source: git/src/cavernlog.cc @ c606770

/* cavernlog.cc
 * Run cavern inside an Aven window
 *
 * Copyright (C) 2005-2022 Olly Betts
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

#include <config.h>

#include "aven.h"
#include "cavernlog.h"
#include "filename.h"
#include "mainfrm.h"
#include "message.h"

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>

// For select():
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

#include <wx/process.h>

#define GVIM_COMMAND "gvim +'call cursor($l,$c)' $f"
#define VIM_COMMAND "x-terminal-emulator -e vim +'call cursor($l,$c)' $f"
#define NVIM_COMMAND "x-terminal-emulator -e nvim +'call cursor($l,$c)' $f"
#define GEDIT_COMMAND "gedit $f +$l:$c"
// Pluma currently ignores the column, but include it assuming some future
// version will add support.
#define PLUMA_COMMAND "pluma +$l:$c $f"
#define EMACS_COMMAND "x-terminal-emulator -e emacs +$l:$c $f"
#define NANO_COMMAND "x-terminal-emulator -e nano +$l,$c $f"
#define JED_COMMAND "x-terminal-emulator -e jed $f -g $l"
#define KATE_COMMAND "kate -l $l -c $c $f"

#ifdef __WXMSW__
# define DEFAULT_EDITOR_COMMAND "notepad $f"
#elif defined __WXMAC__
# define DEFAULT_EDITOR_COMMAND "open -t $f"
#else
# define DEFAULT_EDITOR_COMMAND VIM_COMMAND
#endif

enum { LOG_REPROCESS = 1234, LOG_SAVE = 1235 };

static const wxString badutf8_html(
    wxT("<span style=\"color:white;background-color:red;\">&#xfffd;</span>"));
static const wxString badutf8(wxUniChar(0xfffd));

// New event type for passing a chunk of cavern output from the worker thread
// to the main thread (or from the idle event handler if we're not using
// threads).
class CavernOutputEvent;

wxDEFINE_EVENT(wxEVT_CAVERN_OUTPUT, CavernOutputEvent);

class CavernOutputEvent : public wxEvent {
  public:
    char buf[1000];
    int len;
    CavernOutputEvent() : wxEvent(0, wxEVT_CAVERN_OUTPUT), len(0) { }

    wxEvent * Clone() const {
        CavernOutputEvent * e = new CavernOutputEvent();
        e->len = len;
        if (len > 0) memcpy(e->buf, buf, len);
        return e;
    }
};

#ifdef CAVERNLOG_USE_THREADS
class CavernThread : public wxThread {
  protected:
    virtual ExitCode Entry();

    CavernLogWindow *handler;

    wxInputStream * in;

  public:
    CavernThread(CavernLogWindow *handler_, wxInputStream * in_)
        : wxThread(wxTHREAD_DETACHED), handler(handler_), in(in_) { }

    ~CavernThread() {
        wxCriticalSectionLocker enter(handler->thread_lock);
        handler->thread = NULL;
    }
};

wxThread::ExitCode
CavernThread::Entry()
{
    while (true) {
        CavernOutputEvent * e = new CavernOutputEvent();
        in->Read(e->buf, sizeof(e->buf));
        size_t n = in->LastRead();
        if (n == 0 || TestDestroy()) {
            delete e;
            return (wxThread::ExitCode)0;
        }
        if (n == 1 && e->buf[0] == '\n') {
            // Don't send an event with just a blank line in.
            in->Read(e->buf + 1, sizeof(e->buf) - 1);
            n += in->LastRead();
            if (TestDestroy()) {
                delete e;
                return (wxThread::ExitCode)0;
            }
        }
        e->len = n;
        handler->QueueEvent(e);
    }
}

