Revamp style resolver stats

Source/core/css/resolver/StyleResolverStats.cpp

Index: Source/core/css/resolver/StyleResolverStats.cpp
diff --git a/Source/core/css/resolver/StyleResolverStats.cpp b/Source/core/css/resolver/StyleResolverStats.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..bb795bfa34c2ae2fdca34e2cbf171b1d1d832fba
--- /dev/null
+++ b/Source/core/css/resolver/StyleResolverStats.cpp
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2013 Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "core/css/resolver/StyleResolverStats.h"
+
+#include "wtf/text/CString.h"
+#include "wtf/text/StringBuilder.h"
+
+#define PERCENT(x, y) ((!y) ? 0 : (((x) * 100.0) / (y)))
+
+namespace WebCore {
+
+void StyleResolverStats::reset()
+{
+    sharedStyleLookups = 0;
+    sharedStyleCandidates = 0;
+    sharedStyleFound = 0;
+    sharedStyleMissed = 0;
+    sharedStyleRejectedByUncommonAttributeRules = 0;
+    sharedStyleRejectedBySiblingRules = 0;
+    sharedStyleRejectedByParent = 0;
+    matchedPropertyApply = 0;
+    matchedPropertyCacheHit = 0;
+    matchedPropertyCacheInheritedHit = 0;
+    matchedPropertyCacheAdded = 0;
+}
+
+String StyleResolverStats::report() const
+{
+    StringBuilder output;
+
+    unsigned sharedStylesRejected = sharedStyleRejectedByUncommonAttributeRules + sharedStyleRejectedBySiblingRules + sharedStyleRejectedByParent;
+    unsigned sharedStylesUsed = sharedStyleFound - sharedStylesRejected;
+
+    output.append("Style sharing:\n");
+    output.append(String::format("  %u elements were added to the sharing candidate list.\n", sharedStyleCandidates));
+    output.append(String::format("  %u calls were made to findSharedStyle, %u found a candidate to share with (%.2f%%).\n", sharedStyleLookups, sharedStyleFound, PERCENT(sharedStyleFound, sharedStyleLookups)));
+    if (printMissedCandidateCount)
+        output.append(String::format("  %u candidates could have matched but were not in the list when searching (%.2f%%).\n", sharedStyleMissed, PERCENT(sharedStyleMissed, sharedStyleLookups)));
+    output.append(String::format("  %u of found styles were rejected (%.2f%%), %.2f%% by uncommon attribute rules, %.2f%% by sibling rules and %.2f%% by parents disabling sharing.\n",
+        sharedStylesRejected,
+        PERCENT(sharedStylesRejected, sharedStyleFound),
+        PERCENT(sharedStyleRejectedByUncommonAttributeRules, sharedStylesRejected),
+        PERCENT(sharedStyleRejectedBySiblingRules, sharedStylesRejected),
+        PERCENT(sharedStyleRejectedByParent, sharedStylesRejected)));
+    output.append(String::format("  %u of found styles were used for sharing (%.2f%%).\n", sharedStylesUsed, PERCENT(sharedStylesUsed, sharedStyleFound)));
+    output.append(String::format("  %.2f%% of calls to findSharedStyle returned a shared style.\n", PERCENT(sharedStylesUsed, sharedStyleLookups)));
+
+    output.append("\n");
+
+    output.append("Matched property cache:\n");
+    output.append(String::format("  %u calls to applyMatchedProperties, %u hit the cache (%.2f%%).\n", matchedPropertyApply, matchedPropertyCacheHit, PERCENT(matchedPropertyCacheHit, matchedPropertyApply)));
+    output.append(String::format("  %u cache hits also shared the inherited style (%.2f%%).\n", matchedPropertyCacheInheritedHit, PERCENT(matchedPropertyCacheInheritedHit, matchedPropertyCacheHit)));
+    output.append(String::format("  %u styles created in applyMatchedProperties were added to the cache (%.2f%%).\n", matchedPropertyCacheAdded, PERCENT(matchedPropertyCacheAdded, matchedPropertyApply)));
+
+    return output.toString();
+}
+
+} // namespace WebCore