Add metadata helper class.

Breaks metadata down into distinct pieces (to be added later).

BUG: 29330282
TEST: unit tests pass

Change-Id: I7156e420e7cdb14b5c3155006ecefd8ff2a49500
diff --git a/modules/camera/3_4/v4l2_metadata.cpp b/modules/camera/3_4/v4l2_metadata.cpp
new file mode 100644
index 0000000..54d2809
--- /dev/null
+++ b/modules/camera/3_4/v4l2_metadata.cpp
@@ -0,0 +1,143 @@
+/*
+ * Copyright 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.
+ */
+
+#include "v4l2_metadata.h"
+
+#include <camera/CameraMetadata.h>
+
+#include "common.h"
+
+namespace v4l2_camera_hal {
+
+V4L2Metadata::V4L2Metadata(V4L2Wrapper* device) : device_(device) {
+  HAL_LOG_ENTER();
+
+  PopulateComponents();
+}
+
+V4L2Metadata::~V4L2Metadata() { HAL_LOG_ENTER(); }
+
+void V4L2Metadata::PopulateComponents() {
+  HAL_LOG_ENTER();
+
+  // TODO(arihc): Add all default components.
+}
+
+void V4L2Metadata::AddComponent(
+    std::unique_ptr<PartialMetadataInterface> component) {
+  HAL_LOG_ENTER();
+
+  components_.push_back(std::move(component));
+}
+
+int V4L2Metadata::FillStaticMetadata(camera_metadata_t** metadata) {
+  HAL_LOG_ENTER();
+
+  std::vector<int32_t> static_tags;
+  std::vector<int32_t> control_tags;
+  std::vector<int32_t> dynamic_tags;
+  int res = 0;
+
+  for (auto& component : components_) {
+    // Populate the fields.
+    res = component->PopulateStaticFields(metadata);
+    if (res) {
+      // Exit on error.
+      HAL_LOGE("Failed to get all static properties.");
+      return res;
+    }
+
+    // Note what tags the component adds.
+    const std::vector<int32_t>* tags = &component->StaticTags();
+    static_tags.insert(static_tags.end(), tags->begin(), tags->end());
+    tags = &component->ControlTags();
+    control_tags.insert(control_tags.end(), tags->begin(), tags->end());
+    tags = &component->DynamicTags();
+    dynamic_tags.insert(dynamic_tags.end(), tags->begin(), tags->end());
+  }
+
+  // Populate the meta fields.
+  android::CameraMetadata metadata_wrapper(*metadata);
+  static_tags.push_back(ANDROID_REQUEST_AVAILABLE_REQUEST_KEYS);
+  res = metadata_wrapper.update(ANDROID_REQUEST_AVAILABLE_REQUEST_KEYS,
+                                control_tags.data(), control_tags.size());
+  if (res != android::OK) {
+    HAL_LOGE("Failed to add request keys meta key.");
+    return -ENODEV;
+  }
+  static_tags.push_back(ANDROID_REQUEST_AVAILABLE_RESULT_KEYS);
+  res = metadata_wrapper.update(ANDROID_REQUEST_AVAILABLE_RESULT_KEYS,
+                                dynamic_tags.data(), dynamic_tags.size());
+  if (res != android::OK) {
+    HAL_LOGE("Failed to add result keys meta key.");
+    return -ENODEV;
+  }
+  static_tags.push_back(ANDROID_REQUEST_AVAILABLE_CHARACTERISTICS_KEYS);
+  res = metadata_wrapper.update(ANDROID_REQUEST_AVAILABLE_CHARACTERISTICS_KEYS,
+                                static_tags.data(), static_tags.size());
+  if (res != android::OK) {
+    HAL_LOGE("Failed to add characteristics keys meta key.");
+    return -ENODEV;
+  }
+
+  *metadata = metadata_wrapper.release();
+  return 0;
+}
+
+bool V4L2Metadata::IsValidRequest(const camera_metadata_t* metadata) {
+  HAL_LOG_ENTER();
+
+  for (auto& component : components_) {
+    // Check that all components support the values requested of them.
+    bool valid_request = component->SupportsRequestValues(metadata);
+    if (!valid_request) {
+      // Exit early if possible.
+      return false;
+    }
+  }
+
+  return true;
+}
+
+int V4L2Metadata::SetRequestSettings(const camera_metadata_t* metadata) {
+  HAL_LOG_ENTER();
+
+  for (auto& component : components_) {
+    int res = component->SetRequestValues(metadata);
+    if (res) {
+      // Exit early if possible.
+      HAL_LOGE("Failed to set all requested settings.");
+      return res;
+    }
+  }
+
+  return 0;
+}
+
+int V4L2Metadata::FillResultMetadata(camera_metadata_t** metadata) {
+  for (auto& component : components_) {
+    int res = component->PopulateDynamicFields(metadata);
+    if (res) {
+      // Exit early if possible.
+      HAL_LOGE("Failed to get all dynamic result fields.");
+      return res;
+    }
+  }
+
+  return 0;
+}
+
+}  // namespace v4l2_camera_hal