Addition of locking cache for display list in winRT library

9 files changed, 199 insertions, 76 deletions

diff --git a/winrt/mupdf_cpp/MainPage.xaml.cpp b/winrt/mupdf_cpp/MainPage.xaml.cpp
index e700a444..4c1095bf 100644
--- a/winrt/mupdf_cpp/MainPage.xaml.cpp
+++ b/winrt/mupdf_cpp/MainPage.xaml.cpp
@@ -642,7 +642,7 @@ void mupdf_cpp::MainPage::InitialRender()
 			Point ras_size = ComputePageSize(spatial_info, k);
 
 			auto render_task =
-				create_task(mu_doc->RenderPageAsync(k, ras_size.X, ras_size.Y, false));
+				create_task(mu_doc->RenderPageAsync(k, ras_size.X, ras_size.Y, true));
 
 			render_task.then([this, k, ras_size] (InMemoryRandomAccessStream^ ras)
 			{
@@ -689,7 +689,7 @@ void mupdf_cpp::MainPage::RenderRange(int curr_page)
 			{
 				Point ras_size = ComputePageSize(spatial_info, k);
 				auto render_task =
-					create_task(mu_doc->RenderPageAsync(k, ras_size.X, ras_size.Y, false));
+					create_task(mu_doc->RenderPageAsync(k, ras_size.X, ras_size.Y, true));
 
 				render_task.then([this, k, ras_size] (InMemoryRandomAccessStream^ ras)
 				{
@@ -750,7 +750,7 @@ void mupdf_cpp::MainPage::Slider_ValueChanged(Platform::Object^ sender, Windows:
 			spatial_info_t spatial_info = InitSpatial(1);
 			Point ras_size = ComputePageSize(spatial_info, newValue);
 			auto render_task =
-				create_task(mu_doc->RenderPageAsync(newValue, ras_size.X, ras_size.Y, false));
+				create_task(mu_doc->RenderPageAsync(newValue, ras_size.X, ras_size.Y, true));
 
 			render_task.then([this, newValue, ras_size] (InMemoryRandomAccessStream^ ras)
 			{
@@ -1345,20 +1345,12 @@ void mupdf_cpp::MainPage::ScrollChanged(Platform::Object^ sender,
 		Point ras_size = ComputePageSize(spatial_info, page);
 
 		/* Go ahead and create display list if we dont have one for this page */
-		auto ui = task_continuation_context::use_current();
-		auto display_task = create_task(mu_doc->CreateDisplayList(page));
-		display_task.then([this, page, ras_size, ui] (int code)
+		auto render_task =
+			create_task(mu_doc->RenderPageAsync(page, ras_size.X, ras_size.Y, true));
+		render_task.then([this, page, ras_size] (InMemoryRandomAccessStream^ ras)
 		{
-			if (code == S_ISOK)
-			{
-				auto render_task =
-					create_task(mu_doc->RenderPageAsync(page, ras_size.X, ras_size.Y, true));
-				render_task.then([this, page, ras_size] (InMemoryRandomAccessStream^ ras)
-				{
-					ReplaceImage(page, ras, ras_size);
-				}, ui);
-			}
-		});
+			ReplaceImage(page, ras, ras_size);
+		}, task_continuation_context::use_current());
 	}
 }
 
diff --git a/winrt/mupdfwinrt/Cache.cpp b/winrt/mupdfwinrt/Cache.cpp
new file mode 100644
index 00000000..e1e68241
--- /dev/null
+++ b/winrt/mupdfwinrt/Cache.cpp
@@ -0,0 +1,112 @@
+#include "pch.h"
+#include "Cache.h"
+
+Cache::Cache(void)
+{
+	this->size = 0;
+	this->head = NULL;
+	this->tail = NULL;
+}
+
+Cache::~Cache(void)
+{
+}
+
+void Cache::Empty(fz_context *mu_ctx)
+{
+	cache_entry_t *curr_entry = this->head;
+
+	while (curr_entry != NULL)
+	{
+		cache_entry_t *old_entry = curr_entry;
+		curr_entry = old_entry->next;
+		fz_drop_display_list(mu_ctx, old_entry->dlist);
+		delete old_entry;
+	}
+	this->size = 0;
+	this->head = NULL;
+	this->tail = NULL;
+}
+
+void Cache::AddEntry(int value, fz_display_list *dlist, fz_context *mu_ctx)
+{
+	std::lock_guard<std::mutex> lock(cache_lock);
+
+	/* If full, then delete the tail */
+	if (size >= MAX_DISPLAY_CACHE_SIZE)
+	{
+		cache_entry_t *curr_entry = this->tail;
+		cache_entry_t *prev_entry = curr_entry->prev;
+
+		if (prev_entry != NULL)
+			prev_entry->next = NULL;
+		else
+			head = NULL;
+
+		tail = prev_entry;
+
+		/* Decrement the caches rc of this list */
+		fz_drop_display_list(mu_ctx, curr_entry->dlist);
+		delete curr_entry;
+		size--;
+	}
+
+	/* Make a new entry and stick at head */
+	cache_entry_t *new_entry = new cache_entry_t;
+
+	new_entry->dlist = dlist;
+	new_entry->index = value;
+	new_entry->prev = NULL;
+	if (head == NULL)
+	{
+		new_entry->next = NULL;
+		head = new_entry;
+		tail = new_entry;
+	}
+	else
+	{
+		new_entry->next = head;
+		head->prev = new_entry;
+		head = new_entry;
+	}
+	size++;
+	/* We are going to use this item now */
+	fz_keep_display_list(mu_ctx, new_entry->dlist);
+}
+
+fz_display_list* Cache::UseEntry(int value, fz_context *mu_ctx)
+{
+	std::lock_guard<std::mutex> lock(cache_lock);
+	cache_entry_t *curr_entry = this->head;
+
+	while (curr_entry != NULL)
+	{
+		if (curr_entry->index == value)
+			break;
+		curr_entry = curr_entry->next;
+	}
+	if (curr_entry != NULL)
+	{
+		fz_keep_display_list(mu_ctx, curr_entry->dlist);
+		/* Move this to the front */
+		if (curr_entry != head)
+		{
+			cache_entry_t *prev_entry = curr_entry->prev;
+			cache_entry_t *next_entry = curr_entry->next;
+			prev_entry->next = next_entry;
+
+			if (next_entry != NULL)
+				next_entry->prev = prev_entry;
+			else
+				tail = prev_entry;
+
+			curr_entry->prev = NULL;
+			curr_entry->next = head;
+			head->prev = curr_entry;
+			head = curr_entry;
+		}
+		return curr_entry->dlist;
+	}
+	else
+		return NULL;
+}
diff --git a/winrt/mupdfwinrt/Cache.h b/winrt/mupdfwinrt/Cache.h
new file mode 100644
index 00000000..f8dd8ecb
--- /dev/null
+++ b/winrt/mupdfwinrt/Cache.h
@@ -0,0 +1,37 @@
+#pragma once
+
+#include <mutex>
+extern "C" {
+	#include "fitz.h"
+	#include "fitz-internal.h"
+	#include "muxps.h"
+	#include "mupdf.h"
+}
+
+#define MAX_DISPLAY_CACHE_SIZE 3
+
+typedef struct cache_entry_s cache_entry_t;
+
+struct cache_entry_s
+{
+	fz_display_list *dlist;
+	cache_entry_t *next;
+	cache_entry_t *prev;
+	int index;
+};
+
+class Cache
+{
+private:
+	int size;
+	cache_entry_t *head;
+	cache_entry_t *tail;
+	std::mutex cache_lock;
+
+public:
+	Cache(void);
+	~Cache(void);
+	fz_display_list* UseEntry(int value, fz_context *mu_ctx);
+	void AddEntry(int value, fz_display_list *dlist, fz_context *mu_ctx);
+	void Empty(fz_context *mu_ctx);
+};
diff --git a/winrt/mupdfwinrt/muctx.cpp b/winrt/mupdfwinrt/muctx.cpp
index 40849fb9..5db701aa 100644
--- a/winrt/mupdfwinrt/muctx.cpp
+++ b/winrt/mupdfwinrt/muctx.cpp
@@ -131,11 +131,10 @@ status_t muctx::InitializeContext()
 /* Initializer */
 muctx::muctx(void)
 {
-	this->mu_ctx = NULL;
-	this->mu_doc = NULL;
-	this->mu_outline = NULL;
-	this->mu_dlist = NULL;
-	this->dlist_pagenum = -1;
+	mu_ctx = NULL;
+	mu_doc = NULL;
+	mu_outline = NULL;
+	display_list_cache = new Cache();
 }
 
