Class to help run an asynchronous fetch synchronously with a timeout. More...

#include "sync_fetcher_adapter_callback.h"

Inheritance diagram for net_instaweb::SyncFetcherAdapterCallback:

Public Member Functions
	SyncFetcherAdapterCallback (ThreadSystem thread_system, Writer writer, const RequestContextPtr &request_context)

void	Release () LOCKS_EXCLUDED(mutex_)

bool	IsDone () const LOCKS_EXCLUDED(mutex_)

bool	IsDoneLockHeld () const EXCLUSIVE_LOCKS_REQUIRED(mutex_)
	Version of IsDone() that may only be called if you already hold the mutex.

bool	success () const LOCKS_EXCLUDED(mutex_)

bool	released () const LOCKS_EXCLUDED(mutex_)

bool	LockIfNotReleased () EXCLUSIVE_TRYLOCK_FUNCTION(true

void	Unlock () UNLOCK_FUNCTION(mutex_)
	Releases mutex acquired by a successful LockIfNotReleased() call.

void	TimedWait (int64 timeout_ms) EXCLUSIVE_LOCKS_REQUIRED(mutex_)

Public Member Functions inherited from net_instaweb::AsyncFetch
	AsyncFetch (const RequestContextPtr &request_ctx)

void	HeadersComplete ()

void	Done (bool success)

virtual bool	Write (const StringPiece &content, MessageHandler *handler)

virtual bool	Flush (MessageHandler *handler)

virtual bool	IsCachedResultValid (const ResponseHeaders &headers)

RequestHeaders *	request_headers ()

void	set_request_headers (RequestHeaders *headers)

void	SetRequestHeadersTakingOwnership (RequestHeaders *headers)
	Same as above, but takes ownership.

const RequestHeaders *	request_headers () const

ResponseHeaders *	response_headers ()
	See doc for request_headers and set_request_headers.

void	set_response_headers (ResponseHeaders *headers)

ResponseHeaders *	extra_response_headers ()

void	set_extra_response_headers (ResponseHeaders *headers)

virtual bool	IsBackgroundFetch () const

virtual void	Reset ()

bool	headers_complete () const

bool	content_length_known () const

int64	content_length () const

void	set_content_length (int64 x)

GoogleString	LoggingString ()

virtual const RequestContextPtr &	request_context ()

virtual AbstractLogRecord *	log_record ()

void	FixCacheControlForGoogleCache ()

Public Member Functions inherited from net_instaweb::Writer
virtual bool	Dump (Writer writer, MessageHandler message_handler)

Public Attributes
bool	mutex_

Protected Member Functions
virtual void	HandleDone (bool success) LOCKS_EXCLUDED(mutex_)

virtual bool	HandleWrite (const StringPiece &content, MessageHandler *handler)

virtual bool	HandleFlush (MessageHandler *handler)

virtual void	HandleHeadersComplete ()

Additional Inherited Members
Static Public Member Functions inherited from net_instaweb::AsyncFetch
static bool	IsGoogleCacheVia (StringPiece via_value)

Static Public Attributes inherited from net_instaweb::AsyncFetch
static const int	kContentLengthUnknown = -1

Detailed Description

Class to help run an asynchronous fetch synchronously with a timeout.

Member Function Documentation

bool net_instaweb::SyncFetcherAdapterCallback::LockIfNotReleased ( )

If this fetcher hasn't yet been Released(), returns true with mutex_ held. Otherwise, returns false with the mutex_ released. These methods should be used to guard accesses to writer() and response_headers().

void net_instaweb::SyncFetcherAdapterCallback::Release ( )

When implementing a synchronous fetch with a timeout based on an underlying asynchronous mechanism, we need to ensure that we don't write to freed memory if the Done callback fires after the timeout.

So we need to make sure the Writer and Response Buffers are owned by this Callback class, which will forward the output and headers to the caller if it has not been released by the time the callback is called.

If this object may be accessed from multiple threads (e.g. due to async rewrites), you should use LockIfNotReleased() and Unlock() to guard access to these. When the 'owner' of this callback – the code that calls 'new' – is done with it, it can call Release(). That will arrange for the object to be deleted as soon as it's safe to do so, which may be immediately at the point of call, or from some asynchronous event. The object should not be used by the owner after Release() has been called.

void net_instaweb::SyncFetcherAdapterCallback::TimedWait ( int64 timeout_ms )

Waits on condition variable associated with the mutex, with timeout of timeout_ms. The wake up condition is Done() being called, but this merely waits for lookup and does not ensure the condition has occurred — the caller should use a while loop conditioned on done_lock_held(). Should not be called if this callback is already released, and expects mutex already held.

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

net/instaweb/http/public/sync_fetcher_adapter_callback.h

Public Member Functions

Public Attributes

Protected Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation