minix/external/bsd/kyua-cli/dist/utils/config/parser.cpp

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// Copyright 2012 Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// * Neither the name of Google Inc. nor the names of its contributors
// may be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "utils/config/parser.hpp"
#include <lutok/exceptions.hpp>
#include <lutok/operations.hpp>
#include <lutok/stack_cleaner.hpp>
#include <lutok/state.ipp>
#include "utils/config/exceptions.hpp"
#include "utils/config/lua_module.hpp"
#include "utils/config/tree.ipp"
#include "utils/logging/macros.hpp"
#include "utils/noncopyable.hpp"
namespace config = utils::config;
// History of configuration file versions:
//
// 2 - Changed the syntax() call to take only a version number, instead of the
// word 'config' as the first argument and the version as the second one.
// Files now start with syntax(2) instead of syntax('config', 1).
//
// 1 - Initial version.
/// Internal implementation of the parser.
struct utils::config::parser::impl : utils::noncopyable {
/// Pointer to the parent parser. Needed for callbacks.
parser* _parent;
/// The Lua state used by this parser to process the configuration file.
lutok::state _state;
/// The tree to be filed in by the configuration parameters, as provided by
/// the caller.
config::tree& _tree;
/// Whether syntax() has been called or not.
bool _syntax_called;
/// Constructs a new implementation.
///
/// \param parent_ Pointer to the class being constructed.
/// \param config_tree_ The configuration tree provided by the user.
impl(parser* const parent_, tree& config_tree_) :
_parent(parent_), _tree(config_tree_), _syntax_called(false)
{
}
friend void lua_syntax(lutok::state&);
/// Callback executed by the Lua syntax() function.
///
/// \param syntax_version The syntax format version as provided by the
/// configuration file in the call to syntax().
void
syntax_callback(const int syntax_version)
{
if (_syntax_called)
throw syntax_error("syntax() can only be called once");
_syntax_called = true;
// Allow the parser caller to populate the tree with its own schema
// depending on the format/version combination.
_parent->setup(_tree, syntax_version);
// Export the config module to the Lua state so that all global variable
// accesses are redirected to the configuration tree.
config::redirect(_state, _tree);
}
};
namespace {
/// Implementation of the Lua syntax() function.
///
/// The syntax() function has to be called by configuration files as the very
/// first thing they do. Once called, this function populates the configuration
/// tree based on the syntax version and then continues to process the rest of
/// the file.
///
/// \pre state(-2) The syntax format name, if a v1 file.
/// \pre state(-1) The syntax format version.
///
/// \param state The Lua state to operate in.
///
/// \return The number of results pushed onto the stack; always 0.
static int
lua_syntax(lutok::state& state)
{
if (!state.is_number(-1))
throw config::value_error("Last argument to syntax must be a number");
const int syntax_version = state.to_integer(-1);
if (syntax_version == 1) {
if (state.get_top() != 2)
throw config::value_error("Version 1 files need two arguments to "
"syntax()");
if (!state.is_string(-2) || state.to_string(-2) != "config")
throw config::value_error("First argument to syntax must be "
"'config' for version 1 files");
} else {
if (state.get_top() != 1)
throw config::value_error("syntax() only takes one argument");
}
state.get_global("_config_parser");
config::parser::impl* impl = *state.to_userdata< config::parser::impl* >();
state.pop(1);
impl->syntax_callback(syntax_version);
return 0;
}
} // anonymous namespace
/// Constructs a new parser.
///
/// \param [in,out] config_tree The configuration tree into which the values set
/// in the configuration file will be stored.
config::parser::parser(tree& config_tree) :
_pimpl(new impl(this, config_tree))
{
lutok::stack_cleaner cleaner(_pimpl->_state);
_pimpl->_state.push_cxx_function(lua_syntax);
_pimpl->_state.set_global("syntax");
*_pimpl->_state.new_userdata< config::parser::impl* >() = _pimpl.get();
_pimpl->_state.set_global("_config_parser");
}
/// Destructor.
config::parser::~parser(void)
{
}
/// Parses a configuration file.
///
/// \post The tree registered during the construction of this class is updated
/// to contain the values read from the configuration file. If the processing
/// fails, the state of the output tree is undefined.
///
/// \param file The path to the file to process.
///
/// \throw syntax_error If there is any problem processing the file.
void
config::parser::parse(const fs::path& file)
{
try {
lutok::do_file(_pimpl->_state, file.str());
} catch (const lutok::error& e) {
throw syntax_error(e.what());
}
if (!_pimpl->_syntax_called)
throw syntax_error("No syntax defined (no call to syntax() found)");
}