 /* Destructor */
@@ -143,14 +142,14 @@ muctx::~muctx(void)
 {
 	fz_free_outline(mu_ctx, mu_outline);
 	fz_close_document(mu_doc);
-	fz_free_display_list(mu_ctx, mu_dlist);
+	display_list_cache->Empty(mu_ctx);
 	fz_free_context(mu_ctx);
 
-	this->mu_ctx = NULL;
-	this->mu_doc = NULL;
-	this->mu_outline = NULL;
-	this->mu_dlist = NULL;
-	this->dlist_pagenum = -1;
+	mu_ctx = NULL;
+	mu_doc = NULL;
+	mu_outline = NULL;
+	delete display_list_cache;
+	display_list_cache = NULL;
 }
 
 /* Set up the stream access */
@@ -406,7 +405,7 @@ int muctx::GetLinks(int page_num, sh_vector_link links_vec)
 	return num_links;
 }
 
-status_t muctx::CreateDisplayList(int page_num)
+fz_display_list * muctx::CreateDisplayList(int page_num)
 {
 	fz_context *ctx_clone = NULL;
 	fz_device *dev = NULL;
@@ -414,20 +413,24 @@ status_t muctx::CreateDisplayList(int page_num)
 
 	ctx_clone = fz_clone_context(mu_ctx);
 
+	/* First see if we have this one in the cache */
+	fz_display_list *dlist = display_list_cache->UseEntry(page_num, ctx_clone);
+	if (dlist != NULL)
+		return dlist;
+
+	/* Apparently not, lets go ahead and create and add to cache */
 	fz_var(dev);
 	fz_var(page);
 	fz_try(ctx_clone)
 	{
 		page = fz_load_page(mu_doc, page_num);
 
-		/* Free current list if we have one */
-		if (mu_dlist != NULL)
-			fz_free_display_list(ctx_clone, mu_dlist);
-
 		/* Create a new list */
-		mu_dlist = fz_new_display_list(ctx_clone);
-		dev = fz_new_list_device(ctx_clone, mu_dlist);
+		dlist = fz_new_display_list(ctx_clone);
+		dev = fz_new_list_device(ctx_clone, dlist);
 		fz_run_page_contents(mu_doc, page, dev, &fz_identity, NULL);
+		/* Add it to the cache and set that it is in use */
+		display_list_cache->AddEntry(page_num, dlist, ctx_clone);
 	}
 	fz_always(ctx_clone)
 	{
@@ -437,16 +440,9 @@ status_t muctx::CreateDisplayList(int page_num)
 	fz_catch(ctx_clone)
 	{
 		fz_free_context(ctx_clone);
-		dlist_pagenum = -1;
-		return E_FAILURE;
+		return NULL;
 	}
-	dlist_pagenum = page_num;
-	return S_ISOK;
-}
-
-int muctx::GetDisplayListPage(void)
-{
-	return dlist_pagenum;
+	return dlist;
 }
 
