RegExpStatics.h
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* 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/MatchPairs.h"
#include "vm/RegExpObject.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;
RegExpFlag 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(ExclusiveContext* cx, Handle<GlobalObject*> parent);
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);
struct InitBuffer {};
explicit RegExpStatics(InitBuffer) {}
public:
/* Mutators. */
inline void updateLazily(JSContext* cx, JSLinearString* input,
RegExpShared* shared, size_t lastIndex);
inline bool updateFromMatchPairs(JSContext* cx, JSLinearString* input, MatchPairs& newPairs);
inline void clear();
/* Corresponds to JSAPI functionality to set the pending RegExp input. */
void reset(JSContext* cx, JSString* newInput) {
clear();
pendingInput = newInput;
checkInvariants();
}
inline void setPendingInput(JSString* newInput);
public:
/* Default match accessor. */
const MatchPairs& getMatches() const {
/* Safe: only used by String methods, which do not set lazy mode. */
MOZ_ASSERT(!pendingLazyEvaluation);
return matches;
}
JSString* getPendingInput() const { return pendingInput; }
void mark(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);
/* Infallible substring creators. */
void getParen(size_t pairNum, JSSubString* out) const;
void getLastMatch(JSSubString* out) const;
void getLastParen(JSSubString* out) const;
void getLeftContext(JSSubString* out) const;
void getRightContext(JSSubString* out) const;
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);
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 void
RegExpStatics::getParen(size_t pairNum, JSSubString* out) const
{
MOZ_ASSERT(!pendingLazyEvaluation);
MOZ_ASSERT(pairNum >= 1 && pairNum < matches.pairCount());
const MatchPair& pair = matches[pairNum];
if (pair.isUndefined()) {
out->initEmpty(matchesInput);
return;
}
out->init(matchesInput, pair.start, pair.length());
}
inline void
RegExpStatics::getLastMatch(JSSubString* out) const
{
MOZ_ASSERT(!pendingLazyEvaluation);
if (matches.empty()) {
out->initEmpty(matchesInput);
return;
}
MOZ_ASSERT(matchesInput);
MOZ_ASSERT(matches[0].limit >= matches[0].start);
out->init(matchesInput, matches[0].start, matches[0].length());
}
inline void
RegExpStatics::getLastParen(JSSubString* out) const
{
MOZ_ASSERT(!pendingLazyEvaluation);
/* Note: the first pair is the whole match. */
if (matches.empty() || matches.pairCount() == 1) {
out->initEmpty(matchesInput);
return;
}
getParen(matches.parenCount(), out);
}
inline void
RegExpStatics::getLeftContext(JSSubString* out) const
{
MOZ_ASSERT(!pendingLazyEvaluation);
if (matches.empty()) {
out->initEmpty(matchesInput);
return;
}
out->init(matchesInput, 0, matches[0].start);
}
inline void
RegExpStatics::getRightContext(JSSubString* out) const
{
MOZ_ASSERT(!pendingLazyEvaluation);
if (matches.empty()) {
out->initEmpty(matchesInput);
return;
}
MOZ_ASSERT(matches[0].limit <= int(matchesInput->length()));
size_t length = matchesInput->length() - matches[0].limit;
out->init(matchesInput, matches[0].limit, length);
}
inline void
RegExpStatics::updateLazily(JSContext* cx, JSLinearString* input,
RegExpShared* shared, size_t lastIndex)
{
MOZ_ASSERT(input && shared);
BarrieredSetPair<JSString, JSLinearString>(cx->zone(),
pendingInput, input,
matchesInput, input);
lazySource = shared->source;
lazyFlags = shared->flags;
lazyIndex = lastIndex;
pendingLazyEvaluation = 1;
}
inline bool
RegExpStatics::updateFromMatchPairs(JSContext* cx, JSLinearString* input, MatchPairs& 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 = RegExpFlag(0);
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 */
