/*
 * 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/.
 *
 * Copyright 2010-2014 Danny Robson <danny@nerdcruft.net>
 */


#include "backtrace.hpp"

#include "debug.hpp"
#include "exe.hpp"
#include "io.hpp"
#include "cast.hpp"

#include <sstream>
#include <cstdio>
#include <cstdlib>
#include <execinfo.h>
#include <memory>


///////////////////////////////////////////////////////////////////////////////
debug::backtrace::backtrace (void):
    m_frames (DEFAULT_DEPTH)
{
    size_t last;
    size_t size = m_frames.size ();

    while ((last = ::backtrace (&m_frames[0], util::cast::lossless <int> (m_frames.size ()))) == size)
        m_frames.resize (size = m_frames.size () * 2);

    CHECK_GT (last, 0u);
    m_frames.resize (last);
}


///////////////////////////////////////////////////////////////////////////////
static std::string
addr2line (const void *addr)
{
#if defined(ADDR2LINE)
    using pstream_t = std::unique_ptr<FILE,decltype(&::pclose)>;

    std::ostringstream cmd;
    cmd << ADDR2LINE << " -e " << util::image_path () << ' ' << std::hex << addr;

    pstream_t stream (
        ::popen (cmd.str ().c_str (), "r"),
        ::pclose
    );

    // inefficient to copy from vector to string, but it's not a high priority path
    auto data = util::slurp<char> (stream.get ());
    return std::string (data.cbegin (), data.cend ());

#else
    return "";
#endif
}


///////////////////////////////////////////////////////////////////////////////
std::ostream&
debug::operator <<(std::ostream &os, const debug::backtrace &rhs) {
    auto const &frames = rhs.frames ();

    // We don't use the array form of unique_ptr as clang fails on ambigious constructors
    typedef std::unique_ptr<char *, decltype(&std::free)> str_t;
    str_t names (backtrace_symbols (frames.data (), util::cast::lossless <int> (frames.size ())), ::free);

    for (unsigned int i = 0; i < frames.size (); ++i)
        os << frames[i] << '\t' << names.get()[i] << '\t' << addr2line (frames[i]);

    return os;
}