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/*
* Copyright (C) 2019 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_DB_TABLE_H_
#define SRC_TRACE_PROCESSOR_DB_TABLE_H_
#include <stdint.h>
#include <limits>
#include <numeric>
#include <vector>
#include "perfetto/base/logging.h"
#include "perfetto/ext/base/optional.h"
#include "src/trace_processor/containers/string_pool.h"
#include "src/trace_processor/db/column.h"
#include "src/trace_processor/db/column_storage_overlay.h"
#include "src/trace_processor/db/typed_column.h"
namespace perfetto {
namespace trace_processor {
// Represents a table of data with named, strongly typed columns.
class Table {
public:
// Iterator over the rows of the table.
class Iterator {
public:
explicit Iterator(const Table* table) : table_(table) {
its_.reserve(table->overlays().size());
for (const auto& rm : table->overlays()) {
its_.emplace_back(rm.IterateRows());
}
}
Iterator(Iterator&&) noexcept = default;
Iterator& operator=(Iterator&&) = default;
Iterator(const Iterator&) = delete;
Iterator& operator=(const Iterator&) = delete;
// Advances the iterator to the next row of the table.
void Next() {
for (auto& it : its_) {
it.Next();
}
}
// Returns whether the row the iterator is pointing at is valid.
explicit operator bool() const { return its_[0]; }
// Returns the value at the current row for column |col_idx|.
SqlValue Get(uint32_t col_idx) const {
const auto& col = table_->columns_[col_idx];
return col.GetAtIdx(its_[col.overlay_index()].index());
}
private:
const Table* table_ = nullptr;
std::vector<ColumnStorageOverlay::Iterator> its_;
};
// Helper class storing the schema of the table. This allows decisions to be
// made about operations on the table without materializing the table - this
// may be expensive for dynamically computed tables.
//
// Subclasses of Table usually provide a method (named Schema()) to statically
// generate an instance of this class.
struct Schema {
struct Column {
std::string name;
SqlValue::Type type;
bool is_id;
bool is_sorted;
bool is_hidden;
bool is_set_id;
};
std::vector<Column> columns;
};
Table();
virtual ~Table();
// We explicitly define the move constructor here because we need to update
// the Table pointer in each column in the table.
Table(Table&& other) noexcept { *this = std::move(other); }
Table& operator=(Table&& other) noexcept;
// Filters the Table using the specified filter constraints.
Table Filter(
const std::vector<Constraint>& cs,
RowMap::OptimizeFor optimize_for = RowMap::OptimizeFor::kMemory) const {
if (cs.empty())
return Copy();
return Apply(FilterToRowMap(cs, optimize_for));
}
// Filters the Table using the specified filter constraints optionally
// specifying what the returned RowMap should optimize for.
// Returns a RowMap which, if applied to the table, would contain the rows
// post filter.
RowMap FilterToRowMap(
const std::vector<Constraint>& cs,
RowMap::OptimizeFor optimize_for = RowMap::OptimizeFor::kMemory) const {
RowMap rm(0, row_count_, optimize_for);
for (const Constraint& c : cs) {
columns_[c.col_idx].FilterInto(c.op, c.value, &rm);
}
return rm;
}
// Applies the given RowMap to the current table by picking out the rows
// specified in the RowMap to be present in the output table.
// Note: the RowMap should not reorder this table; this is guaranteed if the
// passed RowMap is generated using |FilterToRowMap|.
Table Apply(RowMap rm) const {
Table table = CopyExceptRowMaps();
table.row_count_ = rm.size();
table.overlays_.reserve(overlays_.size());
for (const ColumnStorageOverlay& map : overlays_) {
table.overlays_.emplace_back(map.SelectRows(rm));
PERFETTO_DCHECK(table.overlays_.back().size() == table.row_count());
}
// Pretty much any application of a RowMap will break the requirements on
// kSetId so remove it.
for (auto& col : table.columns_) {
col.flags_ &= ~Column::Flag::kSetId;
}
return table;
}
// Sorts the Table using the specified order by constraints.
Table Sort(const std::vector<Order>& od) const;
// Returns the column at index |idx| in the Table.
const Column& GetColumn(uint32_t idx) const { return columns_[idx]; }
// Returns the column index with the given name or base::nullopt otherwise.
base::Optional<uint32_t> GetColumnIndexByName(const char* name) const {
auto it = std::find_if(
columns_.begin(), columns_.end(),
[name](const Column& col) { return strcmp(col.name(), name) == 0; });
if (it == columns_.end())
return base::nullopt;
return static_cast<uint32_t>(std::distance(columns_.begin(), it));
}
// Returns the column with the given name or nullptr otherwise.
const Column* GetColumnByName(const char* name) const {
base::Optional<uint32_t> opt_idx = GetColumnIndexByName(name);
if (!opt_idx)
return nullptr;
return &columns_[*opt_idx];
}
template <typename T>
const TypedColumn<T>& GetTypedColumnByName(const char* name) const {
return *TypedColumn<T>::FromColumn(GetColumnByName(name));
}
template <typename T>
const IdColumn<T>& GetIdColumnByName(const char* name) const {
return *IdColumn<T>::FromColumn(GetColumnByName(name));
}
// Returns the number of columns in the Table.
uint32_t GetColumnCount() const {
return static_cast<uint32_t>(columns_.size());
}
// Returns an iterator into the Table.
Iterator IterateRows() const { return Iterator(this); }
// Creates a copy of this table.
Table Copy() const;
// Computes the schema of this table and returns it.
Schema ComputeSchema() const {
Schema schema;
schema.columns.reserve(columns_.size());
for (const auto& col : columns_) {
schema.columns.emplace_back(
Schema::Column{col.name(), col.type(), col.IsId(), col.IsSorted(),
col.IsHidden(), col.IsSetId()});
}
return schema;
}
uint32_t row_count() const { return row_count_; }
StringPool* string_pool() const { return string_pool_; }
const std::vector<ColumnStorageOverlay>& overlays() const {
return overlays_;
}
const std::vector<Column>& columns() const { return columns_; }
protected:
explicit Table(StringPool* pool);
std::vector<ColumnStorageOverlay> CopyOverlays() const {
std::vector<ColumnStorageOverlay> rm(overlays_.size());
for (uint32_t i = 0; i < overlays_.size(); ++i) {
rm[i] = overlays_[i].Copy();
}
return rm;
}
std::vector<ColumnStorageOverlay> overlays_;
std::vector<Column> columns_;
uint32_t row_count_ = 0;
StringPool* string_pool_ = nullptr;
private:
friend class Column;
friend class View;
Table CopyExceptRowMaps() const;
};
} // namespace trace_processor
} // namespace perfetto
#endif // SRC_TRACE_PROCESSOR_DB_TABLE_H_