summaryrefslogtreecommitdiffstats
path: root/src/lib/dns/master_lexer.cc
diff options
context:
space:
mode:
Diffstat (limited to 'src/lib/dns/master_lexer.cc')
-rw-r--r--src/lib/dns/master_lexer.cc614
1 files changed, 614 insertions, 0 deletions
diff --git a/src/lib/dns/master_lexer.cc b/src/lib/dns/master_lexer.cc
new file mode 100644
index 0000000..0d1292e
--- /dev/null
+++ b/src/lib/dns/master_lexer.cc
@@ -0,0 +1,614 @@
+// Copyright (C) 2012-2015,2021 Internet Systems Consortium, Inc. ("ISC")
+//
+// 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 <config.h>
+
+#include <exceptions/exceptions.h>
+
+#include <dns/master_lexer.h>
+#include <dns/master_lexer_inputsource.h>
+#include <dns/master_lexer_state.h>
+
+#include <boost/foreach.hpp>
+#include <boost/shared_ptr.hpp>
+#include <boost/lexical_cast.hpp>
+
+#include <bitset>
+#include <cassert>
+#include <limits>
+#include <string>
+#include <vector>
+
+namespace isc {
+namespace dns {
+
+// The definition of SOURCE_SIZE_UNKNOWN. Note that we initialize it using
+// a method of another library. Technically, this could trigger a static
+// initialization fiasco. But in this particular usage it's very unlikely
+// to happen because this value is expected to be used only as a return
+// value of a MasterLexer's method, and its constructor needs definitions
+// here.
+const size_t MasterLexer::SOURCE_SIZE_UNKNOWN =
+ std::numeric_limits<size_t>::max();
+
+namespace {
+typedef boost::shared_ptr<master_lexer_internal::InputSource> InputSourcePtr;
+} // end unnamed namespace
+using namespace master_lexer_internal;
+
+
+struct MasterLexer::MasterLexerImpl {
+ MasterLexerImpl() : source_(NULL), token_(MasterToken::NOT_STARTED),
+ total_size_(0), popped_size_(0),
+ paren_count_(0), last_was_eol_(true),
+ has_previous_(false),
+ previous_paren_count_(0),
+ previous_was_eol_(false)
+ {
+ separators_.set('\r');
+ separators_.set('\n');
+ separators_.set(' ');
+ separators_.set('\t');
+ separators_.set('(');
+ separators_.set(')');
+ separators_.set('"');
+ esc_separators_.set('\r');
+ esc_separators_.set('\n');
+ }
+
+ // A helper method to skip possible comments toward the end of EOL or EOF.
+ // commonly used by state classes. It returns the corresponding "end-of"
+ // character in case it's a comment; otherwise it simply returns the
+ // current character.
+ int skipComment(int c, bool escaped = false) {
+ if (c == ';' && !escaped) {
+ while (true) {
+ c = source_->getChar();
+ if (c == '\n' || c == InputSource::END_OF_STREAM) {
+ return (c);
+ }
+ }
+ }
+ return (c);
+ }
+
+ bool isTokenEnd(int c, bool escaped) {
+ // Special case of EOF (end of stream); this is not in the bitmaps
+ if (c == InputSource::END_OF_STREAM) {
+ return (true);
+ }
+ // In this implementation we only ensure the behavior for unsigned
+ // range of characters, so we restrict the range of the values up to
+ // 0x7f = 127
+ return (escaped ? esc_separators_.test(c & 0x7f) :
+ separators_.test(c & 0x7f));
+ }
+
+ void setTotalSize() {
+ assert(source_ != NULL);
+ if (total_size_ != SOURCE_SIZE_UNKNOWN) {
+ const size_t current_size = source_->getSize();
+ if (current_size != SOURCE_SIZE_UNKNOWN) {
+ total_size_ += current_size;
+ } else {
+ total_size_ = SOURCE_SIZE_UNKNOWN;
+ }
+ }
+ }
+
+ std::vector<InputSourcePtr> sources_;
+ InputSource* source_; // current source (NULL if sources_ is empty)
+ MasterToken token_; // currently recognized token (set by a state)
+ std::vector<char> data_; // placeholder for string data
+
+ // Keep track of the total size of all sources and characters that have
+ // been read from sources already popped.
+ size_t total_size_; // accumulated size (# of chars) of sources
+ size_t popped_size_; // total size of sources that have been popped
+
+ // These are used in states, and defined here only as a placeholder.
+ // The main lexer class does not need these members.