 /* Render page_num to size width by height into bmp_data buffer */
@@ -459,15 +455,18 @@ status_t muctx::RenderPage(int page_num, int width, int height,
 	fz_matrix ctm, *pctm = &ctm;
 	Point page_size;
 	fz_context *ctx_clone = NULL;
+	fz_display_list *dlist = NULL;
 
-	if (mu_dlist == NULL && use_dlist)
-		return E_FAILURE;
+	if (use_dlist)
+		if ((dlist = CreateDisplayList(page_num)) == NULL)
+			return E_FAILURE;
 
 	ctx_clone = fz_clone_context(mu_ctx);
 
 	fz_var(dev);
 	fz_var(pix);
 	fz_var(page);
+
 	fz_try(ctx_clone)
 	{
 		page = fz_load_page(mu_doc, page_num);
@@ -482,7 +481,7 @@ status_t muctx::RenderPage(int page_num, int width, int height,
 		fz_clear_pixmap_with_value(ctx_clone, pix, 255);
 		dev = fz_new_draw_device(ctx_clone, pix);
 		if (use_dlist)
-			fz_run_display_list(mu_dlist, dev, pctm, NULL, NULL);
+			fz_run_display_list(dlist, dev, pctm, NULL, NULL);
 		else
 			fz_run_page(mu_doc, page, dev, pctm, NULL);
 	}
@@ -491,6 +490,9 @@ status_t muctx::RenderPage(int page_num, int width, int height,
 		fz_free_device(dev);
 		fz_drop_pixmap(ctx_clone, pix);
 		fz_free_page(mu_doc, page);
+		if (use_dlist)
+			fz_drop_display_list(ctx_clone, dlist);
+
 	}
 	fz_catch(ctx_clone)
 	{
diff --git a/winrt/mupdfwinrt/muctx.h b/winrt/mupdfwinrt/muctx.h
index d22009a0..7c984b91 100644
--- a/winrt/mupdfwinrt/muctx.h
+++ b/winrt/mupdfwinrt/muctx.h
@@ -6,6 +6,7 @@
 #include <windows.h>
 #include <mutex>
 #include "utils.h"
+#include "Cache.h"
 
 extern "C" {
 	#include "fitz.h"
@@ -80,12 +81,12 @@ private:
 	fz_locks_context mu_locks;
 	fz_context *mu_ctx;
 	fz_document *mu_doc;
-	fz_display_list *mu_dlist;
-	int dlist_pagenum;
 	fz_outline *mu_outline;
 	fz_rect mu_hit_bbox[MAX_SEARCH];
 	void FlattenOutline(fz_outline *outline, int level,
-				sh_vector_content contents_vec);
+						sh_vector_content contents_vec);
+	Cache *display_list_cache;
+	fz_display_list* CreateDisplayList(int page_num);
 
 public:
 	muctx(void);
@@ -94,9 +95,8 @@ public:
 	status_t InitializeStream(IRandomAccessStream^ readStream, char *ext);
 	int GetPageCount();
 	status_t InitializeContext();
-	status_t RenderPage(int page_num, int width, int height, unsigned char *bmp_data, bool use_dlist);
-	status_t CreateDisplayList(int page_num);
-	int GetDisplayListPage(void);
+	status_t RenderPage(int page_num, int width, int height, unsigned char *bmp_data,
+						bool use_dlist);
 	Point MeasurePage(int page_num);
 	Point MeasurePage(fz_page *page);
 	int GetLinks(int page_num, sh_vector_link links_vec);
diff --git a/winrt/mupdfwinrt/mudocument.cpp b/winrt/mupdfwinrt/mudocument.cpp
index 8688d520..b33be118 100644
--- a/winrt/mupdfwinrt/mudocument.cpp
+++ b/winrt/mupdfwinrt/mudocument.cpp
@@ -162,28 +162,6 @@ Windows::Foundation::IAsyncOperationWithProgress<int, double>^
 	});
 }
 
