Caching the result of readPixelsSupported

The call was calling GR_GL_GetIntegerv 2 times for each readPixels
and thus was causing a loss of performance

(resubmit of issue 344793008)

Benchmark url: http://packages.gkny.fr/tst/index.html

BUG=skia:2681

Committed: https://skia.googlesource.com/skia/+/753a2964afe5661ce9b2a8ca77ca9d0aabd3173c

Committed: https://skia.googlesource.com/skia/+/8339371f1ec3c57a0741932fd96bff32c53d4e54

Review URL: https://codereview.chromium.org/364193004

1 files changed, 91 insertions, 0 deletions

diff --git a/tests/THashCache.cpp b/tests/THashCache.cpp
new file mode 100644
index 0000000000..7797431553
--- /dev/null
+++ b/tests/THashCache.cpp
@@ -0,0 +1,91 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "Test.h"
+#include "SkTHashCache.h"
+
+
+// Tests the SkTHashCache<T> class template.
+
+struct Tint {
+    uint32_t value;
+
+    bool operator==(const Tint& rhs) const {
+        return value == rhs.value;
+    }
+};
+
+class Element {
+public:
+
+    bool operator==(const Element& rhs) const {
+        return value == rhs.value && key == rhs.key;
+    }
+
+    static const Tint& GetKey(const Element& element) {
+        return element.key;
+    }
+
+    static uint32_t Hash(const Tint& key) {
+        return key.value;
+    }
+
+    Element(Tint key, int value) : key(key), value(value) {
+    }
+
+    Tint key;
+    int value;
+};
+
+typedef SkTHashCache<Element, Tint> CacheType;
+
+DEF_TEST(THashCache, reporter) {
+    Tint k11 = {11};
+    Element e11(k11, 22);
+
+    e11.value = e11.value;
+    Element e11Collision(k11, 0);
+    //    Element e42(4, 2);
+
+    //Some tests for the class Element
+    REPORTER_ASSERT(reporter, Element::GetKey(e11) == k11);
+    REPORTER_ASSERT(reporter, Element::Hash(k11) == 11);
+
+    CacheType cache;
+
+    // Is the cahce correctly initialized ?
+    REPORTER_ASSERT(reporter, 0 == cache.size());
+    REPORTER_ASSERT(reporter, NULL == cache.find(k11));
+
+    Element& e11_c = cache.add(e11);
+    e11_c.value = e11_c.value;
+
+    // Tests for simple insertion, verifying that the returned element
+    // has the same values as the original one
+    REPORTER_ASSERT(reporter, 1 == cache.size());
+    REPORTER_ASSERT(reporter, NULL != cache.find(k11));
+    REPORTER_ASSERT(reporter, e11_c == e11);
+
+    Element& e11Collision_c = cache.add(e11Collision);
+    // Verifying that, in case of collision, the element alerady in the cache is not removed
+    REPORTER_ASSERT(reporter, e11Collision_c == e11);
+    REPORTER_ASSERT(reporter, 1 == cache.size());
+
+    Tint k42 = {42};
+    Element e42(k42, 2);
+    cache.add(e42);
+    // Can we add more than one element?
+    REPORTER_ASSERT(reporter, NULL != cache.find(k11));
+    REPORTER_ASSERT(reporter, NULL != cache.find(k42));
+    REPORTER_ASSERT(reporter, 2 == cache.size());
+
+    cache.reset();
+    // Does clear do its job?
+    REPORTER_ASSERT(reporter, 0 == cache.size());
+    REPORTER_ASSERT(reporter, NULL == cache.find(k11));
+    REPORTER_ASSERT(reporter, NULL == cache.find(k42));
+}