src/trace_processor/storage_table.h

/*
 * 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_STORAGE_TABLE_H_
#define SRC_TRACE_PROCESSOR_STORAGE_TABLE_H_

#include <set>

#include "src/trace_processor/row_iterators.h"
#include "src/trace_processor/sqlite/sqlite_table.h"
#include "src/trace_processor/storage_columns.h"
#include "src/trace_processor/storage_schema.h"

namespace perfetto {
namespace trace_processor {

// Base class for all table implementations which are backed by some data
// storage.
class StorageTable : public SqliteTable {
 public:
  // A cursor which abstracts common patterns found in storage backed tables. It
  // takes a strategy to iterate through rows and a column reporter for each
  // column to implement the Cursor interface.
  class Cursor final : public SqliteTable::Cursor {
   public:
    Cursor(StorageTable* table);

    // Implementation of SqliteTable::Cursor.
    int Filter(const QueryConstraints& qc, sqlite3_value** argv) override;
    int Next() override;
    int Eof() override;
    int Column(sqlite3_context*, int N) override;

   private:
    std::unique_ptr<RowIterator> iterator_;
    std::vector<std::unique_ptr<StorageColumn>>* columns_ = nullptr;
    StorageTable* table_ = nullptr;
  };

  StorageTable();
  virtual ~StorageTable() override;

  // Table implementation.
  util::Status Init(int,
                    const char* const*,
                    SqliteTable::Schema*) override final;
  std::unique_ptr<SqliteTable::Cursor> CreateCursor() override;

  // Required methods for subclasses to implement.
  virtual StorageSchema CreateStorageSchema() = 0;
  virtual uint32_t RowCount() = 0;

 protected:
  const StorageSchema& schema() const { return schema_; }

  bool HasEqConstraint(const QueryConstraints&, const std::string& col_name);

 private:
  // Creates a row iterator which is optimized for a generic storage schema
  // (i.e. it does not make assumptions about values of columns).
  std::unique_ptr<RowIterator> CreateBestRowIterator(const QueryConstraints& qc,
                                                     sqlite3_value** argv);

  FilteredRowIndex CreateRangeIterator(
      const std::vector<QueryConstraints::Constraint>& cs,
      sqlite3_value** argv);

  std::pair<bool, bool> IsOrdered(
      const std::vector<QueryConstraints::OrderBy>& obs);

  std::vector<QueryConstraints::OrderBy> RemoveRedundantOrderBy(
      const std::vector<QueryConstraints::Constraint>& cs,
      const std::vector<QueryConstraints::OrderBy>& obs);

  std::vector<uint32_t> CreateSortedIndexVector(
      FilteredRowIndex index,
      const std::vector<QueryConstraints::OrderBy>& obs);

  StorageSchema schema_;
};

}  // namespace trace_processor
}  // namespace perfetto

#endif  // SRC_TRACE_PROCESSOR_STORAGE_TABLE_H_