JSMin.php : Overhaul for readability, more useful exceptions

min/lib/JSMin.php

@@ -11,11 +11,6 @@
  * comments that begin with "/*!" (for documentation purposes). In the latter case
  * newlines are inserted around the comment to enhance readability.
  *
- * Known issue: regular expressions containing quote characters must be proceeded
- * by one of the following characters: (,=:[!&|?
- * E.g. JSMin will fail on the following: return /'/;
- * The simple workaround is to wrap the expression in parenthesis: return (/'/); 
- * 
  * PHP 5 or higher is required.
  *
  * Permission is hereby granted to use this version of the library under the
@@ -59,7 +54,7 @@ class JSMin {
     const ORD_LF    = 10;
     const ORD_SPACE = 32;
     
-    protected $a           = '';
+    protected $a           = "\n";
     protected $b           = '';
     protected $input       = '';
     protected $inputIndex  = 0;
@@ -79,12 +74,61 @@ class JSMin {
         return $jsmin->min();
     }
     
-    protected function __construct($input)
+    /**
+     * Setup process
+     */
+    public function __construct($input)
     {
         $this->input       = str_replace("\r\n", "\n", $input);
         $this->inputLength = strlen($this->input);
     }
     
+    /**
+     * Perform minification, return result
+     */
+    public function min()
+    {
+        if ($this->output !== '') {
+            // min already run
+            return $this->output;
+        }
+        $this->action(3);
+        
+        while ($this->a !== null) {
+            // determine next action
+            if ($this->a === ' ') {
+                $act = $this->isAlphaNum($this->b) ? 1 : 2;
+            } elseif ($this->a === "\n") {
+                if ($this->b === ' ') {
+                    $act = 3;
+                } elseif (false !== strpos('{[(+-', $this->b)) {
+                    $act = 1;
+                } else {
+                    $act = $this->isAlphaNum($this->b) ? 1 : 2;
+                }
+            } else {
+                if ($this->b === ' ') {
+                    $act = $this->isAlphaNum($this->a) ? 1 : 3;
+                } elseif ($this->b === "\n") {
+                    if (false !== strpos('}])+-"\'', $this->a)) {
+                        $act = 1;
+                    } else {
+                        $act = $this->isAlphaNum($this->a) ? 1 : 3;
+                    }
+                } else {
+                    $act = 1;
+                }
+            }
+            $this->action($act);
+        }
+        return $this->output;
+    }
+    
+    /**
+     * 1 = Output A. Copy B to A. Get the next B.
+     * 2 = Copy B to A. Get the next B. (Delete A).
+     * 3 = Get the next B. (Delete B).
+     */
     protected function action($d)
     {
         switch ($d) {
@@ -94,65 +138,82 @@ class JSMin {
             case 2:
                 $this->a = $this->b;
                 if ($this->a === "'" || $this->a === '"') {
-                    for (;;) {
+                    // string literal
+                    $str = ''; // in case needed for exception
+                    while (true) {
                         $this->output .= $this->a;
                         $this->a       = $this->get();
                         if ($this->a === $this->b) {
+                            // end quote
                             break;
                         }
                         if (ord($this->a) <= self::ORD_LF) {
-                            throw new JSMinException('Unterminated string literal.');
+                            throw new JSMin_UnterminatedStringException('Contents: ' . $str);
                         }
+                        $str .= $this->a;
                         if ($this->a === '\\') {
                             $this->output .= $this->a;
                             $this->a       = $this->get();
+                            $str .= $this->a;
                         }
                     }
                 }
                 // fallthrough
             case 3:
                 $this->b = $this->next();
-                if ($this->b === '/') {
+                if ($this->b === '/' && $this->isRegexpLiteral()) {
-                    switch ($this->a) {
+                    // RegExp literal
-                        case "\n": 
-                        case ' ':
-                            if (! $this->spaceBeforeRegExp($this->output)) {
-                                break;
-                            }
-                        case '{':
-                        case ';':
-                        case '(':
-                        case ',':
-                        case '=':
-                        case ':':
-                        case '[':
-                        case '!':
-                        case '&':
-                        case '|':
-                        case '?':
                     $this->output .= $this->a . $this->b;
-                            for (;;) {
+                    $pattern = '/'; // in case needed for exception
+                    while (true) {
                         $this->a = $this->get();
+                        $pattern .= $this->a;
                         if ($this->a === '/') {
-                                    break; // for (;;)
+                            // end pattern
+                            break; // while (true)
                         } elseif ($this->a === '\\') {
                             $this->output .= $this->a;
                             $this->a       = $this->get();
+                            $pattern      .= $this->a;
                         } elseif (ord($this->a) <= self::ORD_LF) {
-                                    throw new JSMinException('Unterminated regular expression literal.');
+                            throw new JSMin_UnterminatedRegExpException('Contents: '. $pattern);
                         }
                         $this->output .= $this->a;
                     }
                     $this->b = $this->next();
-                            break; // switch ($this->a)
-                        // end case ?
-                    }
                 }
                 break; // switch ($d)
             // end case 3
         }
     }
     
