Extension:AbcMusic

require_once("$IP/extensions/AbcMusic.php");

<?php
 
/**
 * AbcMusic.php  -- MediaWiki Extension
 *
 * @author David A. Tanzer
 * @link http://www.mediawiki.org/wiki/Extension:AbcMusic
 */
 
$wgLilypond = "/usr/bin/lilypond";
$wgAbc2ly = "/usr/bin/abc2ly"; 
 
$wgExtensionCredits['parserhook'][] = array(
        'name' => 'AbcMusic',
        'version' => '1.0',
        'author' => 'David A. Tanzer',
        'url' => 'http://www.mediawiki.org/wiki/Extension:AbcMusic',
        'description' => 'Rendering of music from the ABC text notation.',
);
 
$wgExtensionFunctions[] = 'wfAbcMusicExtension';
 
function wfAbcMusicExtension() {
  global $wgParser;
  $wgParser->setHook( 'abc', 'renderAbc' );
  $wgParser->setHook( 'abclink', 'renderAbcLink' );
}
 
function renderAbcLink( $abcLinkText ) {
 
  return renderAbc(file_get_contents(trim($abcLinkText)));
}
 
function renderAbc( $abcText ) {
 
  $result = "";
 
  $songs = splitSongs( $abcText );
 
  foreach ($songs as $song) {
    $result = $result . renderSong( $song );
  }
 
  return $result;
}
 
// split the text into a list of substrings, one for each song within
// the file.  Every song in an ABC file begins with an X: line.
//
function splitSongs( $abcText ) {
  $songs = array();
 
  $lines = explode( "\n", $abcText );
 
  $firstSong = 1;
 
  foreach ($lines as $line) {
    $line = trim( $line );
 
    if ($line[0] == "X" && $line[1] == ":") {
      // first line of a new song
 
      if ( $firstSong != 1 ) {
         // append the previous song to the result array
         $songs[] = implode( "\n", $currSong );
      } 
      $firstSong = 0;  
 
      $currSong = array();
    }
 
    $currSong[] = $line;
  }
 
  $songs[] = implode( "\n", $currSong );
 
  return $songs;
}
 
function renderSong( $abcText ) {
  global $wgMathPath, $wgMathDirectory, $wgTmpDirectory, $wgLilypond, $wgAbc2ly;
 
  $mf   = wfMsg( "math_failure" );
 
  // filename is based upon a large hash of the entire file contents
  //
  $hash = md5( $abcText );
 
  $link = "<img src=\"" . $wgMathPath . "/" . $hash.".png\" alt=\""
    .htmlspecialchars( $abcText )."\">";
 
  // if the output file already exists, just return the html
  // that points to it.
  //
  if( file_exists( "$wgMathDirectory/$hash.png" ) ) {
    return $link;
  }
 
  $dirMsg = ensureDirectories();
  if ($dirMsg != "") {
    return $dirMsg;
  } 
 
  // write the string to a temporary .abc file
  //
  $abcFile = $hash . ".abc";
  $abcOut = fopen( $wgTmpDirectory . "/" . $abcFile, "w");
  fwrite( $abcOut, $abcText );
  fclose( $abcOut );
 
  $lyFile = $hash . ".ly";
  $lyFile2 = "sed_" . $lyFile;
 
  wfDebug( "Lilypond: $cmd" );
 
  $cmdAbc = $wgAbc2ly . " " . escapeshellarg($abcFile) . " 2>&1";
 
// some dirty-work: use sed to remove the tagline from the generated .ly file
// the current version of abc2ly lacks a command-line argument to modify, or suppress, the tagline
//
  $sedArgFname = $wgTmpDirectory . "/sedargfile"; 
  $sedArgOut = fopen( $sedArgFname, "w" );
  fwrite( $sedArgOut, "s/tagline = .*/tagline = \"\"/" ); 
  fclose( $sedArgOut );
  $cmdSed = "sed -f " . $sedArgFname . " < ". $lyFile . " > " . $lyFile2; 
 
  $cmdLily = $wgLilypond .
    " --safe --backend=eps --format=png --header=texidoc " .
    escapeshellarg($lyFile2) . " 2>&1";
 
  $oldcwd = getcwd();
 
  chdir( $wgTmpDirectory );
 
  exec( $cmdAbc, $output, $ret );    // abc -> ly
  exec( $cmdSed, $output, $ret );    // remove tagline from .ly
  exec( $cmdLily, $output, $ret );   // ly -> png
 
  chdir( $oldcwd );
 
  if( $ret != 0 ) {
     return "<br><b>LilyPond error:</b><br><i>"
    . str_replace( array( $hash, " " ),
      array( "<b>your code</b>", "&nbsp;" ),
      nl2br( htmlentities( join( "\n", $output ) ) ) )
    . "</i><br>";
  }
 
  $outputFile = $wgTmpDirectory."/sed_".$hash.".png";
 
  if( !file_exists( $outputFile ) ) {
    return "<b>$mf (" . wfMsg( "math_image_error" ) . ")</b>";
  }
 
  rename( $outputFile, $wgMathDirectory."/".$hash.".png" );
 
  unlink( $sedArgFname );
  removeTempFiles($hash);
 
  if( !file_exists( $wgMathDirectory."/".$hash.".png" ) ) {
    $errmsg = wfMsg( "math_image_error" );
    return "<h3>$mf ($errmsg): " .
      htmlspecialchars($abcText) . "</h3>";
  }
 
  return $link;
}
 
function ensureDirectories() {
 
  global $wgMathDirectory, $wgTmpDirectory;
 
  if( !file_exists( $wgMathDirectory ) ) {
    if( !@mkdir( $wgMathDirectory ) ) {
      return "<b>$mf (" . wfMsg( "math_bad_output" ) .
        $wgMathDirectory . ")</b>";
    }
  } elseif( !is_dir( $wgMathDirectory ) ||
      !is_writable( $wgMathDirectory ) ) {
    return "<b>$mf (" . wfMsg( "math_bad_output" ) . ")</b>";
  }
  if( !file_exists( $wgTmpDirectory ) ) {
    if( !@mkdir( $wgTmpDirectory ) ) {
      return "<b>$mf (" . wfMsg( "math_bad_tmpdir" )
        . ")</b>";
    }
  } elseif( !is_dir( $wgTmpDirectory ) ||
      !is_writable( $wgTmpDirectory ) ) {
    return "<b>$mf (" . wfMsg( "math_bad_tmpdir" ) . ")</b>";
  }
 
  return "";
} 
 
function removeTempFiles($hash) {
 
  global $wgTmpDirectory, $wgMathDirectory;
 
  $files = opendir( $wgTmpDirectory );
  $last_page = 0;
 
  while( false !== ($file = readdir( $files ))) {
 
    if( substr( $file, 4, 32 ) != $hash &&
        substr( $file, 0, 32 ) != $hash ) {
      continue;
    }
 
    $file_absolute = $wgTmpDirectory . "/" . $file;
 
    if( !is_file( $file_absolute ) )
      continue;
 
    unlink( $file_absolute );
  }
  closedir( $files );
}
?>