tp: implement CREATE_FUNCTION SQL function
This allows defining functions directly from SQL. This will make writing
reusable snippets of code a lot more lightweight.
Change-Id: If6207fac3815b9b584da9648a0fdc525f2f63670
Bug: 190219056
diff --git a/src/trace_processor/sqlite/create_function.h b/src/trace_processor/sqlite/create_function.h
new file mode 100644
index 0000000..c6778c2
--- /dev/null
+++ b/src/trace_processor/sqlite/create_function.h
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+
+#ifndef SRC_TRACE_PROCESSOR_SQLITE_CREATE_FUNCTION_H_
+#define SRC_TRACE_PROCESSOR_SQLITE_CREATE_FUNCTION_H_
+
+#include <sqlite3.h>
+#include <unordered_map>
+
+#include "src/trace_processor/sqlite/register_function.h"
+
+namespace perfetto {
+namespace trace_processor {
+
+// Implementation of CREATE_FUNCTION SQL function.
+// See https://perfetto.dev/docs/analysis/metrics#metric-helper-functions for
+// usage of this function.
+struct CreateFunction : public SqlFunction {
+ struct PerFunctionState {
+ ScopedStmt stmt;
+ // void* to avoid leaking state.
+ void* created_functon_context;
+ };
+ struct NameAndArgc {
+ std::string name;
+ int argc;
+
+ struct Hasher {
+ std::size_t operator()(const NameAndArgc& s) const noexcept;
+ };
+ bool operator==(const NameAndArgc& other) const {
+ return name == other.name && argc == other.argc;
+ }
+ };
+ using State = std::unordered_map<NameAndArgc,
+ CreateFunction::PerFunctionState,
+ NameAndArgc::Hasher>;
+
+ struct Context {
+ sqlite3* db;
+ State* state;
+ };
+
+ static base::Status Run(Context* ctx,
+ size_t argc,
+ sqlite3_value** argv,
+ SqlValue& out,
+ Destructors&);
+};
+
+} // namespace trace_processor
+} // namespace perfetto
+
+#endif // SRC_TRACE_PROCESSOR_SQLITE_CREATE_FUNCTION_H_