+ size_t paren_count_; // nest count of the parentheses
+ bool last_was_eol_; // whether the lexer just passed an end-of-line
+
+ // Bitmaps that gives whether a given (positive) character should be
+ // considered a separator of a string/number token. The esc_ version
+ // is a subset of the other, excluding characters that can be ignored
+ // if escaped by a backslash. See isTokenEnd() for the bitmap size.
+ std::bitset<128> separators_;
+ std::bitset<128> esc_separators_;
+
+ // These are to allow restoring state before previous token.
+ bool has_previous_;
+ size_t previous_paren_count_;
+ bool previous_was_eol_;
+};
+
+MasterLexer::MasterLexer() : impl_(new MasterLexerImpl) {
+}
+
+MasterLexer::~MasterLexer() {
+ delete impl_;
+}
+
+bool
+MasterLexer::pushSource(const char* filename, std::string* error) {
+ if (filename == NULL) {
+ isc_throw(InvalidParameter,
+ "NULL filename for MasterLexer::pushSource");
+ }
+ try {
+ impl_->sources_.push_back(InputSourcePtr(new InputSource(filename)));
+ } catch (const InputSource::OpenError& ex) {
+ if (error != NULL) {
+ *error = ex.what();
+ }
+ return (false);
+ }
+
+ impl_->source_ = impl_->sources_.back().get();
+ impl_->has_previous_ = false;
+ impl_->last_was_eol_ = true;
+ impl_->setTotalSize();
+ return (true);
+}
+
+void
+MasterLexer::pushSource(std::istream& input) {
+ try {
+ impl_->sources_.push_back(InputSourcePtr(new InputSource(input)));
+ } catch (const InputSource::OpenError& ex) {
+ // Convert the "internal" exception to public one.
+ isc_throw(Unexpected, "Failed to push a stream to lexer: " <<
+ ex.what());
+ }
+ impl_->source_ = impl_->sources_.back().get();
+ impl_->has_previous_ = false;
+ impl_->last_was_eol_ = true;
+ impl_->setTotalSize();
+}
+
+void
+MasterLexer::popSource() {
+ if (impl_->sources_.empty()) {
+ isc_throw(InvalidOperation,
+ "MasterLexer::popSource on an empty source");
+ }
+ impl_->popped_size_ += impl_->source_->getPosition();
+ impl_->sources_.pop_back();
+ impl_->source_ = impl_->sources_.empty() ? NULL :
+ impl_->sources_.back().get();
+ impl_->has_previous_ = false;
+}
+
+size_t
+MasterLexer::getSourceCount() const {
+ return (impl_->sources_.size());
+}
+
+std::string
+MasterLexer::getSourceName() const {
+ if (impl_->sources_.empty()) {
+ return (std::string());
+ }
+ return (impl_->sources_.back()->getName());
+}
+
+size_t
+MasterLexer::getSourceLine() const {
+ if (impl_->sources_.empty()) {
+ return (0);
+ }
+ return (impl_->sources_.back()->getCurrentLine());
+}
+
+size_t
+MasterLexer::getTotalSourceSize() const {
+ return (impl_->total_size_);
+}
+
+size_t
+MasterLexer::getPosition() const {
+ size_t position = impl_->popped_size_;
+ BOOST_FOREACH(InputSourcePtr& src, impl_->sources_) {
+ position += src->getPosition();
+ }
+ return (position);
+}
+
+const MasterToken&
+MasterLexer::getNextToken(Options options) {
+ if (impl_->source_ == NULL) {
+ isc_throw(isc::InvalidOperation, "No source to read tokens from");
+ }
+ // Store the current state so we can restore it in ungetToken
+ impl_->previous_paren_count_ = impl_->paren_count_;
+ impl_->previous_was_eol_ = impl_->last_was_eol_;
+ impl_->source_->mark();
+ impl_->has_previous_ = true;
+ // Reset the token now. This is to check a token was actually produced.
+ // This is debugging aid.
+ impl_->token_ = MasterToken(MasterToken::NO_TOKEN_PRODUCED);
+ // And get the token
+
+ // This actually handles EOF internally too.
+ const State* state = State::start(*this, options);
+ if (state != NULL) {
+ state->handle(*this);
+ }
+ // Make sure a token was produced. Since this Can Not Happen, we assert
+ // here instead of throwing.