#else

void
CavernLogWindow::OnIdle(wxIdleEvent& event)
{
    if (cavern_out == NULL) return;

    wxInputStream * in = cavern_out->GetInputStream();

    if (!in->CanRead()) {
        // Avoid a tight busy-loop on idle events.
        wxMilliSleep(10);
    }
    if (in->CanRead()) {
        CavernOutputEvent * e = new CavernOutputEvent();
        in->Read(e->buf, sizeof(e->buf));
        size_t n = in->LastRead();
        if (n == 0) {
            delete e;
            return;
        }
        e->len = n;
        QueueEvent(e);
    }

    event.RequestMore();
}
#endif

BEGIN_EVENT_TABLE(CavernLogWindow, wxHtmlWindow)
    EVT_BUTTON(LOG_REPROCESS, CavernLogWindow::OnReprocess)
    EVT_BUTTON(LOG_SAVE, CavernLogWindow::OnSave)
    EVT_BUTTON(wxID_OK, CavernLogWindow::OnOK)
    EVT_COMMAND(wxID_ANY, wxEVT_CAVERN_OUTPUT, CavernLogWindow::OnCavernOutput)
#ifdef CAVERNLOG_USE_THREADS
    EVT_CLOSE(CavernLogWindow::OnClose)
#else
    EVT_IDLE(CavernLogWindow::OnIdle)
#endif
    EVT_END_PROCESS(wxID_ANY, CavernLogWindow::OnEndProcess)
END_EVENT_TABLE()

wxString escape_for_shell(wxString s, bool protect_dash)
{
#ifdef __WXMSW__
    // Correct quoting rules are insane:
    //
    // http://blogs.msdn.com/b/twistylittlepassagesallalike/archive/2011/04/23/everyone-quotes-arguments-the-wrong-way.aspx
    //
    // Thankfully wxExecute passes the command string to CreateProcess(), so
    // at least we don't need to quote for cmd.exe too.
    if (s.empty() || s.find_first_of(wxT(" \"\t\n\v")) != s.npos) {
        // Need to quote.
        s.insert(0, wxT('"'));
        for (size_t p = 1; p < s.size(); ++p) {
            size_t backslashes = 0;
            while (s[p] == wxT('\\')) {
                ++backslashes;
                if (++p == s.size()) {
                    // Escape all the backslashes, since they're before
                    // the closing quote we add below.
                    s.append(backslashes, wxT('\\'));
                    goto done;
                }
            }

            if (s[p] == wxT('"')) {
                // Escape any preceding backslashes and this quote.
                s.insert(p, backslashes + 1, wxT('\\'));
                p += backslashes + 1;
            }
        }
done:
        s.append(wxT('"'));
    }
#else
    size_t p = 0;
    if (protect_dash && !s.empty() && s[0u] == '-') {
        // If the filename starts with a '-', protect it from being
        // treated as an option by prepending "./".
        s.insert(0, wxT("./"));
        p = 2;
    }
    while (p < s.size()) {
        // Exclude a few safe characters which are common in filenames
        if (!isalnum((unsigned char)s[p]) && strchr("/._-", s[p]) == NULL) {
            s.insert(p, 1, wxT('\\'));
            ++p;
        }
        ++p;
    }
#endif
    return s;
}

wxString get_command_path(const wxChar * command_name)
{
#ifdef __WXMSW__
    wxString cmd;
    {
        DWORD len = 256;
        wchar_t *buf = NULL;
        while (1) {
            DWORD got;
            buf = (wchar_t*)osrealloc(buf, len * 2);
            got = GetModuleFileNameW(NULL, buf, len);
            if (got < len) break;
            len += len;
        }
        /* Strange Win32 nastiness - strip prefix "\\?\" if present */
        wchar_t *start = buf;
        if (wcsncmp(start, L"\\\\?\\", 4) == 0) start += 4;
        wchar_t * slash = wcsrchr(start, L'\\');
        if (slash) {
            cmd.assign(start, slash - start + 1);
        }
        osfree(buf);
    }
#else
    wxString cmd = wxString(msg_exepth(), wxConvUTF8);
#endif
    cmd += command_name;
    return cmd;
}