+    protected function isRegexpLiteral()
+    {
+        if (false !== strpos("\n{;(,=:[!&|?", $this->a)) {
+            return true;
+        }
+        if (' ' === $this->a) {
+            // see if preceeded by keyword
+            $length = strlen($this->output);
+            if ($length < 2) {
+                return true;
+            }
+            if (preg_match('/(?:case|else|in|return|typeof)$/', $this->output, $m)) {
+                if ($this->output === $m[0]) {
+                    return true;
+                }
+                $charBeforeKeyword = substr($this->output, $length - strlen($m[0]) - 1, 1);
+                if (! $this->isAlphaNum($charBeforeKeyword)) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+    
+    /**
+     * Get next char. Convert ctrl char to space.
+     */
     protected function get()
     {
         $c = $this->lookAhead;
@@ -162,170 +223,98 @@ class JSMin {
                 $c = $this->input[$this->inputIndex];
                 $this->inputIndex += 1;
             } else {
-                $c = null;
+                return null;
             }
         }
-        return ($c === "\r") 
+        if ($c === "\r" || $c === "\n") {
-            ? "\n"
+            return "\n";
-            : ($c === null || $c === "\n" || ord($c) >= self::ORD_SPACE
+        }
-                ? $c
+        if (ord($c) < self::ORD_SPACE) {
-                : ' ');
+            // control char
-    }
+            return ' ';
-
+        }
-    protected function isAlphaNum($c)
+        return $c;
-    {
-        return (ord($c) > 126 
-                || $c === '\\' 
-                || preg_match('/^[\w\$]$/', $c) === 1);
-    }
-
-    protected function min()
-    {
-        $this->a = "\n";
-        $this->action(3);
-
-        while ($this->a !== null) {
-            switch ($this->a) {
-                case ' ':
-                    if ($this->isAlphaNum($this->b)) {
-                        $this->action(1);
-                    } else {
-                        $this->action(2);
-                    }
-                    break;
-                case "\n":
-                    switch ($this->b) {
-                        case '{':
-                        case '[':
-                        case '(':
-                        case '+':
-                        case '-':
-                            $this->action(1);
-                            break;
-                        case ' ':
-                            $this->action(3);
-                            break;
-                        default:
-                            if ($this->isAlphaNum($this->b)) {
-                                $this->action(1);
-                            } else {
-                                $this->action(2);
-                            }
-                    }
-                    break;
-                default:
-                    switch ($this->b) {
-                        case ' ':
-                            if ($this->isAlphaNum($this->a)) {
-                                $this->action(1);
-                                break; // switch ($this->b)
-                            }
-                            $this->action(3);
-                            break; // switch ($this->b)
-                        case "\n":
-                            switch ($this->a) {
-                                case '}':
-                                case ']':
-                                case ')':
-                                case '+':
-                                case '-':
-                                case '"':
-                                case "'":
-                                    $this->action(1);
-                                    break; // switch ($this->a)
-                                default:
-                                    if ($this->isAlphaNum($this->a)) {
-                                        $this->action(1);
-                                    } else {
-                                        $this->action(3);
-                                    }
-                            }
-                            break; // switch ($this->b)
-                        default:
-                            $this->action(1);
-                            break; // switch ($this->b)
-                    }
-                // end default
-            }
-        }
-        return $this->output;
-    }
-
-    protected function next()
-    {
-        $get = $this->get();
-        if ($get === '/') {
-            $commentContents = '';
-            switch ($this->peek()) {
-                case '/':
-                    // "//" comment
-                    for (;;) {
-                        $get = $this->get();
-                        $commentContents .= $get;
-                        if (ord($get) <= self::ORD_LF) {
-                            return preg_match('/^\\/@(?:cc_on|if|elif|else|end)\\b/', $commentContents)
-                                ? "/{$commentContents}"
-                                : $get;
-                        }
-                    }
-                case '*':
-                    // "/* */" comment
-                    $this->get();
-                    for (;;) {
-                        $get = $this->get();
-                        switch ($get) {
-                            case '*':
-                                if ($this->peek() === '/') {
-                                    $this->get();
-                                    if (0 === strpos($commentContents, '!')) {
-                                        // YUI Compressor style
-                                        return "\n/*" . substr($commentContents, 1) . "*/\n";
-                                    }
-                                    return preg_match('/^@(?:cc_on|if|elif|else|end)\\b/', $commentContents)
-                                        ? "/*{$commentContents}*/" // IE conditional compilation
-                                        : ' ';
-                                }
-                                break;
-                            case null:
-                                throw new JSMinException('Unterminated comment.');
-                        }
-                        $commentContents .= $get;
-                    }
-                default:
-                    return $get;
-            }
-        }
-        return $get;
     }
     
