1 files changed, 307 insertions, 0 deletions
diff --git a/js/src/vm/RegExpStatics.h b/js/src/vm/RegExpStatics.h
new file mode 100644
index 0000000000..d4918014ea
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+++ b/js/src/vm/RegExpStatics.h
@@ -0,0 +1,307 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * 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/. */
+
+#ifndef vm_RegExpStatics_h
+#define vm_RegExpStatics_h
+
+#include "gc/Marking.h"
+#include "vm/JSContext.h"
+#include "vm/MatchPairs.h"
+#include "vm/RegExpShared.h"
+#include "vm/Runtime.h"
+
+namespace js {
+
+class GlobalObject;
+class RegExpStaticsObject;
+
+class RegExpStatics {
+  /* The latest RegExp output, set after execution. */
+  VectorMatchPairs matches;
+  HeapPtr<JSLinearString*> matchesInput;
+
+  /*
+   * The previous RegExp input, used to resolve lazy state.
+   * A raw RegExpShared cannot be stored because it may be in
+   * a different compartment via evalcx().
+   */
+  HeapPtr<JSAtom*> lazySource;
+  JS::RegExpFlags lazyFlags;
+  size_t lazyIndex;
+
+  /* The latest RegExp input, set before execution. */
+  HeapPtr<JSString*> pendingInput;
+
+  /*
+   * If non-zero, |matchesInput| and the |lazy*| fields may be used
+   * to replay the last executed RegExp, and |matches| is invalid.
+   */
+  int32_t pendingLazyEvaluation;
+
+ public:
+  RegExpStatics() { clear(); }
+  static RegExpStaticsObject* create(JSContext* cx);
+
+ private:
+  bool executeLazy(JSContext* cx);
+
+  inline void checkInvariants();
+
+  /*
+   * Check whether a match for pair |pairNum| occurred.  If so, allocate and
+   * store the match string in |*out|; otherwise place |undefined| in |*out|.
+   */
+  bool makeMatch(JSContext* cx, size_t pairNum, MutableHandleValue out);
+  bool createDependent(JSContext* cx, size_t start, size_t end,
+                       MutableHandleValue out);
+
+ public:
+  /* Mutators. */
+  inline bool updateFromMatchPairs(JSContext* cx, JSLinearString* input,
+                                   VectorMatchPairs& newPairs);
+
+  inline void clear();
+
+  /* Corresponds to JSAPI functionality to set the pending RegExp input. */
+  void reset(JSString* newInput) {
+    clear();
+    pendingInput = newInput;
+    checkInvariants();
+  }
+
+  inline void setPendingInput(JSString* newInput);
+
+ public:
+  void trace(JSTracer* trc) {
+    /*
+     * Changes to this function must also be reflected in
+     * RegExpStatics::AutoRooter::trace().
+     */
+    TraceNullableEdge(trc, &matchesInput, "res->matchesInput");
+    TraceNullableEdge(trc, &lazySource, "res->lazySource");
+    TraceNullableEdge(trc, &pendingInput, "res->pendingInput");
+  }
+
+  /* Value creators. */
+
+  bool createPendingInput(JSContext* cx, MutableHandleValue out);
+  bool createLastMatch(JSContext* cx, MutableHandleValue out);
+  bool createLastParen(JSContext* cx, MutableHandleValue out);
+  bool createParen(JSContext* cx, size_t pairNum, MutableHandleValue out);
+  bool createLeftContext(JSContext* cx, MutableHandleValue out);
+  bool createRightContext(JSContext* cx, MutableHandleValue out);
+
+  static size_t offsetOfPendingInput() {
+    return offsetof(RegExpStatics, pendingInput);
+  }
+
+  static size_t offsetOfMatchesInput() {
+    return offsetof(RegExpStatics, matchesInput);
+  }
+
+  static size_t offsetOfLazySource() {
+    return offsetof(RegExpStatics, lazySource);
+  }
+
+  static size_t offsetOfLazyFlags() {
+    return offsetof(RegExpStatics, lazyFlags);
+  }
+
+  static size_t offsetOfLazyIndex() {
+    return offsetof(RegExpStatics, lazyIndex);
+  }
+
+  static size_t offsetOfPendingLazyEvaluation() {
+    return offsetof(RegExpStatics, pendingLazyEvaluation);
+  }
+};
+
+inline bool RegExpStatics::createDependent(JSContext* cx, size_t start,
+                                           size_t end, MutableHandleValue out) {
+  /* Private function: caller must perform lazy evaluation. */
+  MOZ_ASSERT(!pendingLazyEvaluation);
+
+  MOZ_ASSERT(start <= end);
+  MOZ_ASSERT(end <= matchesInput->length());
+  JSString* str = NewDependentString(cx, matchesInput, start, end - start);
+  if (!str) {
+    return false;
+  }
+  out.setString(str);
+  return true;
+}
+
+inline bool RegExpStatics::createPendingInput(JSContext* cx,
+                                              MutableHandleValue out) {
+  /* Lazy evaluation need not be resolved to return the input. */
+  out.setString(pendingInput ? pendingInput.get()
+                             : cx->runtime()->emptyString.ref());
+  return true;
+}
+
