Save metadata to Disk

Bug: 148280505
Test: bit statsd_test:*
Change-Id: Ib9c6b9b4f22e7380717b480c7ae4a37bb3364619
diff --git a/cmds/statsd/src/metadata_util.cpp b/cmds/statsd/src/metadata_util.cpp
new file mode 100644
index 0000000..bfe850f
--- /dev/null
+++ b/cmds/statsd/src/metadata_util.cpp
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2020 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 "FieldValue.h"
+#include "metadata_util.h"
+
+namespace android {
+namespace os {
+namespace statsd {
+
+void writeValueToProto(metadata::FieldValue* metadataFieldValue, const Value& value) {
+    std::string storage_value;
+    switch (value.getType()) {
+        case INT:
+            metadataFieldValue->set_value_int(value.int_value);
+            break;
+        case LONG:
+            metadataFieldValue->set_value_long(value.long_value);
+            break;
+        case FLOAT:
+            metadataFieldValue->set_value_float(value.float_value);
+            break;
+        case DOUBLE:
+            metadataFieldValue->set_value_double(value.double_value);
+            break;
+        case STRING:
+            metadataFieldValue->set_value_str(value.str_value.c_str());
+            break;
+        case STORAGE: // byte array
+            storage_value = ((char*) value.storage_value.data());
+            metadataFieldValue->set_value_storage(storage_value);
+            break;
+        default:
+            break;
+    }
+}
+
+void writeMetricDimensionKeyToMetadataDimensionKey(
+        const MetricDimensionKey& metricKey,
+        metadata::MetricDimensionKey* metadataMetricKey) {
+    for (const FieldValue& fieldValue : metricKey.getDimensionKeyInWhat().getValues()) {
+        metadata::FieldValue* metadataFieldValue = metadataMetricKey->add_dimension_key_in_what();
+        metadata::Field* metadataField = metadataFieldValue->mutable_field();
+        metadataField->set_tag(fieldValue.mField.getTag());
+        metadataField->set_field(fieldValue.mField.getField());
+        writeValueToProto(metadataFieldValue, fieldValue.mValue);
+    }
+
+    for (const FieldValue& fieldValue : metricKey.getStateValuesKey().getValues()) {
+        metadata::FieldValue* metadataFieldValue = metadataMetricKey->add_state_values_key();
+        metadata::Field* metadataField = metadataFieldValue->mutable_field();
+        metadataField->set_tag(fieldValue.mField.getTag());
+        metadataField->set_field(fieldValue.mField.getField());
+        writeValueToProto(metadataFieldValue, fieldValue.mValue);
+    }
+}
+
+}  // namespace statsd
+}  // namespace os
+}  // namespace android
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