#include "css_summarizer_base.h"

Inheritance diagram for net_instaweb::CssSummarizerBase:

Classes
struct	SummaryInfo

Public Member Functions
	CssSummarizerBase (RewriteDriver *driver)

Public Member Functions inherited from net_instaweb::RewriteFilter
	RewriteFilter (RewriteDriver *driver)

virtual const char *	id () const =0

virtual void	DetermineEnabled (GoogleString *disabled_reason)

virtual bool	CanModifyUrls ()

virtual const UrlSegmentEncoder *	encoder () const

virtual bool	ComputeOnTheFly () const

virtual RewriteContext *	MakeNestedRewriteContext (RewriteContext *parent, const ResourceSlotPtr &slot)

virtual void	EncodeUserAgentIntoResourceContext (ResourceContext *context) const

virtual const RewriteOptions::Filter *	RelatedFilters (int *num_filters) const

virtual const StringPieceVector *	RelatedOptions () const

Public Member Functions inherited from net_instaweb::CommonFilter
	CommonFilter (RewriteDriver *driver)

const GoogleUrl &	base_url () const
	Getters. More...

const GoogleUrl &	decoded_base_url () const

RewriteDriver *	driver () const

HtmlElement *	noscript_element () const

void	InsertNodeAtBodyEnd (HtmlNode *data)

virtual void	StartDocument ()
	Note: Don't overload these methods, overload the implementers instead!

virtual void	StartElement (HtmlElement *element)

virtual void	EndElement (HtmlElement *element)

ResourcePtr	CreateInputResource (StringPiece input_url, RewriteDriver::InputRole role, bool *is_authorized)

ResourcePtr	CreateInputResourceOrInsertDebugComment (StringPiece input_url, RewriteDriver::InputRole role, HtmlElement *element)

void	ResolveUrl (StringPiece input_url, GoogleUrl *out_url)

bool	IsRelativeUrlLoadPermittedByCsp (StringPiece url, CspDirective role)

bool	BaseUrlIsValid () const

bool	DebugMode () const

bool	CanAddPagespeedOnloadToImage (const HtmlElement &)

virtual void	LogFilterModifiedContent ()

virtual RewriteDriver::InlineAuthorizationPolicy	AllowUnauthorizedDomain () const

virtual bool	IntendedForInlining () const

void	AddJsToElement (StringPiece js, HtmlElement *script)

Public Member Functions inherited from net_instaweb::EmptyHtmlFilter
virtual void	Cdata (HtmlCdataNode *cdata)
	Called for CDATA blocks (e.g. <![CDATA[foobar]]>)

virtual void	Comment (HtmlCommentNode *comment)
	Called for HTML comments that aren't IE directives (e.g. ).

virtual void	IEDirective (HtmlIEDirectiveNode *directive)

virtual void	Directive (HtmlDirectiveNode *directive)
	Called for HTML directives (e.g. <!doctype foobar>).

virtual void	Flush ()

ScriptUsage	GetScriptUsage () const override

Public Member Functions inherited from net_instaweb::HtmlFilter
bool	is_enabled () const

void	set_is_enabled (bool is_enabled)

virtual const char *	Name () const =0
	The name of this filter – used for logging and debugging.

Static Public Member Functions
static void	InitStats (Statistics *statistics)

Static Public Member Functions inherited from net_instaweb::RewriteFilter
static StringPiece	GetCharsetForScript (const Resource *script, const StringPiece attribute_charset, const StringPiece enclosing_charset)

static GoogleString	GetCharsetForStylesheet (const Resource *stylesheet, const StringPiece attribute_charset, const StringPiece enclosing_charset)

Static Public Member Functions inherited from net_instaweb::CommonFilter
static bool	ExtractMetaTagDetails (const HtmlElement &element, const ResponseHeaders headers, GoogleString content, GoogleString mime_type, GoogleString charset)

Static Public Attributes
static const char	kNumCssUsedForCriticalCssComputation []

static const char	kNumCssNotUsedForCriticalCssComputation []

Static Public Attributes inherited from net_instaweb::CommonFilter
static const char	kCreateResourceFailedDebugMsg []
	Debug message to be inserted when resource creation fails.

Protected Types
enum	SummaryState { kSummaryOk, kSummaryStillPending, kSummaryCssParseError, kSummaryResourceCreationFailed, kSummaryInputUnavailable, kSummarySlotRemoved }

Protected Member Functions
virtual GoogleString	CacheKeySuffix () const

virtual bool	MustSummarize (HtmlElement *element) const

virtual void	Summarize (Css::Stylesheet stylesheet, GoogleString out) const =0

virtual void	RenderSummary (int pos, HtmlElement element, HtmlCharactersNode char_node, bool *is_element_deleted)

virtual void	WillNotRenderSummary (int pos, HtmlElement element, HtmlCharactersNode char_node)

virtual void	SummariesDone ()

int	NumStyles () const

const SummaryInfo &	GetSummaryForStyle (int pos) const

virtual void	StartDocumentImpl ()

virtual void	EndDocument ()

virtual void	StartElementImpl (HtmlElement *element)

virtual void	Characters (HtmlCharactersNode *characters)

virtual void	EndElementImpl (HtmlElement *element)

virtual void	RenderDone ()

virtual RewriteContext *	MakeRewriteContext ()

Protected Member Functions inherited from net_instaweb::RewriteFilter
virtual const char *	LoggingId ()
	This class logs using id().

Protected Member Functions inherited from net_instaweb::CommonFilter
ServerContext *	server_context () const

const RewriteOptions *	rewrite_options ()

Additional Inherited Members
Public Types inherited from net_instaweb::HtmlFilter
enum	ScriptUsage { kWillInjectScripts, kMayInjectScripts, kNeverInjectsScripts }
	Describes a filter's relationship with scripts. More...

Detailed Description

This class helps implement filters that try to compute some properties of all the screen-affecting CSS in the page except for scoped <style> blocks (which are left untouched). They are expected to override Summarize() to perform the per-CSS computation; then at SummariesDone() they can lookup summaries via NumStyles/GetSummaryForStyle.

Member Enumeration Documentation

enum net_instaweb::CssSummarizerBase::SummaryState

protected

Enumerator
kSummaryOk	All OK!
kSummaryStillPending	Computation/Fetches ongoing, we don't have a result yet.
kSummaryCssParseError	CSS parse error we can't recover from.
kSummaryResourceCreationFailed	Could not create the resource object, so its URL is malformed or we do not have permission to rewrite it.
kSummaryInputUnavailable	Fetch result unusable, either error or not cacheable.
kSummarySlotRemoved	Slot got removed by an another optimization.

Member Function Documentation

virtual GoogleString net_instaweb::CssSummarizerBase::CacheKeySuffix ( ) const

protectedvirtual

This method should be overridden in case the subclass's summary computation depends on things other than the input CSS.

Reimplemented in net_instaweb::CriticalSelectorFilter.

virtual void net_instaweb::CssSummarizerBase::Characters ( HtmlCharactersNode * characters )

protectedvirtual

If a subclass overloads this function and wishes to use InsertNodeAtBodyEnd(), it needs to make an upcall to this implementation for InsertNodeAtBodyEnd() to work correctly.

Reimplemented from net_instaweb::CommonFilter.

virtual void net_instaweb::CssSummarizerBase::EndDocument ( )

protectedvirtual

Note: EndDocument will be called immediately before the last Flush call. (which also means that in the RewriteDriver use it is called before rendering for the last flush window).

Reimplemented from net_instaweb::EmptyHtmlFilter.

Reimplemented in net_instaweb::CriticalSelectorFilter.

const SummaryInfo& net_instaweb::CssSummarizerBase::GetSummaryForStyle ( int pos ) const

inlineprotected

Returns summary computed for the pos'th style in the document.

pos must be in [0, NumStyles())

Should be called from a thread context that has HTML parser state access.

virtual RewriteContext* net_instaweb::CssSummarizerBase::MakeRewriteContext ( )

protectedvirtual

Generates a RewriteContext appropriate for this filter. Default implementation returns NULL. This must be overridden by filters. This is used to implement Fetch.

Reimplemented from net_instaweb::RewriteFilter.

virtual bool net_instaweb::CssSummarizerBase::MustSummarize ( HtmlElement * element ) const

inlineprotectedvirtual

This method should be overridden if some CSS should not go through the summarization process (eg because it uses an inapplicable media type and we'll just throw it away when we're done anyway). By default all CSS must be summarized.

Reimplemented in net_instaweb::CriticalCssBeaconFilter.

int net_instaweb::CssSummarizerBase::NumStyles ( ) const

inlineprotected

Returns total number of <link> and <style> elements we encountered. This includes those for which we had problem computing summary information.

Should be called from a thread context that has HTML parser state access.

virtual void net_instaweb::CssSummarizerBase::RenderDone ( )

protectedvirtual

Notifies a filter that an asynchronous rewrite & render computation phase has finished. This is not used by HtmlParse itself, but only by RewriteDriver for pre-render filters. Happens after the corresponding flush, for every flush window. Default implementation does nothing.

Todo:: TODO(morlovich): Push this down into CommonFilter and convert all the pre-render filters to inherit off it.

Reimplemented from net_instaweb::HtmlFilter.

Reimplemented in net_instaweb::CriticalSelectorFilter.

virtual void net_instaweb::CssSummarizerBase::RenderSummary	(	int	pos,
		HtmlElement *	element,
		HtmlCharactersNode *	char_node,
		bool *	is_element_deleted
	)

protectedvirtual

This can be optionally overridden to modify a CSS element based on a successfully computed summary. It might not be invoked if cached information is not readily available, and will not be invoked if CSS parsing failed or some other error occurred. Invocation occurs from a thread with HTML parser context state, so both DOM modification and GetSummaryForStyle() are safe to use. If invoked, the method will be called before SummariesDone().

pos is the position of the element in the summary table.

element points to the <link> or <style> element that was summarized. If the element was a <style>, char_node will also point to its contents node; otherwise it will be NULL. Overrides need to set is_element_deleted to true if they delete the element.

The default implementation does nothing.

Reimplemented in net_instaweb::CriticalSelectorFilter.

virtual void net_instaweb::CssSummarizerBase::StartDocumentImpl ( )

protectedvirtual

Overrides of the filter APIs. You MUST call through to this class's implementations if you override them.

Implements net_instaweb::CommonFilter.

Reimplemented in net_instaweb::CriticalSelectorFilter.

virtual void net_instaweb::CssSummarizerBase::SummariesDone ( )

protectedvirtual

This is called at the end of the document when all outstanding summary computations have completed, regardless of whether successful or not. It will not be called at all if they are still ongoing, however.

It's called from a context which allows HTML parser state access. You can insert things at end of document by constructing an HtmlNode* using the factories in HtmlParse and calling CommonFilter::InsertNodeAtBodyEnd(node).

Note that the timing of this can vary widely — it can occur during initial parse, during the render phase, or even at RenderDone, so implementors should not make assumptions about what other filters may have done to the DOM.

Base version does nothing.

Reimplemented in net_instaweb::CriticalCssBeaconFilter.

virtual void net_instaweb::CssSummarizerBase::Summarize	(	Css::Stylesheet *	stylesheet,
		GoogleString *	out
	)		const

protectedpure virtual

This should be overridden to compute a per-resource summary. The method should not modify the object state, and only put the result into *out as it may not be invoked in case of a cache hit. The subclass may mutate *stylesheet if it so wishes.

Note: this is called on a rewrite thread, so it should not access HTML parser state.

Implemented in net_instaweb::CriticalCssBeaconFilter, and net_instaweb::CriticalSelectorFilter.

virtual void net_instaweb::CssSummarizerBase::WillNotRenderSummary	(	int	pos,
		HtmlElement *	element,
		HtmlCharactersNode *	char_node
	)

protectedvirtual

Like RenderSummary, but called in cases where we're unable to render a summary for some reason (including not being able to compute one). Note: not called when we're canceled due to disable_further_processing.

Like with RenderSummary, this corresponds to entry [pos] in the summary table, and elements points to the <link> or <style> containing CSS, with char_node being non-null in case it was a <style>.

Reimplemented in net_instaweb::CriticalSelectorFilter.

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

net/instaweb/rewriter/public/css_summarizer_base.h

Classes

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Types

Protected Member Functions

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

Member Function Documentation