1 files changed, 65 insertions, 0 deletions
diff --git a/dom/xslt/xslt/txPatternOptimizer.cpp b/dom/xslt/xslt/txPatternOptimizer.cpp
new file mode 100644
index 0000000000..4d0a68d188
--- /dev/null
+++ b/dom/xslt/xslt/txPatternOptimizer.cpp
@@ -0,0 +1,65 @@
+/* -*- Mode: C++; tab-width: 4; 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 "txPatternOptimizer.h"
+#include "txXSLTPatterns.h"
+
+void txPatternOptimizer::optimize(txPattern* aInPattern,
+                                  txPattern** aOutPattern) {
+  *aOutPattern = nullptr;
+
+  // First optimize sub expressions
+  uint32_t i = 0;
+  Expr* subExpr;
+  while ((subExpr = aInPattern->getSubExprAt(i))) {
+    Expr* newExpr = nullptr;
+    mXPathOptimizer.optimize(subExpr, &newExpr);
+    if (newExpr) {
+      delete subExpr;
+      aInPattern->setSubExprAt(i, newExpr);
+    }
+
+    ++i;
+  }
+
+  // Then optimize sub patterns
+  txPattern* subPattern;
+  i = 0;
+  while ((subPattern = aInPattern->getSubPatternAt(i))) {
+    txPattern* newPattern = nullptr;
+    optimize(subPattern, &newPattern);
+    if (newPattern) {
+      delete subPattern;
+      aInPattern->setSubPatternAt(i, newPattern);
+    }
+
+    ++i;
+  }
+
+  // Finally see if current pattern can be optimized
+  switch (aInPattern->getType()) {
+    case txPattern::STEP_PATTERN:
+      optimizeStep(aInPattern, aOutPattern);
+      return;
+
+    default:
+      break;
+  }
+}
+
+void txPatternOptimizer::optimizeStep(txPattern* aInPattern,
+                                      txPattern** aOutPattern) {
+  txStepPattern* step = static_cast<txStepPattern*>(aInPattern);
+
+  // Test for predicates that can be combined into the nodetest
+  Expr* pred;
+  while ((pred = step->getSubExprAt(0)) &&
+         !pred->canReturnType(Expr::NUMBER_RESULT) &&
+         !pred->isSensitiveTo(Expr::NODESET_CONTEXT)) {
+    txNodeTest* predTest = new txPredicatedNodeTest(step->getNodeTest(), pred);
+    step->dropFirst();
+    step->setNodeTest(predTest);
+  }
+}