+ assert(impl_->token_.getType() != MasterToken::ERROR ||
+ impl_->token_.getErrorCode() != MasterToken::NO_TOKEN_PRODUCED);
+ return (impl_->token_);
+}
+
+namespace {
+inline MasterLexer::Options
+optionsForTokenType(MasterToken::Type expect) {
+ switch (expect) {
+ case MasterToken::STRING:
+ return (MasterLexer::NONE);
+ case MasterToken::QSTRING:
+ return (MasterLexer::QSTRING);
+ case MasterToken::NUMBER:
+ return (MasterLexer::NUMBER);
+ default:
+ isc_throw(InvalidParameter,
+ "expected type for getNextToken not supported: " << expect);
+ }
+}
+}
+
+const MasterToken&
+MasterLexer::getNextToken(MasterToken::Type expect, bool eol_ok) {
+ // Get the next token, specifying an appropriate option corresponding to
+ // the expected type. The result should be set in impl_->token_.
+ getNextToken(optionsForTokenType(expect));
+
+ if (impl_->token_.getType() == MasterToken::ERROR) {
+ if (impl_->token_.getErrorCode() == MasterToken::NUMBER_OUT_OF_RANGE) {
+ ungetToken();
+ }
+ throw LexerError(__FILE__, __LINE__, impl_->token_);
+ }
+
+ const bool is_eol_like =
+ (impl_->token_.getType() == MasterToken::END_OF_LINE ||
+ impl_->token_.getType() == MasterToken::END_OF_FILE);
+ if (eol_ok && is_eol_like) {
+ return (impl_->token_);
+ }
+ if (impl_->token_.getType() == MasterToken::STRING &&
+ expect == MasterToken::QSTRING) {
+ return (impl_->token_);
+ }
+ if (impl_->token_.getType() != expect) {
+ ungetToken();
+ if (is_eol_like) {
+ throw LexerError(__FILE__, __LINE__,
+ MasterToken(MasterToken::UNEXPECTED_END));
+ }
+ assert(expect == MasterToken::NUMBER);
+ throw LexerError(__FILE__, __LINE__,
+ MasterToken(MasterToken::BAD_NUMBER));
+ }
+
+ return (impl_->token_);
+}
+
+void
+MasterLexer::ungetToken() {
+ if (impl_->has_previous_) {
+ impl_->has_previous_ = false;
+ impl_->source_->ungetAll();
+ impl_->last_was_eol_ = impl_->previous_was_eol_;
+ impl_->paren_count_ = impl_->previous_paren_count_;
+ } else {
+ isc_throw(isc::InvalidOperation, "No token to unget ready");
+ }
+}
+
+namespace {
+const char* const error_text[] = {
+ "lexer not started", // NOT_STARTED
+ "unbalanced parentheses", // UNBALANCED_PAREN
+ "unexpected end of input", // UNEXPECTED_END
+ "unbalanced quotes", // UNBALANCED_QUOTES
+ "no token produced", // NO_TOKEN_PRODUCED
+ "number out of range", // NUMBER_OUT_OF_RANGE
+ "not a valid number", // BAD_NUMBER
+ "unexpected quotes" // UNEXPECTED_QUOTES
+};
+const size_t error_text_max_count = sizeof(error_text) / sizeof(error_text[0]);
+} // end unnamed namespace
+
+std::string
+MasterToken::getErrorText() const {
+ if (type_ != ERROR) {
+ isc_throw(InvalidOperation,
+ "MasterToken::getErrorText() for non error type");
+ }
+
+ // The class integrity ensures the following:
+ assert(val_.error_code_ < error_text_max_count);
+ return (error_text[val_.error_code_]);
+}
+
+namespace master_lexer_internal {
+// Below we implement state classes for state transitions of MasterLexer.
+// Note that these need to be defined here so that they can refer to
+// the details of MasterLexerImpl.
+
+bool
+State::wasLastEOL(const MasterLexer& lexer) const {
+ return (lexer.impl_->last_was_eol_);
+}
+
+const MasterToken&
+State::getToken(const MasterLexer& lexer) const {
+ return (lexer.impl_->token_);
+}
+
+size_t
+State::getParenCount(const MasterLexer& lexer) const {
+ return (lexer.impl_->paren_count_);
+}
+
+namespace {
+class CRLF : public State {
+public:
+ CRLF() {}
+ virtual ~CRLF() {} // see the base class for the destructor
+ virtual void handle(MasterLexer& lexer) const {
+ // We've just seen '\r'. If this is part of a sequence of '\r\n',
+ // we combine them as a single END-OF-LINE. Otherwise we treat the
+ // single '\r' as an EOL and continue tokenization from the character
+ // immediately after '\r'. One tricky case is that there's a comment
+ // between '\r' and '\n'. This implementation combines these
+ // characters and treats them as a single EOL (the behavior derived
+ // from BIND 9). Technically this may not be correct, but in practice
+ // the caller wouldn't distinguish this case from the case it has
+ // two EOLs, so we simplify the process.