CavernLogWindow::CavernLogWindow(MainFrm * mainfrm_, const wxString & survey_, wxWindow * parent)
    : wxHtmlWindow(parent),
      mainfrm(mainfrm_),
      end(buf), survey(survey_)
{
    int fsize = parent->GetFont().GetPointSize();
    int sizes[7] = { fsize, fsize, fsize, fsize, fsize, fsize, fsize };
    SetFonts(wxString(), wxString(), sizes);
}

CavernLogWindow::~CavernLogWindow()
{
#ifdef CAVERNLOG_USE_THREADS
    if (thread) stop_thread();
#endif
    if (cavern_out) {
        wxEndBusyCursor();
        cavern_out->Detach();
    }
}

#ifdef CAVERNLOG_USE_THREADS
void
CavernLogWindow::stop_thread()
{
    // Killing the subprocess by its pid is theoretically racy, but in practice
    // it's not going to cause issues, and it's all the wxProcess API seems to
    // allow us to do.  If we don't kill the subprocess, we need to wait for it
    // to write out some output - there seems to be no way to do the equivalent
    // of select() with a timeout on a wxInputStream.
    //
    // The only alternative to this seems to be to do:
    //
    //     while (!s.CanRead()) {
    //         if (TestDestroy()) return (wxThread::ExitCode)0;
    //         wxMilliSleep(N);
    //     }
    //
    // But that makes the log window update sluggishly, and we're using a
    // worker thread precisely to try to avoid having to do dumb stuff like
    // this.
    wxProcess::Kill(cavern_out->GetPid());

    {
        wxCriticalSectionLocker enter(thread_lock);
        if (thread) {
            wxThreadError res;
            res = thread->Delete(NULL, wxTHREAD_WAIT_BLOCK);
            if (res != wxTHREAD_NO_ERROR) {
                // FIXME
            }
        }
    }

    // Wait for thread to complete.
    while (true) {
        {
            wxCriticalSectionLocker enter(thread_lock);
            if (!thread) break;
        }
        wxMilliSleep(1);
    }
}

void
CavernLogWindow::OnClose(wxCloseEvent &)
{
    if (thread) stop_thread();
    Destroy();
}
#endif

void
CavernLogWindow::OnLinkClicked(const wxHtmlLinkInfo &link)
{
    wxString href = link.GetHref();
    wxString title = link.GetTarget();
    size_t colon2 = href.rfind(wxT(':'));
    if (colon2 == wxString::npos)
        return;
    size_t colon = href.rfind(wxT(':'), colon2 - 1);
    if (colon == wxString::npos)
        return;
    wxString cmd;
    wxChar * p = wxGetenv(wxT("SURVEXEDITOR"));
    if (p) {
        cmd = p;
        if (!cmd.find(wxT("$f"))) {
            cmd += wxT(" $f");
        }
    } else {
        p = wxGetenv(wxT("VISUAL"));
        if (!p) p = wxGetenv(wxT("EDITOR"));
        if (!p) {
            cmd = wxT(DEFAULT_EDITOR_COMMAND);
        } else {
            cmd = p;
            if (cmd == "gvim") {
                cmd = wxT(GVIM_COMMAND);
            } else if (cmd == "vim") {
                cmd = wxT(VIM_COMMAND);
            } else if (cmd == "nvim") {
                cmd = wxT(NVIM_COMMAND);
            } else if (cmd == "gedit") {
                cmd = wxT(GEDIT_COMMAND);
            } else if (cmd == "pluma") {
                cmd = wxT(PLUMA_COMMAND);
            } else if (cmd == "emacs") {
                cmd = wxT(EMACS_COMMAND);
            } else if (cmd == "nano") {
                cmd = wxT(NANO_COMMAND);
            } else if (cmd == "jed") {
                cmd = wxT(JED_COMMAND);
            } else if (cmd == "kate") {
                cmd = wxT(KATE_COMMAND);
            } else {
                // Escape any $.
                cmd.Replace(wxT("$"), wxT("$$"));
                cmd += wxT(" $f");
            }
        }
    }
    size_t i = 0;
    while ((i = cmd.find(wxT('$'), i)) != wxString::npos) {
        if (++i >= cmd.size()) break;
        switch ((int)cmd[i]) {
            case wxT('$'):
                cmd.erase(i, 1);
                break;
            case wxT('f'): {
                wxString f = escape_for_shell(href.substr(0, colon), true);
                cmd.replace(i - 1, 2, f);
                i += f.size() - 1;
                break;
            }
            case wxT('t'): {
                wxString t = escape_for_shell(title);
                cmd.replace(i - 1, 2, t);
                i += t.size() - 1;
                break;
            }
            case wxT('l'): {
                wxString l = escape_for_shell(href.substr(colon + 1, colon2 - colon - 1));
                cmd.replace(i - 1, 2, l);
                i += l.size() - 1;
                break;
            }
            case wxT('c'): {
                wxString l;
                if (colon2 >= href.size() - 1)
                    l = wxT("0");
                else
                    l = escape_for_shell(href.substr(colon2 + 1));
                cmd.replace(i - 1, 2, l);
                i += l.size() - 1;
                break;
            }
            default:
                ++i;
        }
    }