-/* Create the display list for this page */
-Windows::Foundation::IAsyncOperation<int>^ mudocument::CreateDisplayList(int page_num)
-{
-	return create_async([this, page_num](cancellation_token ct) -> int
-	{
-		if (mu_object.GetDisplayListPage() == page_num)
-			return S_ISOK;
-		std::lock_guard<std::mutex> lock(mutex_lock);
-		status_t code = mu_object.CreateDisplayList(page_num);
-		if (code != S_ISOK)
-		{
-			throw ref new FailureException("Display List Creation Failed");
-		}
-		return code;
-	});
-}
-
-int mudocument::GetDisplayListPage(void)
-{
-	return mu_object.GetDisplayListPage();
-}
-
 /* Pack the page into a bmp stream */
 Windows::Foundation::IAsyncOperation<InMemoryRandomAccessStream^>^
 	mudocument::RenderPageAsync(int page_num, int width, int height, bool use_dlist)
diff --git a/winrt/mupdfwinrt/mudocument.h b/winrt/mupdfwinrt/mudocument.h
index d90d2c9a..c4bc0b4e 100644
--- a/winrt/mupdfwinrt/mudocument.h
+++ b/winrt/mupdfwinrt/mudocument.h
@@ -36,7 +36,6 @@ namespace mupdfwinrt
 			Windows::Foundation::IAsyncOperation<int>^ OpenFileAsync(StorageFile^ file);
 			int GetNumPages(void);
 			Point GetPageSize(int page_num);
-			Windows::Foundation::IAsyncOperation<int>^ mudocument::CreateDisplayList(int page_num);
 			Windows::Foundation::IAsyncOperation<InMemoryRandomAccessStream^>^
 				RenderPageAsync(int page_num, int width, int height, bool use_dlist);
 			Windows::Foundation::IAsyncOperationWithProgress<int, double>^
@@ -48,7 +47,6 @@ namespace mupdfwinrt
 			int ComputeContents(void);
 			ContentItem^ GetContent(int k);
 			int ComputeLinks(int page_num);
-			int GetDisplayListPage(void);
 			Links^ GetLink(int k);
 			bool RequiresPassword();
 			bool ApplyPassword(String^ password);
diff --git a/winrt/mupdfwinrt/mupdfwinrt.vcxproj b/winrt/mupdfwinrt/mupdfwinrt.vcxproj
index 2b63addb..2510491a 100644
--- a/winrt/mupdfwinrt/mupdfwinrt.vcxproj
+++ b/winrt/mupdfwinrt/mupdfwinrt.vcxproj
@@ -217,6 +217,7 @@
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
+    <ClInclude Include="Cache.h" />
     <ClInclude Include="Links.h" />
     <ClInclude Include="ContentItem.h" />
     <ClInclude Include="muctx.h" />
@@ -225,6 +226,7 @@
     <ClInclude Include="utils.h" />
   </ItemGroup>
   <ItemGroup>
+    <ClCompile Include="Cache.cpp" />
     <ClCompile Include="Links.cpp" />
     <ClCompile Include="ContentItem.cpp" />
     <ClCompile Include="muctx.cpp" />
diff --git a/winrt/mupdfwinrt/mupdfwinrt.vcxproj.filters b/winrt/mupdfwinrt/mupdfwinrt.vcxproj.filters
index 23e52055..5c98d5ba 100644
--- a/winrt/mupdfwinrt/mupdfwinrt.vcxproj.filters
+++ b/winrt/mupdfwinrt/mupdfwinrt.vcxproj.filters
@@ -13,6 +13,7 @@
     <ClCompile Include="Links.cpp" />
     <ClCompile Include="ContentItem.cpp" />
     <ClCompile Include="utils.cpp" />
+    <ClCompile Include="Cache.cpp" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="pch.h" />
@@ -21,5 +22,6 @@
     <ClInclude Include="Links.h" />
     <ClInclude Include="utils.h" />
     <ClInclude Include="ContentItem.h" />
+    <ClInclude Include="Cache.h" />
   </ItemGroup>
 </Project>
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