Invalidate textures cached by SW path renderer when paths go away

Bug: skia:
Change-Id: Icfc2f1bd57c0cf7be54469b6d86cbd436b59155d
Reviewed-on: https://skia-review.googlesource.com/51201
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

src/gpu/GrSoftwarePathRenderer.cpp

@@ -200,6 +200,18 @@ private:
     GrAA fAA;
 };
 
+// When the SkPathRef genID changes, invalidate a corresponding GrResource described by key.
+class PathInvalidator : public SkPathRef::GenIDChangeListener {
+public:
+    explicit PathInvalidator(const GrUniqueKey& key) : fMsg(key) {}
+private:
+    GrUniqueKeyInvalidatedMessage fMsg;
+
+    void onChange() override {
+        SkMessageBus<GrUniqueKeyInvalidatedMessage>::Post(fMsg);
+    }
+};
+
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -344,6 +356,7 @@ bool GrSoftwarePathRenderer::onDrawPath(const DrawPathArgs& args) {
         if (useCache) {
             SkASSERT(proxy->origin() == kTopLeft_GrSurfaceOrigin);
             fResourceProvider->assignUniqueKeyToProxy(maskKey, proxy.get());
+            args.fShape->addGenIDChangeListener(new PathInvalidator(maskKey));
         }
     }
     if (inverseFilled) {

tests/PathRendererCacheTests.cpp

@@ -14,6 +14,7 @@
 #include "GrContext.h"
 #include "GrContextPriv.h"
 #include "GrResourceCache.h"
+#include "GrSoftwarePathRenderer.h"
 #include "effects/GrPorterDuffXferProcessor.h"
 #include "ops/GrTessellatingPathRenderer.h"
 
@@ -31,8 +32,8 @@ static void draw_path(GrContext* ctx,
                       GrRenderTargetContext* renderTargetContext,
                       const SkPath& path,
                       GrPathRenderer* pr,
-                      GrAAType aaType = GrAAType::kNone,
-                      GrStyle style = GrStyle(SkStrokeRec::kFill_InitStyle)) {
+                      GrAAType aaType,
+                      const GrStyle& style) {
     GrPaint paint;
     paint.setXPFactory(GrPorterDuffXPFactory::Get(SkBlendMode::kSrc));
 
@@ -57,14 +58,23 @@ static void draw_path(GrContext* ctx,
     pr->drawPath(args);
 }
 
+static bool cache_non_scratch_resources_equals(GrResourceCache* cache, int expected) {
+#if GR_CACHE_STATS
+    GrResourceCache::Stats stats;
+    cache->getStats(&stats);
+    return (stats.fTotal - stats.fScratch) == expected;
+#else
+    return true;
+#endif
+}
+
 static void test_path(skiatest::Reporter* reporter,
                       std::function<SkPath(void)> createPath,
-                      GrPathRenderer* pathRenderer,
-                      int expectedResources = 1,
+                      std::function<GrPathRenderer*(GrContext*)> createPathRenderer,
                       GrAAType aaType = GrAAType::kNone,
                       GrStyle style = GrStyle(SkStrokeRec::kFill_InitStyle)) {
     sk_sp<GrContext> ctx = GrContext::MakeMock(nullptr);
-    ctx->setResourceCacheLimits(100, 10000);
+    ctx->setResourceCacheLimits(100, 100000);
     GrResourceCache* cache = ctx->getResourceCache();
 
     sk_sp<GrRenderTargetContext> rtc(ctx->makeDeferredRenderTargetContext(
@@ -74,40 +84,61 @@ static void test_path(skiatest::Reporter* reporter,
         return;
     }
 
+    sk_sp<GrPathRenderer> pathRenderer(createPathRenderer(ctx.get()));
     SkPath path = createPath();
 
     // Initially, cache only has the render target context
-    REPORTER_ASSERT(reporter, 1 == cache->getResourceCount());
+    REPORTER_ASSERT(reporter, cache_non_scratch_resources_equals(cache, 0));
 
     // Draw the path, check that new resource count matches expectations
-    draw_path(ctx.get(), rtc.get(), path, pathRenderer);
+    draw_path(ctx.get(), rtc.get(), path, pathRenderer.get(), aaType, style);
     ctx->flush();
-    REPORTER_ASSERT(reporter, (1 + expectedResources) == cache->getResourceCount());
+    REPORTER_ASSERT(reporter, cache_non_scratch_resources_equals(cache, 1));
 
     // Nothing should be purgeable yet
     cache->purgeAsNeeded();
-    REPORTER_ASSERT(reporter, (1 + expectedResources) == cache->getResourceCount());
+    REPORTER_ASSERT(reporter, cache_non_scratch_resources_equals(cache, 1));
 
     // Reset the path to change the GenID, which should invalidate any resources in the cache
     path.reset();
     cache->purgeAsNeeded();
-    REPORTER_ASSERT(reporter, 1 == cache->getResourceCount());
+    REPORTER_ASSERT(reporter, cache_non_scratch_resources_equals(cache, 0));
 }
 
 // Test that deleting the original path invalidates the VBs cached by the tessellating path renderer
 DEF_GPUTEST(TessellatingPathRendererCacheTest, reporter, factory) {
-    GrTessellatingPathRenderer tess;
+    auto createPR = [](GrContext*) {
+        return new GrTessellatingPathRenderer();
+    };
 
     // Tessellating path renderer stores vertex buffers in the cache (for non-AA paths)
-    test_path(reporter, create_concave_path, &tess);
+    test_path(reporter, create_concave_path, createPR);
 
-    // Test with a shape that applies. This needs to attach the invalidation logic to the original
-    // path, not the modified path produced by the style.
+    // Test with a style that alters the path geometry. This needs to attach the invalidation logic
+    // to the original path, not the modified path produced by the style.
     SkPaint paint;
     paint.setStyle(SkPaint::kStroke_Style);
     paint.setStrokeWidth(1);
     GrStyle style(paint);
-    test_path(reporter, create_concave_path, &tess, 1, GrAAType::kNone, style);
+    test_path(reporter, create_concave_path, createPR, GrAAType::kNone, style);
+}
+
+// Test that deleting the original path invalidates the textures cached by the SW path renderer
+DEF_GPUTEST(SoftwarePathRendererCacheTest, reporter, factory) {
+    auto createPR = [](GrContext* ctx) {
+        return new GrSoftwarePathRenderer(ctx->resourceProvider(), true);
+    };
+
+    // Tessellating path renderer stores vertex buffers in the cache (for non-AA paths)
+    test_path(reporter, create_concave_path, createPR, GrAAType::kCoverage);
+
+    // Test with a style that alters the path geometry. This needs to attach the invalidation logic
+    // to the original path, not the modified path produced by the style.
+    SkPaint paint;
+    paint.setStyle(SkPaint::kStroke_Style);
+    paint.setStrokeWidth(1);
+    GrStyle style(paint);
+    test_path(reporter, create_concave_path, createPR, GrAAType::kCoverage, style);
 }
 
 #endif