gecko-dev/xpcom/ds/Tokenizer.cpp

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C++

/* -*- 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/. */
#include "Tokenizer.h"
#include "nsUnicharUtils.h"
#include <algorithm>
namespace mozilla {
static const char sWhitespaces[] = " \t";
Tokenizer::Tokenizer(const nsACString& aSource,
const char* aWhitespaces,
const char* aAdditionalWordChars)
: TokenizerBase(aWhitespaces, aAdditionalWordChars)
{
mInputFinished = true;
aSource.BeginReading(mCursor);
mRecord = mRollback = mCursor;
aSource.EndReading(mEnd);
}
Tokenizer::Tokenizer(const char* aSource,
const char* aWhitespaces,
const char* aAdditionalWordChars)
: Tokenizer(nsDependentCString(aSource), aWhitespaces, aAdditionalWordChars)
{
}
bool
Tokenizer::Next(Token& aToken)
{
if (!HasInput()) {
mHasFailed = true;
return false;
}
mRollback = mCursor;
mCursor = Parse(aToken);
AssignFragment(aToken, mRollback, mCursor);
mPastEof = aToken.Type() == TOKEN_EOF;
mHasFailed = false;
return true;
}
bool
Tokenizer::Check(const TokenType aTokenType, Token& aResult)
{
if (!HasInput()) {
mHasFailed = true;
return false;
}
nsACString::const_char_iterator next = Parse(aResult);
if (aTokenType != aResult.Type()) {
mHasFailed = true;
return false;
}
mRollback = mCursor;
mCursor = next;
AssignFragment(aResult, mRollback, mCursor);
mPastEof = aResult.Type() == TOKEN_EOF;
mHasFailed = false;
return true;
}
bool
Tokenizer::Check(const Token& aToken)
{
if (!HasInput()) {
mHasFailed = true;
return false;
}
Token parsed;
nsACString::const_char_iterator next = Parse(parsed);
if (!aToken.Equals(parsed)) {
mHasFailed = true;
return false;
}
mRollback = mCursor;
mCursor = next;
mPastEof = parsed.Type() == TOKEN_EOF;
mHasFailed = false;
return true;
}
void
Tokenizer::SkipWhites(WhiteSkipping aIncludeNewLines)
{
if (!CheckWhite() && (aIncludeNewLines == DONT_INCLUDE_NEW_LINE || !CheckEOL())) {
return;
}
nsACString::const_char_iterator rollback = mRollback;
while (CheckWhite() || (aIncludeNewLines == INCLUDE_NEW_LINE && CheckEOL())) {
}
mHasFailed = false;
mRollback = rollback;
}
void
Tokenizer::SkipUntil(Token const& aToken)
{
nsACString::const_char_iterator rollback = mCursor;
const Token eof = Token::EndOfFile();
Token t;
while (Next(t)) {
if (aToken.Equals(t) || eof.Equals(t)) {
Rollback();
break;
}
}
mRollback = rollback;
}
bool
Tokenizer::CheckChar(bool (*aClassifier)(const char aChar))
{
if (!aClassifier) {
MOZ_ASSERT(false);
return false;
}
if (!HasInput() || mCursor == mEnd) {
mHasFailed = true;
return false;
}
if (!aClassifier(*mCursor)) {
mHasFailed = true;
return false;
}
mRollback = mCursor;
++mCursor;
mHasFailed = false;
return true;
}
bool
Tokenizer::ReadChar(char* aValue)
{
MOZ_RELEASE_ASSERT(aValue);
Token t;
if (!Check(TOKEN_CHAR, t)) {
return false;
}
*aValue = t.AsChar();
return true;
}
bool
Tokenizer::ReadChar(bool (*aClassifier)(const char aChar), char* aValue)
{
MOZ_RELEASE_ASSERT(aValue);
if (!CheckChar(aClassifier)) {
return false;
}
*aValue = *mRollback;
return true;
}
bool
Tokenizer::ReadWord(nsACString& aValue)
{
Token t;
if (!Check(TOKEN_WORD, t)) {
return false;
}
aValue.Assign(t.AsString());
return true;
}
bool
Tokenizer::ReadWord(nsDependentCSubstring& aValue)
{
Token t;
if (!Check(TOKEN_WORD, t)) {
return false;
}
aValue.Rebind(t.AsString().BeginReading(), t.AsString().Length());
return true;
}
bool
Tokenizer::ReadUntil(Token const& aToken, nsACString& aResult, ClaimInclusion aInclude)
{
nsDependentCSubstring substring;
bool rv = ReadUntil(aToken, substring, aInclude);
aResult.Assign(substring);
return rv;
}
bool
Tokenizer::ReadUntil(Token const& aToken, nsDependentCSubstring& aResult, ClaimInclusion aInclude)
{
nsACString::const_char_iterator record = mRecord;
Record();
nsACString::const_char_iterator rollback = mRollback = mCursor;
bool found = false;
Token t;
while (Next(t)) {
if (aToken.Equals(t)) {
found = true;
break;
}
if (t.Equals(Token::EndOfFile())) {
// We don't want to eat it.
