
+
+PlanesLockGuard::~PlanesLockGuard() {
+  if (getStatus() != OK || mHwBuffer == nullptr) {
+    return;
+  }
+  AHardwareBuffer_unlock(mHwBuffer.get(), /*fence=*/nullptr);
+}
+
+int PlanesLockGuard::getStatus() const {
+  return mLockStatus;
+}
+
+const AHardwareBuffer_Planes& PlanesLockGuard::operator*() const {
+  LOG_ALWAYS_FATAL_IF(getStatus() != OK,
+                      "Dereferencing unlocked PlanesLockGuard, status is %s",
+                      statusToString(mLockStatus).c_str());
+  return mPlanes;
+}
+
 sp<Fence> importFence(const NativeHandle& aidlHandle) {
   if (aidlHandle.fds.size() != 1) {
     return sp<Fence>::make();
diff --git a/services/camera/virtualcamera/util/Util.h b/services/camera/virtualcamera/util/Util.h
index 15f7969..d5b0b1f 100644
--- a/services/camera/virtualcamera/util/Util.h
+++ b/services/camera/virtualcamera/util/Util.h
@@ -18,17 +18,80 @@
 #define ANDROID_COMPANION_VIRTUALCAMERA_UTIL_H
 
 #include <cstdint>
+#include <memory>
 
 #include "aidl/android/companion/virtualcamera/Format.h"
 #include "aidl/android/hardware/camera/common/Status.h"
 #include "aidl/android/hardware/camera/device/StreamBuffer.h"
 #include "android/binder_auto_utils.h"
+#include "android/hardware_buffer.h"
+#include "system/graphics.h"
 #include "ui/Fence.h"
 
 namespace android {
 namespace companion {
 namespace virtualcamera {
 
+// RAII utility class to safely lock AHardwareBuffer and obtain android_ycbcr
+// structure describing YUV plane layout.
+//
+// Access to the buffer is locked immediatelly afer construction.
+class YCbCrLockGuard {
+ public:
+  YCbCrLockGuard(std::shared_ptr<AHardwareBuffer> hwBuffer, uint32_t usageFlags);
+  YCbCrLockGuard(YCbCrLockGuard&& other) = default;
+  ~YCbCrLockGuard();
+
+  // Returns OK if the buffer is successfully locked.
+  status_t getStatus() const;
+
+  // Dereferencing instance of this guard returns android_ycbcr structure
+  // describing the layout.
+  // Caller needs to check whether the buffer was successfully locked
+  // before dereferencing.
+  const android_ycbcr& operator*() const;
+
+  // Disable copy.
+  YCbCrLockGuard(const YCbCrLockGuard&) = delete;
+  YCbCrLockGuard& operator=(const YCbCrLockGuard&) = delete;
+
+ private:
+  std::shared_ptr<AHardwareBuffer> mHwBuffer;
+  android_ycbcr mYCbCr = {};
+  status_t mLockStatus = DEAD_OBJECT;
+};
+
+// RAII utility class to safely lock AHardwareBuffer and obtain
+// AHardwareBuffer_Planes (Suitable for interacting with RGBA / BLOB buffers.
+//
+// Access to the buffer is locked immediatelly afer construction.
+class PlanesLockGuard {
+ public:
+  PlanesLockGuard(std::shared_ptr<AHardwareBuffer> hwBuffer,
+                  uint64_t usageFlags, sp<Fence> fence = nullptr);
+  PlanesLockGuard(PlanesLockGuard&& other) = default;
+  ~PlanesLockGuard();
+
+  // Returns OK if the buffer is successfully locked.
+  status_t getStatus() const;
+
+  // Dereferencing instance of this guard returns AHardwareBuffer_Planes
+  // structure describing the layout.
+  //
+  // Caller needs to check whether the buffer was successfully locked
+  // before dereferencing.
+  const AHardwareBuffer_Planes& operator*() const;
+
+  // Disable copy.
+  PlanesLockGuard(const PlanesLockGuard&) = delete;
+  PlanesLockGuard& operator=(const YCbCrLockGuard&) = delete;
+
+ private:
+  std::shared_ptr<AHardwareBuffer> mHwBuffer;
+  AHardwareBuffer_Planes mPlanes;
+  status_t mLockStatus = DEAD_OBJECT;
+};
+
 // Converts camera AIDL status to ndk::ScopedAStatus
 inline ndk::ScopedAStatus cameraStatus(
     const ::aidl::android::hardware::camera::common::Status status) {