    if (wxExecute(cmd, wxEXEC_ASYNC|wxEXEC_MAKE_GROUP_LEADER) >= 0)
        return;

    wxString m;
    // TRANSLATORS: %s is replaced by the command we attempted to run.
    m.Printf(wmsg(/*Couldn’t run external command: “%s”*/17), cmd.c_str());
    m += wxT(" (");
    m += wxString(strerror(errno), wxConvUTF8);
    m += wxT(')');
    wxGetApp().ReportError(m);
}

void
CavernLogWindow::process(const wxString &file)
{
    SetPage(wxString());
#ifdef CAVERNLOG_USE_THREADS
    if (thread) stop_thread();
#endif
    if (cavern_out) {
        cavern_out->Detach();
        cavern_out = NULL;
    } else {
        wxBeginBusyCursor();
    }

    SetFocus();
    filename = file;

    info_count = 0;
    link_count = 0;
    cur.resize(0);
    log_txt.resize(0);

#ifdef __WXMSW__
    SetEnvironmentVariable(wxT("SURVEX_UTF8"), wxT("1"));
#else
    setenv("SURVEX_UTF8", "1", 1);
#endif

    wxString escaped_file = escape_for_shell(file, true);
    wxString cmd = get_command_path(L"cavern");
    cmd = escape_for_shell(cmd, false);
    cmd += wxT(" -o ");
    cmd += escaped_file;
    cmd += wxT(' ');
    cmd += escaped_file;

    cavern_out = wxProcess::Open(cmd);
    if (!cavern_out) {
        wxString m;
        m.Printf(wmsg(/*Couldn’t run external command: “%s”*/17), cmd.c_str());
        m += wxT(" (");
        m += wxString(strerror(errno), wxConvUTF8);
        m += wxT(')');
        wxGetApp().ReportError(m);
        return;
    }

    // We want to receive the wxProcessEvent when cavern exits.
    cavern_out->SetNextHandler(this);

#ifdef CAVERNLOG_USE_THREADS
    thread = new CavernThread(this, cavern_out->GetInputStream());
    if (thread->Run() != wxTHREAD_NO_ERROR) {
        wxGetApp().ReportError(wxT("Thread failed to start"));
        delete thread;
        thread = NULL;
    }
#endif
}

void
CavernLogWindow::OnCavernOutput(wxCommandEvent & e_)
{
    CavernOutputEvent & e = (CavernOutputEvent&)e_;

    if (e.len > 0) {
        ssize_t n = e.len;
        if (size_t(n) > sizeof(buf) - (end - buf)) abort();
        memcpy(end, e.buf, n);
        log_txt.append((const char *)end, n);
        end += n;

        const unsigned char * p = buf;

        while (p != end) {
            int ch = *p;
            if (ch >= 0x80) {
                // Decode multi-byte UTF-8 sequence.
                if (ch < 0xc0) {
                    // Invalid UTF-8 sequence.
                    goto bad_utf8;
                } else if (ch < 0xe0) {
                    /* 2 byte sequence */
                    if (end - p < 2) {
                        // Incomplete UTF-8 sequence - try to read more.
                        break;
                    }
                    int ch1 = *++p;
                    if ((ch1 & 0xc0) != 0x80) {
                        // Invalid UTF-8 sequence.
                        goto bad_utf8;
                    }
                    ch = ((ch & 0x1f) << 6) | (ch1 & 0x3f);
                } else if (ch < 0xf0) {
                    /* 3 byte sequence */
                    if (end - p < 3) {
                        // Incomplete UTF-8 sequence - try to read more.
                        break;
                    }
                    int ch1 = *++p;
                    ch = ((ch & 0x1f) << 12) | ((ch1 & 0x3f) << 6);
                    if ((ch1 & 0xc0) != 0x80) {
                        // Invalid UTF-8 sequence.
                        goto bad_utf8;
                    }
                    int ch2 = *++p;
                    if ((ch2 & 0xc0) != 0x80) {
                        // Invalid UTF-8 sequence.
                        goto bad_utf8;
                    }
                    ch |= (ch2 & 0x3f);
                } else {
                    // Overlong UTF-8 sequence.
                    goto bad_utf8;
                }
            }
            ++p;

            if (false) {
bad_utf8:
                // Resync to next byte which starts a UTF-8 sequence.
                while (p != end) {
                    if (*p < 0x80 || (*p >= 0xc0 && *p < 0xf0)) break;
                    ++p;
                }
                cur += badutf8_html;
                continue;
            }

            switch (ch) {
                case '\r':
                    // Ignore.
                    break;
                case '\n': {
                    if (cur.empty()) continue;
                    if (cur[0] == ' ') {
                        if (source_line.empty()) {
                            // Source line shown for context.  Store it so we
                            // can use the caret line to highlight it.
                            swap(source_line, cur);
                        } else {
                            size_t caret = cur.rfind('^');
                            if (caret != wxString::npos) {
                                size_t tilde = cur.rfind('~');
                                if (tilde == wxString::npos || tilde < caret) {
                                    tilde = caret;
                                }
                                cur = "&nbsp;";
                                // FIXME: Need to count each & entity as one character...
                                cur.append(source_line, 1, caret - 1);
                                if (caret < source_line.size()) {
                                    cur.append("<b>");
                                    cur.append(highlight ? highlight : wxT("<span \"color:blue\">"));
                                    cur.append(source_line, caret, tilde + 1 - caret);
                                    cur.append("</span></b>");
                                }
                                if (tilde + 1 < source_line.size()) {
                                    cur.append(source_line, tilde + 1, wxString::npos);
                                }
                            } else {
                                // No caret in second line - just output both.
                                source_line.replace(0, 1, "&nbsp;");
                                source_line += "<br>\n&nbsp;";
                                source_line.append(cur, 1, wxString::npos);
                                swap(cur, source_line);
                            }
                            cur += "<br>\n";
                            AppendToPage(cur);
                            cur.clear();
                            source_line.clear();
                        }
                        continue;
                    }

                    if (!source_line.empty()) {
                        // Previous line was a source line without column info
                        // so just show it.
                        source_line.replace(0, 1, "&nbsp;");
                        source_line += "<br>\n";
                        AppendToPage(source_line);
                        source_line.clear();
                    }
#ifndef __WXMSW__
                    size_t colon = cur.find(':');
#else
                    // If the path is "C:\path\to\file.svx" then don't split at the
                    // : after the drive letter!  FIXME: better to look for ": "?
                    size_t colon = cur.find(':', 2);
#endif
                    if (colon != wxString::npos && colon < cur.size() - 2) {
                        ++colon;
                        size_t i = colon;
                        while (i < cur.size() - 2 &&
                               cur[i] >= wxT('0') && cur[i] <= wxT('9')) {
                            ++i;
                        }
                        if (i > colon && cur[i] == wxT(':') ) {
                            colon = i;
                            // Check for column number.
                            while (++i < cur.size() - 2 &&
                               cur[i] >= wxT('0') && cur[i] <= wxT('9')) { }
                            bool have_column = (i > colon + 1 && cur[i] == wxT(':'));
                            if (have_column) {
                                colon = i;
                            } else {
                                // If there's no colon, include a trailing ':'
                                // so that we can unambiguously split the href
                                // value up into filename, line and column.
                                ++colon;
                            }
                            wxString tag = wxT("<a href=\"");
                            tag.append(cur, 0, colon);
                            while (cur[++i] == wxT(' ')) { }
                            tag += wxT("\" target=\"");
                            wxString target(cur, i, wxString::npos);
                            target.Replace(badutf8_html, badutf8);
                            tag += target;
                            tag += wxT("\">");
                            cur.insert(0, tag);
                            size_t offset = colon + tag.size();
                            cur.insert(offset, wxT("</a>"));
                            offset += 4 + 2;

                            if (!have_column) --offset;

                            static const wxString & error_marker = wmsg(/*error*/93) + ":";
                            static const wxString & warning_marker = wmsg(/*warning*/4) + ":";
                            static const wxString & info_marker = wmsg(/*info*/485) + ":";

                            if (cur.substr(offset, error_marker.size()) == error_marker) {
                                // Show "error" marker in red.
                                highlight = wxT("<span style=\"color:red\">");
                                cur.insert(offset, highlight);
                                offset += 24 + error_marker.size() - 1;
                                cur.insert(offset, wxT("</span>"));
                            } else if (cur.substr(offset, warning_marker.size()) == warning_marker) {
                                // Show "warning" marker in orange.
                                highlight = wxT("<span style=\"color:orange\">");
                                cur.insert(offset, highlight);
                                offset += 27 + warning_marker.size() - 1;
                                cur.insert(offset, wxT("</span>"));
                            } else if (cur.substr(offset, info_marker.size()) == info_marker) {
                                // Show "info" marker in blue.
                                ++info_count;
                                highlight = wxT("<span style=\"color:blue\">");
                                cur.insert(offset, highlight);
                                offset += 25 + info_marker.size() - 1;
                                cur.insert(offset, wxT("</span>"));
                            } else {
                                highlight = NULL;
                            }

                            ++link_count;
                        }
                    }

                    // Save the scrollbar positions.
                    int scroll_x = 0, scroll_y = 0;
                    GetViewStart(&scroll_x, &scroll_y);

                    cur += wxT("<br>\n");
                    AppendToPage(cur);

                    if (!link_count) {
                        // Auto-scroll the window until we've reported a
                        // warning or error.
                        int x, y;
                        GetVirtualSize(&x, &y);
                        int xs, ys;
                        GetClientSize(&xs, &ys);
                        y -= ys;
                        int xu, yu;
                        GetScrollPixelsPerUnit(&xu, &yu);
                        Scroll(scroll_x, y / yu);
                    } else {
                        // Restore the scrollbar positions.
                        Scroll(scroll_x, scroll_y);
                    }

                    cur.clear();
                    break;
                }
                case '<':
                    cur += wxT("&lt;");
                    break;
                case '>':
                    cur += wxT("&gt;");
                    break;
                case '&':
                    cur += wxT("&amp;");
                    break;
                case '"':
                    cur += wxT("&#34;");
                    continue;
                default:
#ifdef wxUSE_UNICODE
                    cur += wxChar(ch);
#else
                    // This approach means that highlighting of "error" or
                    // "warning" won't work in translations where they contain
                    // non-ASCII characters, but wxWidgets >= 3.0 in always
                    // Unicode, so this corner case is already very uncommon,
                    // and will become irrelevant with time.
                    if (ch >= 128) {
                        cur += wxString::Format(wxT("&#%u;"), ch);
                    } else {
                        cur += (char)ch;
                    }
#endif
            }
        }

        size_t left = end - p;
        end = buf + left;
        if (left) memmove(buf, p, left);
        Update();
        return;
    }

    if (!source_line.empty()) {
        // Previous line was a source line without column info
        // so just show it.
        source_line.replace(0, 1, "&nbsp;");
        source_line += "<br>\n";
        AppendToPage(source_line);
        source_line.clear();
    }

    if (e.len <= 0 && buf != end) {
        // Truncated UTF-8 sequence.
        cur += badutf8_html;
    }
    if (!cur.empty()) {
        cur += "<br>\n";
        AppendToPage("<hr>" + cur);
    }

    /* TRANSLATORS: Label for button in aven’s cavern log window which
     * allows the user to save the log to a file. */
    AppendToPage(wxString::Format(wxT("<avenbutton id=%d name=\"%s\">"),
                                  (int)LOG_SAVE,
                                  wmsg(/*&Save Log*/446).c_str()));
    wxEndBusyCursor();
    delete cavern_out;
    cavern_out = NULL;
    if (e.len < 0) {
        /* Negative length indicates non-zero exit status from cavern. */
        /* TRANSLATORS: Label for button in aven’s cavern log window which
         * causes the survey data to be reprocessed. */
        AppendToPage(wxString::Format(wxT("<avenbutton default id=%d name=\"%s\">"),
                                      (int)LOG_REPROCESS,
                                      wmsg(/*&Reprocess*/184).c_str()));
        return;
    }
    AppendToPage(wxString::Format(wxT("<avenbutton id=%d name=\"%s\">"),
                                  (int)LOG_REPROCESS,
                                  wmsg(/*&Reprocess*/184).c_str()));
    AppendToPage(wxString::Format(wxT("<avenbutton default id=%d>"), (int)wxID_OK));
    Update();
    init_done = false;

    {
        wxString file3d(filename, 0, filename.length() - 3);
        file3d.append(wxT("3d"));
        if (!mainfrm->LoadData(file3d, survey)) {
            return;
        }
    }

    // Don't stay on log if there there are only "info" diagnostics.
    if (link_count == info_count) {
        wxCommandEvent dummy;
        OnOK(dummy);
    }
}

void
CavernLogWindow::OnEndProcess(wxProcessEvent & evt)
{
    CavernOutputEvent * e = new CavernOutputEvent();
    // Zero length indicates successful exit, negative length unsuccessful exit.
    e->len = (evt.GetExitCode() == 0 ? 0 : -1);
    QueueEvent(e);
}

void
CavernLogWindow::OnReprocess(wxCommandEvent &)
{
    process(filename);
}

void
CavernLogWindow::OnSave(wxCommandEvent &)
{
    wxString filelog(filename, 0, filename.length() - 3);
    filelog += wxT("log");
#ifdef __WXMOTIF__
    wxString ext(wxT("*.log"));
#else
    /* TRANSLATORS: Log files from running cavern (extension .log) */
    wxString ext = wmsg(/*Log files*/447);
    ext += wxT("|*.log");
#endif
    wxFileDialog dlg(this, wmsg(/*Select an output filename*/319),
                     wxString(), filelog, ext,
                     wxFD_SAVE|wxFD_OVERWRITE_PROMPT);
    if (dlg.ShowModal() != wxID_OK) return;
    filelog = dlg.GetPath();
    FILE * fh_log = wxFopen(filelog, wxT("w"));
    if (!fh_log) {
        wxGetApp().ReportError(wxString::Format(wmsg(/*Error writing to file “%s”*/110), filelog.c_str()));
        return;
    }
    fwrite(log_txt.data(), log_txt.size(), 1, fh_log);
    fclose(fh_log);
}

void
CavernLogWindow::OnOK(wxCommandEvent &)
{
    if (init_done) {
        mainfrm->HideLog(this);
    } else {
        mainfrm->InitialiseAfterLoad(filename, survey);
        init_done = true;
    }
}