#include "mem_file_system.h"

Inheritance diagram for net_instaweb::MemFileSystem:

Public Types
typedef Callback1< const GoogleString & >	FileCallback

Public Member Functions
	MemFileSystem (ThreadSystem threads, Timer timer)

virtual InputFile *	OpenInputFile (const char filename, MessageHandler message_handler)

virtual OutputFile *	OpenOutputFileHelper (const char filename, bool append, MessageHandler message_handler)

virtual OutputFile *	OpenTempFileHelper (const StringPiece &prefix_name, MessageHandler *message_handle)

virtual bool	ListContents (const StringPiece &dir, StringVector files, MessageHandler handler)

virtual bool	MakeDir (const char directory_path, MessageHandler handler)

virtual bool	RecursivelyMakeDir (const StringPiece &directory_path, MessageHandler *handler)

virtual bool	RemoveDir (const char path, MessageHandler handler)
	Like POSIX 'rmdir', remove a directory only if it is empty.

virtual bool	RemoveFile (const char filename, MessageHandler handler)
	Like POSIX 'rm'.

virtual bool	RenameFileHelper (const char old_file, const char new_file, MessageHandler *handler)

virtual bool	Atime (const StringPiece &path, int64 timestamp_sec, MessageHandler handler)

virtual bool	Mtime (const StringPiece &path, int64 timestamp_sec, MessageHandler handler)
	Modified time. Time the file contents were modified.

virtual bool	Size (const StringPiece &path, int64 size, MessageHandler handler) const

virtual BoolOrError	Exists (const char path, MessageHandler handler)
	Like POSIX 'test -e', checks if path exists (is a file, directory, etc.).

virtual BoolOrError	IsDir (const char path, MessageHandler handler)
	Like POSIX 'test -d', checks if path exists and refers to a directory.

virtual BoolOrError	TryLock (const StringPiece &lock_name, MessageHandler *handler)

virtual BoolOrError	TryLockWithTimeout (const StringPiece &lock_name, int64 timeout_ms, const Timer timer, MessageHandler handler)

virtual bool	BumpLockTimeout (const StringPiece &lock_name, MessageHandler *handler)

virtual bool	Unlock (const StringPiece &lock_name, MessageHandler *handler)

void	set_atime_enabled (bool enabled)
	When atime is disabled, reading a file will not update its atime.

bool	advance_time_on_update ()

void	set_advance_time_on_update (bool x, MockTimer *mock_timer)

void	Clear ()

void	Disable ()
	Test-specific functionality to disable and re-enable the filesystem.

void	Enable ()

void	ClearStats ()
	Access statistics.

int	num_input_file_opens () const

int	num_input_file_stats () const
	returns number of times MTime was called.

int	num_output_file_opens () const

int	num_temp_file_opens () const

void	set_write_callback (FileCallback *x)

virtual bool	WriteFile (const char filename, const StringPiece &buffer, MessageHandler handler)
	Non-atomic. Use WriteFileAtomic() for atomic version.

virtual bool	WriteTempFile (const StringPiece &prefix_name, const StringPiece &buffer, GoogleString filename, MessageHandler handler)

Public Member Functions inherited from net_instaweb::FileSystem
virtual int	MaxPathLength (const StringPiece &base) const

virtual bool	ReadFile (const char filename, int64 max_file_size, Writer writer, MessageHandler *handler)

virtual bool	ReadFile (InputFile input_file, int64 max_file_size, Writer writer, MessageHandler *handler)

virtual bool	ReadFile (const char filename, int64 max_file_size, GoogleString buffer, MessageHandler *handler)

virtual bool	ReadFile (InputFile input_file, int64 max_file_size, GoogleString buffer, MessageHandler *handler)

virtual bool	ReadFile (const char filename, GoogleString buffer, MessageHandler *handler)

virtual bool	ReadFile (InputFile input_file, GoogleString buffer, MessageHandler *handler)

virtual bool	ReadFile (const char filename, Writer writer, MessageHandler *handler)

virtual bool	ReadFile (InputFile input_file, Writer writer, MessageHandler *handler)

bool	WriteFileAtomic (const StringPiece &filename, const StringPiece &buffer, MessageHandler *handler)

OutputFile *	OpenOutputFile (const char filename, MessageHandler handler)
	Automatically creates sub-directories to filename.

OutputFile *	OpenOutputFileForAppend (const char filename, MessageHandler handler)

OutputFile *	OpenTempFile (const StringPiece &prefix_name, MessageHandler *handler)

virtual bool	Close (File file, MessageHandler handler)
	Closes the File and cleans up memory.

bool	RenameFile (const char old_filename, const char new_filename, MessageHandler *handler)

void	GetDirInfo (const StringPiece &path, DirInfo dirinfo, MessageHandler handler)

virtual void	GetDirInfoWithProgress (const StringPiece &path, DirInfo dirinfo, ProgressNotifier notifier, MessageHandler *handler)

Additional Inherited Members
Static Public Attributes inherited from net_instaweb::FileSystem
static const int64	kUnlimitedSize = -1
	This is documented as -1 in user-facing documentation, so don't change it.

Detailed Description

An in-memory implementation of the FileSystem interface. This was originally for use in unit tests; but can also host the lock manager if needed. Does not fully support directories. Not particularly efficient. Not threadsafe except for lock methods.

Todo:: TODO(abliss): add an ability to block writes for arbitrarily long, to enable testing resilience to concurrency problems with real filesystems.

Todo:: TODO(jmarantz): make threadsafe.

