I'm fiddling a little with the graphics loader, and I started to implement a
pseudo threaded version of it (patch attached).
It works as follows: there is this LoaderQueue class (I think every
BufferView should have one, right now is simply a global class), which
implements a queue with a twist:
1) Elements are unique
2) Reinserting an element reprioritizes it to the top
I.e. it sort of works like the 'touch' command.
Right now it's implemented as a queue + a set, so it's O(ln n) for the
'first time insert' case, and O(n) for the 'already have it' case.
I plan to make it O(ln n) always.
His loadNext method should run in an independent thread, right now it runs
with a timer that comes back every .1 seconds. I've put a minimal locking
mecanism. Should be trivial to convert to a real thread once boost.threads
is installed on the LyX tree.
This LoaderQueue is called from Loader::startLoading, i.e. from there we
'touch' the graphic. Nothing is really loaded on screen yet. The real
loading is done on the loadNext method (the 'threaded' one).
It works pretty nicely I think (except for the O(n) thingie and some other
details). And the patch is very minimal.
I know that the coding style is broken, please correct me without mercy.
Anyway of course it's not to be applied, It's only a proof of concept.
I have some questions about when these Loadings are called, so if someone
thinks that this is not a complete trash then I go on and ask them.
Please be nice.
Regards, Alfredo
? patch.diff
Index: GraphicsLoader.C
===================================================================
RCS file: /cvs/lyx/lyx-devel/src/graphics/GraphicsLoader.C,v
retrieving revision 1.12
diff -u -r1.12 GraphicsLoader.C
--- GraphicsLoader.C 2003/02/13 16:53:00 1.12
+++ GraphicsLoader.C 2003/02/19 08:11:58
@@ -28,9 +28,60 @@
#include <boost/signals/trackable.hpp>
#include <list>
+#include <set>
namespace grfx {
+class LoaderQueue {
+public:
+ LoaderQueue():timer( 100 , Timeout::ONETIME )
+ {
+ timer.timeout.connect( boost::bind( &LoaderQueue::loadNext, this));
+ locked = false;
+ timer.start();
+ }
+ void touch(Cache::ItemPtr item) {
+
+ if(locked)
+ return;
+
+ locked = true;
+
+ 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 );
+ cache_queue_.erase( it );
+ }
+ cache_queue_.push_front( item );
+ locked = false;
+ }
+private:
+ bool locked;
+ std::list<Cache::ItemPtr> cache_queue_;
+ std::set<Cache::ItemPtr> cache_set_;
+ Timeout timer;
+ void loadNext() {
+ if(locked)
+ return;
+ locked = true;
+ int counter = 10;
+ while (cache_queue_.size() && --counter) {
+ cout << cache_queue_.size()
+ << " items in the queue" << endl;
+ cache_queue_.front()->startLoading();
+ cache_set_.erase(cache_queue_.front());
+ cache_queue_.pop_front();
+ }
+ locked = false;
+ timer.start();
+ };
+} LQ;
+
struct Loader::Impl : boost::signals::trackable {
///
Impl(Params const &);
@@ -66,8 +117,6 @@
///
Params params_;
- ///
- Timeout timer;
// Multiple Insets can share the same image
typedef std::list<Inset const *> InsetList;
///
@@ -196,10 +245,8 @@
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));
}
@@ -266,7 +313,6 @@
signal_();
}
-
void Loader::Impl::createPixmap()
{
if (!cached_item_.get() ||
@@ -293,7 +339,7 @@
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();
@@ -302,8 +348,7 @@
if (it == end)
insets.push_back(&inset);
view = bv.owner()->view();
-
- timer.start();
+ LQ.touch(cached_item_);
}
Index: GraphicsSupport.C
===================================================================
RCS file: /cvs/lyx/lyx-devel/src/graphics/GraphicsSupport.C,v
retrieving revision 1.7
diff -u -r1.7 GraphicsSupport.C
--- GraphicsSupport.C 2003/02/13 16:53:00 1.7
+++ GraphicsSupport.C 2003/02/19 08:11:58
@@ -33,7 +33,7 @@
VPList vps;
Row const * last_row = 0;
- for (int height = 0; row && height < bv_height; row = row->next()) {
+ for (int height = 0; row && height < 2 *bv_height; row = row->next()) {
height += row->height();
if (vps.empty() || vps.back().par != row->par()) {
Index: PreviewImage.C
===================================================================
RCS file: /cvs/lyx/lyx-devel/src/graphics/PreviewImage.C,v
retrieving revision 1.11
diff -u -r1.11 PreviewImage.C
--- PreviewImage.C 2003/02/13 16:53:00 1.11
+++ PreviewImage.C 2003/02/19 08:11:58
@@ -33,7 +33,6 @@
Image const * image(Inset const &, BufferView const &);
///
void statusChanged();
-
///
PreviewImage const & parent_;
///
