1 files changed, 221 insertions, 0 deletions
diff --git a/src/lib/dns/master_lexer_inputsource.cc b/src/lib/dns/master_lexer_inputsource.cc
new file mode 100644
index 0000000..841fc6c
--- /dev/null
+++ b/src/lib/dns/master_lexer_inputsource.cc
@@ -0,0 +1,221 @@
+// Copyright (C) 2012-2015 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 <dns/master_lexer_inputsource.h>
+#include <dns/master_lexer.h>
+
+#include <istream>
+#include <iostream>
+#include <cassert>
+#include <cerrno>
+#include <cstring>
+
+namespace isc {
+namespace dns {
+namespace master_lexer_internal {
+
+namespace { // unnamed namespace
+
+std::string
+createStreamName(const std::istream& input_stream) {
+     std::stringstream ss;
+     ss << "stream-" << &input_stream;
+     return (ss.str());
+}
+
+size_t
+getStreamSize(std::istream& is) {
+    errno = 0;                  // see below
+    is.seekg(0, std::ios_base::end);
+    if (is.bad()) {
+        // This means the istream has an integrity error.  It doesn't make
+        // sense to continue from this point, so we treat it as a fatal error.
+        isc_throw(InputSource::OpenError,
+                  "failed to seek end of input source");
+    } else if (is.fail() || errno != 0) {
+        // This is an error specific to seekg().  There can be several
+        // reasons, but the most likely cause in this context is that the
+        // stream is associated with a special type of file such as a pipe.
+        // In this case, it's more likely that other main operations of
+        // the input source work fine, so we continue with just setting
+        // the stream size to "unknown".
+        //
+        // (At least some versions of) Solaris + SunStudio shows deviant
+        // behavior here: seekg() apparently calls lseek(2) internally, but
+        // even if it fails it doesn't set the error bits of istream. That will
+        // confuse the rest of this function, so, as a heuristic workaround
+        // we check errno and handle any non 0 value as fail().
+        is.clear();   // clear this error not to confuse later ops.
+        return (MasterLexer::SOURCE_SIZE_UNKNOWN);
+    }
+    const std::streampos len = is.tellg();
+    size_t ret = len;
+    if (len == static_cast<std::streampos>(-1)) { // cast for some compilers
+        if (!is.fail()) {
+            // tellg() returns -1 if istream::fail() would be true, but it's
+            // not guaranteed that it shouldn't be returned in other cases.
+            // In fact, with the combination of SunStudio and stlport,
+            // a stringstream created by the default constructor showed that
+            // behavior.  We treat such cases as an unknown size.
+            ret = MasterLexer::SOURCE_SIZE_UNKNOWN;
+        } else {
+            isc_throw(InputSource::OpenError, "failed to get input size");
+        }
+    }
+    is.seekg(0, std::ios::beg);
+    if (is.fail()) {
+        isc_throw(InputSource::OpenError,
+                  "failed to seek beginning of input source");
+    }
+    assert(len >= 0 || ret == MasterLexer::SOURCE_SIZE_UNKNOWN);
+    return (ret);
+}
+
+} // end of unnamed namespace
+
+// Explicit definition of class static constant.  The value is given in the
+// declaration so it's not needed here.
+const int InputSource::END_OF_STREAM;
+
+InputSource::InputSource(std::istream& input_stream) :
+    at_eof_(false),
+    line_(1),
+    saved_line_(line_),
+    buffer_pos_(0),
+    total_pos_(0),
+    name_(createStreamName(input_stream)),
+    input_(input_stream),
+    input_size_(getStreamSize(input_))
+{}
+
+namespace {
+// A helper to initialize InputSource::input_ in the member initialization
+// list.
+std::istream&
+openFileStream(std::ifstream& file_stream, const char* filename) {
+    errno = 0;
+    file_stream.open(filename);
+    if (file_stream.fail()) {
+        std::string error_txt("Error opening the input source file: ");
+        error_txt += filename;
+        if (errno != 0) {
+            error_txt += "; possible cause: ";
+            error_txt += std::strerror(errno);
+        }
+        isc_throw(InputSource::OpenError, error_txt);
+    }
+
+    return (file_stream);
+}
+}
+
+InputSource::InputSource(const char* filename) :
+    at_eof_(false),
+    line_(1),
+    saved_line_(line_),
+    buffer_pos_(0),
+    total_pos_(0),
+    name_(filename),
+    input_(openFileStream(file_stream_, filename)),
+    input_size_(getStreamSize(input_))
+{}
+
+InputSource::~InputSource()
+{
+    if (file_stream_.is_open()) {
+        file_stream_.close();
+    }
+}
+
+int
+InputSource::getChar() {
+    if (buffer_pos_ == buffer_.size()) {
+        // We may have reached EOF at the last call to
+        // getChar(). at_eof_ will be set then. We then simply return
+        // early.
+        if (at_eof_) {
+            return (END_OF_STREAM);
+        }
+        // We are not yet at EOF. Read from the stream.
+        const int c = input_.get();
+        // Have we reached EOF now? If so, set at_eof_ and return early,
+        // but don't modify buffer_pos_ (which should still be equal to
+        // the size of buffer_).
+        if (input_.eof()) {
+            at_eof_ = true;
+            return (END_OF_STREAM);
+        }
+        // This has to come after the .eof() check as some
+        // implementations seem to check the eofbit also in .fail().
+        if (input_.fail()) {
+            isc_throw(MasterLexer::ReadError,
+                      "Error reading from the input stream: " << getName());
+        }
+        buffer_.push_back(c);
+    }
+
+    const int c = buffer_[buffer_pos_];
+    ++buffer_pos_;
+    ++total_pos_;
+    if (c == '\n') {
+        ++line_;
+    }
+
+    return (c);
+}
+
+void
+InputSource::ungetChar() {
+    if (at_eof_) {
+        at_eof_ = false;
+    } else if (buffer_pos_ == 0) {
+        isc_throw(UngetBeforeBeginning,
+                  "Cannot skip before the start of buffer");
+    } else {
+        --buffer_pos_;
+        --total_pos_;
+        if (buffer_[buffer_pos_] == '\n') {
+            --line_;
+        }
+    }
+}
+
+void
+InputSource::ungetAll() {
+    assert(total_pos_ >= buffer_pos_);
+    total_pos_ -= buffer_pos_;
+    buffer_pos_ = 0;
+    line_ = saved_line_;
+    at_eof_ = false;
+}
+
+void
+InputSource::saveLine() {
+    saved_line_ = line_;
+}
+
+void
+InputSource::compact() {
+    if (buffer_pos_ == buffer_.size()) {
+        buffer_.clear();
+    } else {
+        buffer_.erase(buffer_.begin(), buffer_.begin() + buffer_pos_);
+    }
+
+    buffer_pos_ = 0;
+}
+
+void
+InputSource::mark() {
+    saveLine();
+    compact();
+}
+
+} // namespace master_lexer_internal
+} // namespace dns
+} // namespace isc