Member Function Documentation

bool net_instaweb::MemFileSystem::advance_time_on_update ( )

inline

In order to test file-system 'atime' code, we need to move mock time forward during tests by an entire second (aka 1000 ms). However, that's disruptive to other tests that try to use mock-time to examine millisecond-level timing, so we leave this behavior off by default.

virtual bool net_instaweb::MemFileSystem::Atime	(	const StringPiece &	path,
		int64 *	timestamp_sec,
		MessageHandler *	handler
	)

virtual

We offer a "simulated atime" in which the clock ticks forward one second every time you read or write a file.

Implements net_instaweb::FileSystem.

virtual bool net_instaweb::MemFileSystem::BumpLockTimeout	(	const StringPiece &	lock_name,
		MessageHandler *	handler
	)

virtual

If you're holding a lock for a long running task you want to avoid someone else receiving the lock if they request it with TryLockWithTimeout because you've been working for longer than the timeout, you should bump it often enough that it doesn't expire.

Default implementation does nothing, since the default implementation of TryLockWithTimeout doesn't do anything either.

Reimplemented from net_instaweb::FileSystem.

void net_instaweb::MemFileSystem::Clear ( )

Empties out the entire filesystem. Should not be called while files are open.

virtual bool net_instaweb::MemFileSystem::ListContents	(	const StringPiece &	dir,
		StringVector *	files,
		MessageHandler *	handler
	)

virtual

Like POSIX 'ls -a', lists all files and directories under the given directory (but omits "." and ".."). Full paths (not just filenames) will be pushed onto the back of the supplied vector (without clearing it). Returns true on success (even if the dir was empty), false on error (even if some files were pushed onto the vector). This is generally not threadsafe! Use a mutex.

Implements net_instaweb::FileSystem.

virtual bool net_instaweb::MemFileSystem::MakeDir	(	const char *	directory_path,
		MessageHandler *	handler
	)

virtual

Like POSIX 'mkdir', makes a directory only if parent directory exists. Fails if directory_name already exists or parent directory doesn't exist.

Implements net_instaweb::FileSystem.

virtual OutputFile* net_instaweb::MemFileSystem::OpenOutputFileHelper	(	const char *	filename,
		bool	append,
		MessageHandler *	handler
	)

virtual

These interfaces must be defined by implementers of FileSystem. They may assume the directory already exists.

Implements net_instaweb::FileSystem.

virtual bool net_instaweb::MemFileSystem::RecursivelyMakeDir	(	const StringPiece &	directory_path,
		MessageHandler *	handler
	)

virtual

Like POSIX 'mkdir -p', makes all directories up to this one recursively. Fails if we do not have permission to make any directory in chain.

Reimplemented from net_instaweb::FileSystem.

void net_instaweb::MemFileSystem::set_write_callback ( FileCallback * x )

inline

Adds a callback to be called once after a file-write and then deleted.

This is intended primarily for testing, and thus is not on the base class.

virtual bool net_instaweb::MemFileSystem::Size	(	const StringPiece &	path,
		int64 *	size,
		MessageHandler *	handler
	)		const

virtual

Given a file, computes its size in bytes and store it in *size. Returns true on success, false on failure. Behavior is undefined if path refers to a directory. This function has different behavior depending on the underlying implementation. Memory-based implementations will report the size of the file, while disk-based implementations should return the actual allocated size on disk.

Todo:: TODO(abliss): replace this with a single Stat() function.

Implements net_instaweb::FileSystem.

virtual BoolOrError net_instaweb::MemFileSystem::TryLock	(	const StringPiece &	lock_name,
		MessageHandler *	handler
	)

virtual

Attempts to obtain a global (cross-process, cross-thread) lock of the given name (which should be a valid filename, not otherwise used, in an extant directory). If someone else has this lock, returns False immediately. If anything goes wrong, returns Error. On success, returns True: then you must call Unlock when you are done.

Implements net_instaweb::FileSystem.

virtual BoolOrError net_instaweb::MemFileSystem::TryLockWithTimeout	(	const StringPiece &	lock_name,
		int64	timeout_millis,
		const Timer *	timer,
		MessageHandler *	handler
	)

virtual

Like TryLock, but may attempt to break stale locks, though the default implementation never actually breaks any. A lock is stale if it was taken (or last bumped) more than timeout_millis ms ago.

If you obtain a lock through this method, there are no hard guarantees that nobody else has it too. <blink> If you use this function, your lock becomes "best-effort". </blink>

If you override this function, you need to override BumpLockTimeout as well.

Reimplemented from net_instaweb::FileSystem.

virtual bool net_instaweb::MemFileSystem::Unlock	(	const StringPiece &	lock_name,
		MessageHandler *	handler
	)

virtual

Attempts to release a lock previously obtained through TryLock. If your thread did not previously obtain the lock, the behavior is undefined. Returns true if we successfully release the lock. Returns false if we were unable to release the lock (e.g. somebody came along and write-protected the lockfile). You might try again, or start using a different lock name.

Implements net_instaweb::FileSystem.

virtual bool net_instaweb::MemFileSystem::WriteTempFile	(	const StringPiece &	prefix_name,
		const StringPiece &	buffer,
		GoogleString *	filename,
		MessageHandler *	handler
	)

virtual

Writes given data to a temp file in one shot, storing the filename in filename on success. Returns false and clears filename on failure.

Reimplemented from net_instaweb::FileSystem.

The documentation for this class was generated from the following file:

pagespeed/kernel/base/mem_file_system.h

Public Types

Public Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation