Alfredo's Loader Queue.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@6221 a592a061-630c-0410-9148-cb99ea01b6c8

lib/CREDITS

@@ -34,6 +34,9 @@
    and a few other (not so) minor things, like 
    rewriting most of the LyX kernel. Also current
    source maintainer.
+@bAlfredo Braunstein
+@iE-mail: abraunst@libero.it
+   a (psuedo) threaded graphics loader queue
 @bChristian Buescher 
    user-definable keys, lyxserver and more
 @bFrancesc Burrull i Mestres

lib/ChangeLog

@@ -4,6 +4,10 @@
 	* examples/de_beispiel_roh.lyx: Small fixes to make it look like a German
 	  document
 
+2003-02-21  Angus Leeming  <leeming@lyx.org>
+
+	* CREDITS: Add Alfredo Braunstein.
+
 2003-02-21  Angus Leeming  <leeming@lyx.org>
 
 	* ui/default.ui: change bibkey-insert to bibtem-insert.

src/graphics/ChangeLog

@@ -1,3 +1,11 @@
+2003-02-20  Alfredo Braunstein  <abraunst@libero.it>
+
+	* LoaderQueue.[Ch]: added. Implements a service queue that loads
+	images in background
+	* GraphicsSupport.[Ch]: removed
+	* Makefile.am: the changes above
+	* GraphicsLoader.C: use the loading queue
+
 2003-01-21  Angus Leeming  <leeming@lyx.org>
 
 	* PreviewLoader.C (dumpPreamble): ensure that \lyxlock does not prevent

src/graphics/GraphicsLoader.C

@@ -18,7 +18,7 @@
 #include "GraphicsCacheItem.h"
 #include "GraphicsImage.h"
 #include "GraphicsParams.h"
-#include "GraphicsSupport.h"
+#include "LoaderQueue.h"
 
 #include "frontends/LyXView.h"
 #include "frontends/Timeout.h"
@@ -66,8 +66,6 @@ private:
 	///
 	Params params_;
 
-	///
-	Timeout timer;
 	// Multiple Insets can share the same image
 	typedef std::list<Inset const *> InsetList;
 	///
@@ -196,10 +194,8 @@ Image const * Loader::image() const
 
 
 Loader::Impl::Impl(Params const & params)
-	: status_(WaitingToLoad), params_(params),
-	  timer(2000, Timeout::ONETIME)
+	: status_(WaitingToLoad), params_(params)
 {
-	timer.timeout.connect(boost::bind(&Impl::checkedLoading, this));
 }
 
 
@@ -293,7 +289,7 @@ void Loader::Impl::createPixmap()
 
 void Loader::Impl::startLoading(Inset const & inset, BufferView const & bv)
 {
-	if (status_ != WaitingToLoad || timer.running())
+	if (status_ != WaitingToLoad)
 		return;
 
 	InsetList::const_iterator it  = insets.begin();
@@ -303,46 +299,7 @@ void Loader::Impl::startLoading(Inset const & inset, BufferView const & bv)
 		insets.push_back(&inset);
 	view = bv.owner()->view();
 
-	timer.start();
-}
-
-
-namespace {
-
-struct FindVisibleInset {
-
-	FindVisibleInset(std::list<VisibleParagraph> const & vps) : vps_(vps) {}
-
-	bool operator()(Inset const * inset_ptr)
-	{
-		if (!inset_ptr)
-			return false;
-		return isInsetVisible(*inset_ptr, vps_);
-	}
-
-private:
-	std::list<VisibleParagraph> const & vps_;
-};
-
-} // namespace anon
-
-
-void Loader::Impl::checkedLoading()
-{
-	if (insets.empty() || !view.get())
-		return;
-
-	std::list<VisibleParagraph> const vps =
-		getVisibleParagraphs(*view.get());
-
-	InsetList::const_iterator it  = insets.begin();
-	InsetList::const_iterator end = insets.end();
-
-	it = std::find_if(it, end, FindVisibleInset(vps));
-
-	// One of the insets is visible, so start loading the image.
-	if (it != end)
-		cached_item_->startLoading();
+	LoaderQueue::get().touch(cached_item_);
 }
 
 

src/graphics/GraphicsSupport.C

@@ -1,100 +0,0 @@
-/**
- *  \file GraphicsSupport.C
- * This file is part of LyX, the document processor.
- * Licence details can be found in the file COPYING.
- *
- * \author Angus Leeming
- *
- * Full author contact details are available in file CREDITS
- */
-
-#include <config.h>
-
-#include "GraphicsSupport.h"
-
-#include "BufferView.h"
-#include "lyxtext.h"
-#include "lyxrow.h"
-#include "paragraph.h"
-#include "frontends/Painter.h"
-
-
-typedef std::list<VisibleParagraph> VPList;
-
-
-VPList const getVisibleParagraphs(BufferView const & bv)
-{
-	// top_y is not const because it's reset by getRowNearY.
-	int top_y = bv.text->first_y;
-	Row const * row = bv.text->getRowNearY(top_y);
-
-	int const bv_height = bv.painter().paperHeight();
-
-	VPList vps;
-	Row const * last_row = 0;
-
-	for (int height = 0; row && height < bv_height; row = row->next()) {
-		height += row->height();
-
-		if (vps.empty() || vps.back().par != row->par()) {
-			vps.push_back(VisibleParagraph(row->par(),
-						       row->pos(),
-						       row->par()->size()));
-		}
-
-		last_row = row;
-	}
-
-	// If the end of the final paragraph is not visble,
-	// update vps.back().end
-	if (last_row && last_row->next() &&
-	    last_row->par() == last_row->next()->par()) {
-		vps.back().end = last_row->next()->pos();
-	}
-
-	return vps;
-}
-
-
-namespace {
-
-struct InsetVisibleInParagraph {
-	InsetVisibleInParagraph(Inset const & inset) : inset_(inset) {}
-	bool operator()(VisibleParagraph const & vp)
-	{
-		Paragraph * par = vp.par;
-		InsetList::iterator it  = par->insetlist.begin();
-		InsetList::iterator end = par->insetlist.end();
-
-		// Can't refactor this as a functor because we rely on the
-		// inset_iterator member function getPos().
-		for (; it != end; ++it) {
-			lyx::pos_type const pos = it.getPos();
-			if (pos >= vp.start && pos <= vp.end) {
-				if (it.getInset() == &inset_ ||
-				    it.getInset()->getInsetFromID(inset_.id()) != 0)
-					return true;
-			}
-		}
-		return false;
-	}
-
-private:
-	Inset const & inset_;
-};
-
-} // namespace anon
-
-
-bool isInsetVisible(Inset const & inset, VPList const & vps)
-{
-	if (vps.empty())
-		return false;
-
-	VPList::const_iterator it  = vps.begin();
-	VPList::const_iterator end = vps.end();
-
-	it = std::find_if(it, end, InsetVisibleInParagraph(inset));
-
-	return it != end;
-}

src/graphics/GraphicsSupport.h

@@ -1,48 +0,0 @@
-// -*- C++ -*-
-/**
- *  \file GraphicsSupport.h
- * This file is part of LyX, the document processor.
- * Licence details can be found in the file COPYING.
- *
- * \author Angus Leeming
- *
- * Full author contact details are available in file CREDITS
- */
-
-#ifndef GRAPHICSSUPPORT_H
-#define GRAPHICSSUPPORT_H
-
-#include "support/types.h"
-#include <list>
-
-class BufferView;
-class Inset;
-class Paragraph;
-
-/** A Paragraph * together with delimiters for the start and end positions
-    of visibility.
- */
-struct VisibleParagraph {
-	///
-	VisibleParagraph() : par(0), start(0), end(0) {}
-	///
-	VisibleParagraph(Paragraph * p, lyx::pos_type s, lyx::pos_type e)
-		: par(p), start(s), end(e) {}
-	///
-	Paragraph * par;
-	///
-	lyx::pos_type start;
-	///
-	lyx::pos_type end;
-};
-
-
-/// Returns a list of all Paragraphs currently visible in bv.
-std::list<VisibleParagraph> const getVisibleParagraphs(BufferView const & bv);
-
-/** Given this data, check whether inset lies within it and is, therefore,
- *  visible.
- */
-bool isInsetVisible(Inset const & inset, std::list<VisibleParagraph> const &);
-
-#endif // GRAPHICSSUPPORT_H

src/graphics/LoaderQueue.C

@@ -0,0 +1,116 @@
+/**
+ * \file LoaderQueue.C
+ * This file is part of LyX, the document processor.
+ * Licence details can be found in the file COPYING.
+ *
+ * \author Alfredo Braunstein
+ *
+ * Full author contact details are available in file CREDITS
+ */
+
+#include "LoaderQueue.h"
+
+#include "debug.h"
+
+#include <boost/bind.hpp>
+
+using std::endl;
+using std::list;
+
+
+namespace grfx {
+
+
+LoaderQueue & LoaderQueue::get()
+{
+	static LoaderQueue singleton;
+	return singleton;
+}
+
+
+void LoaderQueue::loadNext() 
+{
+	emptyBucket();
+	lyxerr[Debug::GRAPHICS] << "LoaderQueue: "
+				<< cache_queue_.size()
+				<< " items in the queue" << endl; 
+	int counter = 10;
+	while (cache_queue_.size() && counter--) {
+		if(cache_queue_.front()->status() == WaitingToLoad)
+			cache_queue_.front()->startLoading();
+		cache_set_.erase(cache_queue_.front());
+		cache_queue_.pop_front();
+	}
+	if (cache_queue_.size() || bucket_.size()) {
+		startLoader();
+	} else {
+		stopLoader();
+	}
+}
+
+
+LoaderQueue::LoaderQueue() : timer(100, Timeout::ONETIME), 
+			     running_(false)
+{
+	timer.timeout.connect(boost::bind(&LoaderQueue::loadNext, this));
+}
+
+	
+void LoaderQueue::emptyBucket()
+{
+	lyxerr[Debug::GRAPHICS] << "LoaderQueue: emptying bucket" 
+				<< endl;
+	while (! bucket_.empty()) {
+		addToQueue(bucket_.front());
+		bucket_.pop();
+	}
+}
+
+
+void LoaderQueue::startLoader()
+{
+	lyxerr[Debug::GRAPHICS] << "LoaderQueue: waking up" << endl;
+	running_ = true ;
+	timer.start();
+}
+
+
+void LoaderQueue::stopLoader()
+{
+	timer.stop();
+	running_ = false ;
+	lyxerr[Debug::GRAPHICS] << "LoaderQueue: I'm going to sleep" << endl;
+}
+
+
+bool LoaderQueue::running() const
+{
+	return running_ ;
+}
+
+
+void LoaderQueue::touch(Cache::ItemPtr const & item)
+{
+	if (! running_)
+		startLoader();
+	bucket_.push(item);
+}
+
+
+void LoaderQueue::addToQueue(Cache::ItemPtr const & item)
+{
+	if (! cache_set_.insert(item).second) {
+		list<Cache::ItemPtr>::iterator 
+			it = cache_queue_.begin();
+		list<Cache::ItemPtr>::iterator 
+			end = cache_queue_.end();
+		
+		it = std::find(it, end, item);
+		if (it != end)
+			cache_queue_.erase(it);
+	} 
+	cache_queue_.push_front(item);
+}
+
+
+} // namespace grfx

src/graphics/LoaderQueue.h

@@ -0,0 +1,69 @@
+// -*- C++ -*-
+/**
+ *  \file LoaderQueue.h
+ * This file is part of LyX, the document processor.
+ * Licence details can be found in the file COPYING.
+ *
+ *  \author Alfredo Braunstein
+ *
+ * Full author contact details are available in file CREDITS. 
+ *
+ * This implements a threaded service queue which loads images on background.
+ * In order to request an image loading you call touch() with the pointer to
+ * the cached image. Then it will try to satisfy the request as soon as 
+ * posible (that's it: after finishing an eventual loading on progress)
+ * touch() returns inmediately, in order not tu disrupt the flow of the main
+ * thread.
+ * The service thread is the method loadNext(). It's actually not a thread,
+ * but implemented with a timer that comes back every x msec.
+ */
+
+#ifndef LOADERQUEUE_H
+#define LOADERQUEUE_H
+
+#include "GraphicsCache.h"
+#include "GraphicsCacheItem.h"
+
+#include "frontends/Timeout.h"
+
+#include <set>
+#include <queue>
+
+namespace grfx {
+
+class LoaderQueue {
+public:
+	//use this to request a loading
+	void touch(Cache::ItemPtr const & item);
+	//query if the clock is ticking
+	bool running() const;
+	//get the and only instance of the class
+	static LoaderQueue & get();
+private:
+	//this class is a singleton class... use LoaderQueue::get() instead
+	LoaderQueue();
+	//in-progress loading queue (elements are unique here) 
+	std::list<Cache::ItemPtr> cache_queue_;
+	//makes faster the insertion of new elements
+	std::set<Cache::ItemPtr> cache_set_;
+	//newly touched element go here, loadNext move them to cache_queue_
+	std::queue<Cache::ItemPtr> bucket_;
+	//
+	Timeout timer;
+	//
+	bool running_;
+	//moves bucket_ to cache_queue_
+	void emptyBucket();
+	//adds or reprioritizes one element in cache_queue_
+	void addToQueue(Cache::ItemPtr const & item);
+	//this is the 'threaded' method, that does the loading in background
+	void loadNext();
+	//
+	void startLoader();
+	//
+	void stopLoader();
+};
+
+} // namespace grfx
+
+#endif // LOADERQUEUE_H

src/graphics/Makefile.am

@@ -17,8 +17,8 @@ libgraphics_la_SOURCES = \
 	GraphicsLoader.C \
 	GraphicsParams.C \
 	GraphicsParams.h \
-	GraphicsSupport.h \
-	GraphicsSupport.C \
+	LoaderQueue.h \
+	LoaderQueue.C \
 	GraphicsTypes.h \
 	GraphicsTypes.C \
 	PreviewImage.h \