+ const int c = getLexerImpl(lexer)->skipComment(
+ getLexerImpl(lexer)->source_->getChar());
+ if (c != '\n') {
+ getLexerImpl(lexer)->source_->ungetChar();
+ }
+ getLexerImpl(lexer)->token_ = MasterToken(MasterToken::END_OF_LINE);
+ getLexerImpl(lexer)->last_was_eol_ = true;
+ }
+};
+
+class String : public State {
+public:
+ String() {}
+ virtual ~String() {} // see the base class for the destructor
+ virtual void handle(MasterLexer& lexer) const;
+};
+
+class QString : public State {
+public:
+ QString() {}
+ virtual ~QString() {} // see the base class for the destructor
+ virtual void handle(MasterLexer& lexer) const;
+};
+
+class Number : public State {
+public:
+ Number() {}
+ virtual ~Number() {}
+ virtual void handle(MasterLexer& lexer) const;
+};
+
+// We use a common instance of a each state in a singleton-like way to save
+// construction overhead. They are not singletons in its strict sense as
+// we don't prohibit direct construction of these objects. But that doesn't
+// matter much anyway, because the definitions are completely hidden within
+// this file.
+const CRLF CRLF_STATE;
+const String STRING_STATE;
+const QString QSTRING_STATE;
+const Number NUMBER_STATE;
+} // end unnamed namespace
+
+const State&
+State::getInstance(ID state_id) {
+ switch (state_id) {
+ case CRLF:
+ return (CRLF_STATE);
+ case String:
+ return (STRING_STATE);
+ case QString:
+ return (QSTRING_STATE);
+ case Number:
+ return (NUMBER_STATE);
+ }
+
+ // This is a bug of the caller, and this method is only expected to be
+ // used by tests, so we just forcefully make it fail by asserting the
+ // condition.
+ assert(false);
+ return (STRING_STATE); // a dummy return, to silence some compilers.
+}
+
+const State*
+State::start(MasterLexer& lexer, MasterLexer::Options options) {
+ // define some shortcuts
+ MasterLexer::MasterLexerImpl& lexerimpl = *lexer.impl_;
+ size_t& paren_count = lexerimpl.paren_count_;
+
+ // Note: the if-else in the loop is getting complicated. When we complete
+ // #2374, revisit the organization to see if we need a fundamental
+ // refactoring.
+ while (true) {
+ const int c = lexerimpl.skipComment(lexerimpl.source_->getChar());
+ if (c == InputSource::END_OF_STREAM) {
+ lexerimpl.last_was_eol_ = false;
+ if (paren_count != 0) {
+ lexerimpl.token_ = MasterToken(MasterToken::UNBALANCED_PAREN);
+ paren_count = 0; // reset to 0; this helps in lenient mode.
+ return (NULL);
+ }
+ lexerimpl.token_ = MasterToken(MasterToken::END_OF_FILE);
+ return (NULL);
+ } else if (c == ' ' || c == '\t') {
+ // If requested and we are not in (), recognize the initial space.
+ if (lexerimpl.last_was_eol_ && paren_count == 0 &&
+ (options & MasterLexer::INITIAL_WS) != 0) {
+ lexerimpl.last_was_eol_ = false;
+ lexerimpl.token_ = MasterToken(MasterToken::INITIAL_WS);
+ return (NULL);
+ }
+ } else if (c == '\n') {
+ lexerimpl.last_was_eol_ = true;
+ if (paren_count == 0) { // we don't recognize EOL if we are in ()
+ lexerimpl.token_ = MasterToken(MasterToken::END_OF_LINE);
+ return (NULL);
+ }
+ } else if (c == '\r') {
+ if (paren_count == 0) { // check if we are in () (see above)
+ return (&CRLF_STATE);
+ }
+ } else if (c == '"') {
+ if ((options & MasterLexer::QSTRING) != 0) {
+ lexerimpl.last_was_eol_ = false;
+ return (&QSTRING_STATE);
+ } else {
+ lexerimpl.token_ = MasterToken(MasterToken::UNEXPECTED_QUOTES);
+ return (NULL);
+ }
+ } else if (c == '(') {
+ lexerimpl.last_was_eol_ = false;
+ ++paren_count;
+ } else if (c == ')') {
+ lexerimpl.last_was_eol_ = false;
+ if (paren_count == 0) {
+ lexerimpl.token_ = MasterToken(MasterToken::UNBALANCED_PAREN);
+ return (NULL);
+ }
+ --paren_count;
+ } else if ((options & MasterLexer::NUMBER) != 0 &&isdigit(c)) {
+ lexerimpl.last_was_eol_ = false;
+ // this character will be handled in the number state
+ lexerimpl.source_->ungetChar();
+ return (&NUMBER_STATE);
+ } else {
+ // this character will be handled in the string state
+ lexerimpl.source_->ungetChar();
+ lexerimpl.last_was_eol_ = false;
+ return (&STRING_STATE);
+ }
+ // no code should be here; we just continue the loop.