Rollback();
break;
}
}
Claim(aResult, aInclude);
mRollback = rollback;
mRecord = record;
return found;
}
void
Tokenizer::Rollback()
{
MOZ_ASSERT(mCursor > mRollback || mPastEof,
"Tokenizer::Rollback() cannot use twice or before any parsing");
mPastEof = false;
mHasFailed = false;
mCursor = mRollback;
}
void
Tokenizer::Record(ClaimInclusion aInclude)
{
mRecord = aInclude == INCLUDE_LAST
? mRollback
: mCursor;
}
void
Tokenizer::Claim(nsACString& aResult, ClaimInclusion aInclusion)
{
nsACString::const_char_iterator close = aInclusion == EXCLUDE_LAST
? mRollback
: mCursor;
aResult.Assign(Substring(mRecord, close));
}
void
Tokenizer::Claim(nsDependentCSubstring& aResult, ClaimInclusion aInclusion)
{
nsACString::const_char_iterator close = aInclusion == EXCLUDE_LAST
? mRollback
: mCursor;
MOZ_RELEASE_ASSERT(close >= mRecord, "Overflow!");
aResult.Rebind(mRecord, close - mRecord);
}
// TokenizerBase
TokenizerBase::TokenizerBase(const char* aWhitespaces,
const char* aAdditionalWordChars)
: mPastEof(false)
, mHasFailed(false)
, mInputFinished(true)
, mMode(Mode::FULL)
, mMinRawDelivery(1024)
, mWhitespaces(aWhitespaces ? aWhitespaces : sWhitespaces)
, mAdditionalWordChars(aAdditionalWordChars)
, mCursor(nullptr)
, mEnd(nullptr)
, mNextCustomTokenID(TOKEN_CUSTOM0)
{
}
TokenizerBase::Token
TokenizerBase::AddCustomToken(const nsACString & aValue,
ECaseSensitivity aCaseInsensitivity, bool aEnabled)
{
MOZ_ASSERT(!aValue.IsEmpty());
UniquePtr<Token>& t = *mCustomTokens.AppendElement();
t = MakeUnique<Token>();
t->mType = static_cast<TokenType>(++mNextCustomTokenID);
t->mCustomCaseInsensitivity = aCaseInsensitivity;
t->mCustomEnabled = aEnabled;
t->mCustom.Assign(aValue);
return *t;
}
void
TokenizerBase::RemoveCustomToken(Token& aToken)
{
if (aToken.mType == TOKEN_UNKNOWN) {
// Already removed
return;
}
for (UniquePtr<Token> const& custom : mCustomTokens) {
if (custom->mType == aToken.mType) {
mCustomTokens.RemoveElement(custom);
aToken.mType = TOKEN_UNKNOWN;
return;
}
}
MOZ_ASSERT(false, "Token to remove not found");
}
void
TokenizerBase::EnableCustomToken(Token const& aToken, bool aEnabled)
{
if (aToken.mType == TOKEN_UNKNOWN) {
// Already removed
return;
}
for (UniquePtr<Token> const& custom : mCustomTokens) {
if (custom->Type() == aToken.Type()) {
// This effectively destroys the token instance.
custom->mCustomEnabled = aEnabled;
return;
}
}
MOZ_ASSERT(false, "Token to change not found");
}
void
TokenizerBase::SetTokenizingMode(Mode aMode)
{
mMode = aMode;
}
bool
TokenizerBase::HasFailed() const
{
return mHasFailed;
}
bool
TokenizerBase::HasInput() const
{
return !mPastEof;
}
nsACString::const_char_iterator
TokenizerBase::Parse(Token& aToken) const
{
if (mCursor == mEnd) {
if (!mInputFinished) {
return mCursor;
}
aToken = Token::EndOfFile();
return mEnd;
}
MOZ_RELEASE_ASSERT(mEnd >= mCursor, "Overflow!");
nsACString::size_type available = mEnd - mCursor;
uint32_t longestCustom = 0;
for (UniquePtr<Token> const& custom : mCustomTokens) {
if (IsCustom(mCursor, *custom, &longestCustom)) {
aToken = *custom;
return mCursor + custom->mCustom.Length();
}
}
if (!mInputFinished && available < longestCustom) {
// Not enough data to deterministically decide.
return mCursor;
}
nsACString::const_char_iterator next = mCursor;
if (mMode == Mode::CUSTOM_ONLY) {
// We have to do a brute-force search for all of the enabled custom
// tokens.
while (next < mEnd) {
++next;
for (UniquePtr<Token> const& custom : mCustomTokens) {
if (IsCustom(next, *custom)) {
aToken = Token::Raw();
return next;
}
}
}
if (mInputFinished) {
// End of the data reached.
aToken = Token::Raw();
return next;
}
if (longestCustom < available && available > mMinRawDelivery) {
// We can return some data w/o waiting for either a custom token
// or call to FinishData() when we leave the tail where all the
// custom tokens potentially fit, so we can't lose only partially
// delivered tokens. This preserves reasonable granularity.
aToken = Token::Raw();
return mEnd - longestCustom + 1;
}
// Not enough data to deterministically decide.
return mCursor;
}
enum State {
PARSE_INTEGER,
PARSE_WORD,
PARSE_CRLF,
PARSE_LF,
PARSE_WS,
PARSE_CHAR,
} state;
if (IsWordFirst(*next)) {
state = PARSE_WORD;
} else if (IsNumber(*next)) {
state = PARSE_INTEGER;
} else if (strchr(mWhitespaces, *next)) { // not UTF-8 friendly?
state = PARSE_WS;
} else if (*next == '\r') {
state = PARSE_CRLF;
} else if (*next == '\n') {
state = PARSE_LF;
} else {
state = PARSE_CHAR;
}
mozilla::CheckedUint64 resultingNumber = 0;
while (next < mEnd) {
switch (state) {
case PARSE_INTEGER:
// Keep it simple for now
resultingNumber *= 10;
resultingNumber += static_cast<uint64_t>(*next - '0');
++next;
if (IsPending(next)) {
break;
}
if (IsEnd(next) || !IsNumber(*next)) {
if (!resultingNumber.isValid()) {
aToken = Token::Error();
} else {
aToken = Token::Number(resultingNumber.value());
}
return next;
}
break;
case PARSE_WORD:
++next;
if (IsPending(next)) {
break;
}
if (IsEnd(next) || !IsWord(*next)) {
aToken = Token::Word(Substring(mCursor, next));
return next;
}
break;
case PARSE_CRLF:
++next;
if (IsPending(next)) {
break;
}
if (!IsEnd(next) && *next == '\n') { // LF is optional
++next;
}
aToken = Token::NewLine();
return next;
case PARSE_LF:
++next;
aToken = Token::NewLine();
return next;
case PARSE_WS:
++next;
aToken = Token::Whitespace();
return next;
case PARSE_CHAR:
++next;
aToken = Token::Char(*mCursor);
return next;
} // switch (state)
} // while (next < end)
MOZ_ASSERT(!mInputFinished);
return mCursor;
}
bool
TokenizerBase::IsEnd(const nsACString::const_char_iterator& caret) const
{
return caret == mEnd;
}
bool
TokenizerBase::IsPending(const nsACString::const_char_iterator& caret) const
{
return IsEnd(caret) && !mInputFinished;
}
bool
TokenizerBase::IsWordFirst(const char aInput) const
{
// TODO: make this fully work with unicode
return (ToLowerCase(static_cast<uint32_t>(aInput)) !=
ToUpperCase(static_cast<uint32_t>(aInput))) ||
'_' == aInput ||
(mAdditionalWordChars ? !!strchr(mAdditionalWordChars, aInput) : false);
}
bool
TokenizerBase::IsWord(const char aInput) const
{
return IsWordFirst(aInput) || IsNumber(aInput);
}
bool
TokenizerBase::IsNumber(const char aInput) const
{
// TODO: are there unicode numbers?
return aInput >= '0' && aInput <= '9';
}
bool
TokenizerBase::IsCustom(const nsACString::const_char_iterator & caret,
const Token & aCustomToken,
uint32_t * aLongest) const
{
MOZ_ASSERT(aCustomToken.mType > TOKEN_CUSTOM0);
if (!aCustomToken.mCustomEnabled) {
return false;
}
if (aLongest) {
*aLongest = std::max(*aLongest, aCustomToken.mCustom.Length());
}
// This is not very likely to happen according to how we call this method
// and since it's on a hot path, it's just a diagnostic assert,
// not a release assert.
