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// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef TOOLS_GN_INPUT_FILE_MANAGER_H_
#define TOOLS_GN_INPUT_FILE_MANAGER_H_
#include <mutex>
#include <set>
#include <unordered_map>
#include <utility>
#include <vector>
#include "base/callback.h"
#include "base/files/file_path.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "tools/gn/build_settings.h"
#include "tools/gn/input_file.h"
#include "tools/gn/parse_tree.h"
#include "tools/gn/settings.h"
#include "util/auto_reset_event.h"
class Err;
class LocationRange;
class ParseNode;
class Token;
// Manages loading and parsing files from disk. This doesn't actually have
// any context for executing the results, so potentially multiple configs
// could use the same input file (saving parsing).
//
// This class is threadsafe.
//
// InputFile objects must never be deleted while the program is running since
// various state points into them.
class InputFileManager : public base::RefCountedThreadSafe<InputFileManager> {
public:
// Callback issued when a file is laoded. On auccess, the parse node will
// refer to the root block of the file. On failure, this will be NULL.
typedef base::Callback<void(const ParseNode*)> FileLoadCallback;
InputFileManager();
// Loads the given file and executes the callback on the worker pool.
//
// There are two types of errors. For errors known synchronously, the error
// will be set, it will return false, and no work will be scheduled.
//
// For parse errors and such that happen in the future, the error will be
// logged to the scheduler and the callback will be invoked with a null
// ParseNode pointer. The given |origin| will be blamed for the invocation.
bool AsyncLoadFile(const LocationRange& origin,
const BuildSettings* build_settings,
const SourceFile& file_name,
const FileLoadCallback& callback,
Err* err);
// Loads and parses the given file synchronously, returning the root block
// corresponding to the parsed result. On error, return NULL and the given
// Err is set.
const ParseNode* SyncLoadFile(const LocationRange& origin,
const BuildSettings* build_settings,
const SourceFile& file_name,
Err* err);
// Creates an entry to manage the memory associated with keeping a parsed
// set of code in memory.
//
// The values pointed to by the parameters will be filled with pointers to
// the file, tokens, and parse node that this class created. The calling
// code is responsible for populating these values and maintaining
// threadsafety. This class' only job is to hold onto the memory and delete
// it when the program exits.
//
// This solves the problem that sometimes we need to execute something
// dynamic and save the result, but the values all have references to the
// nodes and file that created it. Either we need to reset the origin of
// the values and lose context for error reporting, or somehow keep the
// associated parse nodes, tokens, and file data in memory. This function
// allows the latter.
void AddDynamicInput(const SourceFile& name,
InputFile** file,
std::vector<Token>** tokens,
std::unique_ptr<ParseNode>** parse_root);
// Does not count dynamic input.
int GetInputFileCount() const;
// Fills the vector with all input files.
void GetAllPhysicalInputFileNames(std::vector<base::FilePath>* result) const;
private:
friend class base::RefCountedThreadSafe<InputFileManager>;
struct InputFileData {
explicit InputFileData(const SourceFile& file_name);
~InputFileData();
// Don't touch this outside the lock until it's marked loaded.
InputFile file;
bool loaded;
bool sync_invocation;
// Lists all invocations that need to be executed when the file completes
// loading.
std::vector<FileLoadCallback> scheduled_callbacks;
// Event to signal when the load is complete (or fails). This is lazily
// created only when a thread is synchronously waiting for this load (which
// only happens for imports).
std::unique_ptr<AutoResetEvent> completion_event;
std::vector<Token> tokens;
// Null before the file is loaded or if loading failed.
std::unique_ptr<ParseNode> parsed_root;
Err parse_error;
};
virtual ~InputFileManager();
void BackgroundLoadFile(const LocationRange& origin,
const BuildSettings* build_settings,
const SourceFile& name,
InputFile* file);
// Loads the given file. On error, sets the Err and return false.
bool LoadFile(const LocationRange& origin,
const BuildSettings* build_settings,
const SourceFile& name,
InputFile* file,
Err* err);
mutable std::mutex lock_;
// Maps repo-relative filenames to the corresponding owned pointer.
typedef std::unordered_map<SourceFile, std::unique_ptr<InputFileData>>
InputFileMap;
InputFileMap input_files_;
// Tracks all dynamic inputs. The data are holders for memory management
// purposes and should not be read or modified by this class. The values
// will be vended out to the code creating the dynamic input, who is in
// charge of the threadsafety requirements.
//
// See AddDynamicInput().
std::vector<std::unique_ptr<InputFileData>> dynamic_inputs_;
DISALLOW_COPY_AND_ASSIGN(InputFileManager);
};
#endif // TOOLS_GN_INPUT_FILE_MANAGER_H_
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