1 files changed, 99 insertions, 0 deletions
diff --git a/layout/xul/tree/nsTreeStyleCache.cpp b/layout/xul/tree/nsTreeStyleCache.cpp
new file mode 100644
index 0000000000..74b8a89c47
--- /dev/null
+++ b/layout/xul/tree/nsTreeStyleCache.cpp
@@ -0,0 +1,99 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsTreeStyleCache.h"
+#include "nsStyleSet.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/StyleSetHandle.h"
+#include "mozilla/StyleSetHandleInlines.h"
+
+nsTreeStyleCache::Transition::Transition(DFAState aState, nsIAtom* aSymbol)
+  : mState(aState), mInputSymbol(aSymbol)
+{
+}
+
+bool
+nsTreeStyleCache::Transition::operator==(const Transition& aOther) const
+{
+  return aOther.mState == mState && aOther.mInputSymbol == mInputSymbol;
+}
+
+uint32_t
+nsTreeStyleCache::Transition::Hash() const
+{
+  // Make a 32-bit integer that combines the low-order 16 bits of the state and the input symbol.
+  uint32_t hb = mState << 16;
+  uint32_t lb = (NS_PTR_TO_UINT32(mInputSymbol.get()) << 16) >> 16;
+  return hb+lb;
+}
+
+
+// The style context cache impl
+nsStyleContext*
+nsTreeStyleCache::GetStyleContext(nsICSSPseudoComparator* aComparator,
+                                  nsPresContext* aPresContext,
+                                  nsIContent* aContent,
+                                  nsStyleContext* aContext,
+                                  nsIAtom* aPseudoElement,
+                                  const AtomArray & aInputWord)
+{
+  uint32_t count = aInputWord.Length();
+
+  // Go ahead and init the transition table.
+  if (!mTransitionTable) {
+    // Automatic miss. Build the table
+    mTransitionTable = new TransitionTable();
+  }
+
+  // The first transition is always made off the supplied pseudo-element.
+  Transition transition(0, aPseudoElement);
+  DFAState currState = mTransitionTable->Get(transition);
+
+  if (!currState) {
+    // We had a miss. Make a new state and add it to our hash.
+    currState = mNextState;
+    mNextState++;
+    mTransitionTable->Put(transition, currState);
+  }
+
+  for (uint32_t i = 0; i < count; i++) {
+    Transition transition(currState, aInputWord[i]);
+    currState = mTransitionTable->Get(transition);
+
+    if (!currState) {
+      // We had a miss. Make a new state and add it to our hash.
+      currState = mNextState;
+      mNextState++;
+      mTransitionTable->Put(transition, currState);
+    }
+  }
+
+  // We're in a final state.
+  // Look up our style context for this state.
+  nsStyleContext* result = nullptr;
+  if (mCache) {
+    result = mCache->GetWeak(currState);
+  }
+  if (!result) {
+    // We missed the cache. Resolve this pseudo-style.
+    // XXXheycam ServoStyleSets do not support XUL tree styles.
+    if (aPresContext->StyleSet()->IsServo()) {
+      MOZ_CRASH("stylo: ServoStyleSets should not support XUL tree styles yet");
+    }
+    RefPtr<nsStyleContext> newResult = aPresContext->StyleSet()->AsGecko()->
+      ResolveXULTreePseudoStyle(aContent->AsElement(), aPseudoElement,
+                                aContext, aComparator);
+
+    // Put the style context in our table, transferring the owning reference to the table.
+    if (!mCache) {
+      mCache = new StyleContextCache();
+    }
+    result = newResult.get();
+    mCache->Put(currState, newResult.forget());
+  }
+
+  return result;
+}
+