MOZ_DIAGNOSTIC_ASSERT(mEnd >= caret, "Overflow?");
uint32_t inputLength = mEnd - caret;
if (aCustomToken.mCustom.Length() > inputLength) {
return false;
}
nsDependentCSubstring inputFragment(caret, aCustomToken.mCustom.Length());
if (aCustomToken.mCustomCaseInsensitivity == CASE_INSENSITIVE) {
return inputFragment.Equals(aCustomToken.mCustom, nsCaseInsensitiveUTF8StringComparator());
}
return inputFragment.Equals(aCustomToken.mCustom);
}
void TokenizerBase::AssignFragment(Token& aToken,
nsACString::const_char_iterator begin,
nsACString::const_char_iterator end)
{
aToken.AssignFragment(begin, end);
}
// TokenizerBase::Token
TokenizerBase::Token::Token()
: mType(TOKEN_UNKNOWN)
, mChar(0)
, mInteger(0)
, mCustomCaseInsensitivity(CASE_SENSITIVE)
, mCustomEnabled(false)
{
}
TokenizerBase::Token::Token(const Token& aOther)
: mType(aOther.mType)
, mCustom(aOther.mCustom)
, mChar(aOther.mChar)
, mInteger(aOther.mInteger)
, mCustomCaseInsensitivity(aOther.mCustomCaseInsensitivity)
, mCustomEnabled(aOther.mCustomEnabled)
{
if (mType == TOKEN_WORD || mType > TOKEN_CUSTOM0) {
mWord.Rebind(aOther.mWord.BeginReading(), aOther.mWord.Length());
}
}
TokenizerBase::Token&
TokenizerBase::Token::operator=(const Token& aOther)
{
mType = aOther.mType;
mCustom = aOther.mCustom;
mChar = aOther.mChar;
mWord.Rebind(aOther.mWord.BeginReading(), aOther.mWord.Length());
mInteger = aOther.mInteger;
mCustomCaseInsensitivity = aOther.mCustomCaseInsensitivity;
mCustomEnabled = aOther.mCustomEnabled;
return *this;
}
void
TokenizerBase::Token::AssignFragment(nsACString::const_char_iterator begin,
nsACString::const_char_iterator end)
{
MOZ_RELEASE_ASSERT(end >= begin, "Overflow!");
mFragment.Rebind(begin, end - begin);
}
// static
TokenizerBase::Token
TokenizerBase::Token::Raw()
{
Token t;
t.mType = TOKEN_RAW;
return t;
}
// static
TokenizerBase::Token
TokenizerBase::Token::Word(const nsACString& aValue)
{
Token t;
t.mType = TOKEN_WORD;
t.mWord.Rebind(aValue.BeginReading(), aValue.Length());
return t;
}
// static
TokenizerBase::Token
TokenizerBase::Token::Char(const char aValue)
{
Token t;
t.mType = TOKEN_CHAR;
t.mChar = aValue;
return t;
}
// static
TokenizerBase::Token
TokenizerBase::Token::Number(const uint64_t aValue)
{
Token t;
t.mType = TOKEN_INTEGER;
t.mInteger = aValue;
return t;
}
// static
TokenizerBase::Token
TokenizerBase::Token::Whitespace()
{
Token t;
t.mType = TOKEN_WS;
t.mChar = '\0';
return t;
}
// static
TokenizerBase::Token
TokenizerBase::Token::NewLine()
{
Token t;
t.mType = TOKEN_EOL;
return t;
}
// static
TokenizerBase::Token
TokenizerBase::Token::EndOfFile()
{
Token t;
t.mType = TOKEN_EOF;
return t;
}
// static
TokenizerBase::Token
TokenizerBase::Token::Error()
{
Token t;
t.mType = TOKEN_ERROR;
return t;
}
bool
TokenizerBase::Token::Equals(const Token& aOther) const
{
if (mType != aOther.mType) {
return false;
}
switch (mType) {
case TOKEN_INTEGER:
return AsInteger() == aOther.AsInteger();
case TOKEN_WORD:
return AsString() == aOther.AsString();
case TOKEN_CHAR:
return AsChar() == aOther.AsChar();
default:
return true;
}
}
char
TokenizerBase::Token::AsChar() const
{
MOZ_ASSERT(mType == TOKEN_CHAR || mType == TOKEN_WS);
return mChar;
}
nsDependentCSubstring
TokenizerBase::Token::AsString() const
{
MOZ_ASSERT(mType == TOKEN_WORD);
return mWord;
}
uint64_t
TokenizerBase::Token::AsInteger() const
{
MOZ_ASSERT(mType == TOKEN_INTEGER);
return mInteger;
}
} // mozilla