+ }
+}
+
+void
+String::handle(MasterLexer& lexer) const {
+ std::vector<char>& data = getLexerImpl(lexer)->data_;
+ data.clear();
+
+ bool escaped = false;
+ while (true) {
+ const int c = getLexerImpl(lexer)->skipComment(
+ getLexerImpl(lexer)->source_->getChar(), escaped);
+
+ if (getLexerImpl(lexer)->isTokenEnd(c, escaped)) {
+ getLexerImpl(lexer)->source_->ungetChar();
+ // make sure it nul-terminated as a c-str (excluded from token
+ // data).
+ data.push_back('\0');
+ getLexerImpl(lexer)->token_ =
+ MasterToken(&data.at(0), data.size() - 1);
+ return;
+ }
+ escaped = (c == '\\' && !escaped);
+ data.push_back(c);
+ }
+}
+
+void
+QString::handle(MasterLexer& lexer) const {
+ MasterToken& token = getLexerImpl(lexer)->token_;
+ std::vector<char>& data = getLexerImpl(lexer)->data_;
+ data.clear();
+
+ bool escaped = false;
+ while (true) {
+ const int c = getLexerImpl(lexer)->source_->getChar();
+ if (c == InputSource::END_OF_STREAM) {
+ token = MasterToken(MasterToken::UNEXPECTED_END);
+ return;
+ } else if (c == '"') {
+ if (escaped) {
+ // found escaped '"'. overwrite the preceding backslash.
+ assert(!data.empty());
+ escaped = false;
+ data.back() = '"';
+ } else {
+ // make sure it nul-terminated as a c-str (excluded from token
+ // data). This also simplifies the case of an empty string.
+ data.push_back('\0');
+ token = MasterToken(&data.at(0), data.size() - 1, true);
+ return;
+ }
+ } else if (c == '\n' && !escaped) {
+ getLexerImpl(lexer)->source_->ungetChar();
+ token = MasterToken(MasterToken::UNBALANCED_QUOTES);
+ return;
+ } else {
+ escaped = (c == '\\' && !escaped);
+ data.push_back(c);
+ }
+ }
+}
+
+void
+Number::handle(MasterLexer& lexer) const {
+ MasterToken& token = getLexerImpl(lexer)->token_;
+
+ // It may yet turn out to be a string, so we first
+ // collect all the data
+ bool digits_only = true;
+ std::vector<char>& data = getLexerImpl(lexer)->data_;
+ data.clear();
+ bool escaped = false;
+
+ while (true) {
+ const int c = getLexerImpl(lexer)->skipComment(
+ getLexerImpl(lexer)->source_->getChar(), escaped);
+ if (getLexerImpl(lexer)->isTokenEnd(c, escaped)) {
+ getLexerImpl(lexer)->source_->ungetChar();
+ // We need to close the string whether it's digits-only (for
+ // lexical_cast) or not (see String::handle()).
+ data.push_back('\0');
+ if (digits_only) {
+ try {
+ const uint32_t number32 =
+ boost::lexical_cast<uint32_t, const char*>(&data[0]);
+ token = MasterToken(number32);
+ } catch (const boost::bad_lexical_cast&) {
+ // Since we already know we have only digits,
+ // range should be the only possible problem.
+ token = MasterToken(MasterToken::NUMBER_OUT_OF_RANGE);
+ }
+ } else {
+ token = MasterToken(&data.at(0), data.size() - 1);
+ }
+ return;
+ }
+ if (!isdigit(c)) {
+ digits_only = false;
+ }
+ escaped = (c == '\\' && !escaped);
+ data.push_back(c);
+ }
+}
+
+} // namespace master_lexer_internal
+
+} // end of namespace dns
+} // end of namespace isc
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-13 21:24:38 +0000