+inline bool RegExpStatics::makeMatch(JSContext* cx, size_t pairNum,
+                                     MutableHandleValue out) {
+  /* Private function: caller must perform lazy evaluation. */
+  MOZ_ASSERT(!pendingLazyEvaluation);
+
+  if (matches.empty() || pairNum >= matches.pairCount() ||
+      matches[pairNum].isUndefined()) {
+    out.setUndefined();
+    return true;
+  }
+
+  const MatchPair& pair = matches[pairNum];
+  return createDependent(cx, pair.start, pair.limit, out);
+}
+
+inline bool RegExpStatics::createLastMatch(JSContext* cx,
+                                           MutableHandleValue out) {
+  if (!executeLazy(cx)) {
+    return false;
+  }
+  return makeMatch(cx, 0, out);
+}
+
+inline bool RegExpStatics::createLastParen(JSContext* cx,
+                                           MutableHandleValue out) {
+  if (!executeLazy(cx)) {
+    return false;
+  }
+
+  if (matches.empty() || matches.pairCount() == 1) {
+    out.setString(cx->runtime()->emptyString);
+    return true;
+  }
+  const MatchPair& pair = matches[matches.pairCount() - 1];
+  if (pair.start == -1) {
+    out.setString(cx->runtime()->emptyString);
+    return true;
+  }
+  MOZ_ASSERT(pair.start >= 0 && pair.limit >= 0);
+  MOZ_ASSERT(pair.limit >= pair.start);
+  return createDependent(cx, pair.start, pair.limit, out);
+}
+
+inline bool RegExpStatics::createParen(JSContext* cx, size_t pairNum,
+                                       MutableHandleValue out) {
+  MOZ_ASSERT(pairNum >= 1);
+  if (!executeLazy(cx)) {
+    return false;
+  }
+
+  if (matches.empty() || pairNum >= matches.pairCount()) {
+    out.setString(cx->runtime()->emptyString);
+    return true;
+  }
+  return makeMatch(cx, pairNum, out);
+}
+
+inline bool RegExpStatics::createLeftContext(JSContext* cx,
+                                             MutableHandleValue out) {
+  if (!executeLazy(cx)) {
+    return false;
+  }
+
+  if (matches.empty()) {
+    out.setString(cx->runtime()->emptyString);
+    return true;
+  }
+  if (matches[0].start < 0) {
+    out.setUndefined();
+    return true;
+  }
+  return createDependent(cx, 0, matches[0].start, out);
+}
+
+inline bool RegExpStatics::createRightContext(JSContext* cx,
+                                              MutableHandleValue out) {
+  if (!executeLazy(cx)) {
+    return false;
+  }
+
+  if (matches.empty()) {
+    out.setString(cx->runtime()->emptyString);
+    return true;
+  }
+  if (matches[0].limit < 0) {
+    out.setUndefined();
+    return true;
+  }
+  return createDependent(cx, matches[0].limit, matchesInput->length(), out);
+}
+
+inline bool RegExpStatics::updateFromMatchPairs(JSContext* cx,
+                                                JSLinearString* input,
+                                                VectorMatchPairs& newPairs) {
+  MOZ_ASSERT(input);
+
+  /* Unset all lazy state. */
+  pendingLazyEvaluation = false;
+  this->lazySource = nullptr;
+  this->lazyIndex = size_t(-1);
+
+  BarrieredSetPair<JSString, JSLinearString>(cx->zone(), pendingInput, input,
+                                             matchesInput, input);
+
+  if (!matches.initArrayFrom(newPairs)) {
+    ReportOutOfMemory(cx);
+    return false;
+  }
+
+  return true;
+}
+
+inline void RegExpStatics::clear() {
+  matches.forgetArray();
+  matchesInput = nullptr;
+  lazySource = nullptr;
+  lazyFlags = JS::RegExpFlag::NoFlags;
+  lazyIndex = size_t(-1);
+  pendingInput = nullptr;
+  pendingLazyEvaluation = false;
+}
+
+inline void RegExpStatics::setPendingInput(JSString* newInput) {
+  pendingInput = newInput;
+}
+
+inline void RegExpStatics::checkInvariants() {
+#ifdef DEBUG
+  if (pendingLazyEvaluation) {
+    MOZ_ASSERT(lazySource);
+    MOZ_ASSERT(matchesInput);
+    MOZ_ASSERT(lazyIndex != size_t(-1));
+    return;
+  }
+
+  if (matches.empty()) {
+    MOZ_ASSERT(!matchesInput);
+    return;
+  }
+
+  /* Pair count is non-zero, so there must be match pairs input. */
+  MOZ_ASSERT(matchesInput);
+  size_t mpiLen = matchesInput->length();
+
+  /* Both members of the first pair must be non-negative. */
+  MOZ_ASSERT(!matches[0].isUndefined());
+  MOZ_ASSERT(matches[0].limit >= 0);
+
+  /* Present pairs must be valid. */
+  for (size_t i = 0; i < matches.pairCount(); i++) {
+    if (matches[i].isUndefined()) {
+      continue;
+    }
+    const MatchPair& pair = matches[i];
+    MOZ_ASSERT(mpiLen >= size_t(pair.limit) && pair.limit >= pair.start &&
+               pair.start >= 0);
+  }
+#endif /* DEBUG */
+}
+
+} /* namespace js */
+
+#endif /* vm_RegExpStatics_h */