+    /**
+     * Get next char. If is ctrl character, translate to a space or newline.
+     */
     protected function peek()
     {
         $this->lookAhead = $this->get();
         return $this->lookAhead;
     }
     
-    protected function spaceBeforeRegExp($output)
+    /**
+     * Is $c a letter, digit, underscore, dollar sign, escape, or non-ASCII?
+     */
+    protected function isAlphaNum($c)
     {
-        $length = strlen($output);
+        return (preg_match('/^[0-9a-zA-Z_\\$\\\\]$/', $c) || ord($c) > 126);
-        $isSpace = false;
-        $tmp = "";
-        foreach (array("case", "else", "in", "return", "typeof") as $word) {
-            if ($length === strlen($word)) {
-                $isSpace = ($word === $output);
-            } elseif ($length > strlen($word)) {
-                $tmp = substr($output, $length - strlen($word) - 1);
-                $isSpace = (substr($tmp, 1) === $word) && ! $this->isAlphaNum($tmp[0]);
     }
-            if ($isSpace) {
+    
-                break;
+    protected function singleLineComment()
+    {
+        $comment = '';
+        while (true) {
+            $get = $this->get();
+            $comment .= $get;
+            if (ord($get) <= self::ORD_LF) {
+                // EOL reached
+                if (preg_match('/^\\/@(?:cc_on|if|elif|else|end)\\b/', $comment)) {
+                    // conditional comment, preserve it
+                    return "/{$comment}";
                 }
+                return $get;
             }
-        return ($length < 2) 
-            ? true 
-            : $isSpace;
         }
     }
     
-class JSMinException extends Exception {
+    protected function multipleLineComment()
-
+    {
+        $this->get();
+        $comment = '';
+        while (true) {
+            $get = $this->get();
+            if ($get === '*') {
+                if ($this->peek() === '/') {
+                    // end of comment reached
+                    $this->get();
+                    if (0 === strpos($comment, '!')) {
+                        // is YUI Compressor style, keep it
+                        return "\n/*" . substr($comment, 1) . "*/\n";
                     }
+                    if (preg_match('/^@(?:cc_on|if|elif|else|end)\\b/', $comment)) {
+                        // is IE conditional, keep it
+                        return "/*{$comment}*/";
+                    }
+                    return ' ';
+                }
+            } elseif ($get === null) {
+                throw new JSMin_UnterminatedCommentException('Contents: ' . $comment);
+            }
+            $comment .= $get;
+        }
+    }
+    
+    /**
+     * Get the next character, skipping over comments.
+     * Some comments may be preserved.
+     */
+    protected function next()
+    {
+        $get = $this->get();
+        if ($get !== '/') {
+            return $get;
+        }
+        switch ($this->peek()) {
+            case '/': return $this->singleLineComment();
+            case '*': return $this->multipleLineComment();
+            default: return $get;
+        }
+    }
+}
+
+class JSMin_UnterminatedStringException extends Exception {}
+class JSMin_UnterminatedCommentException extends Exception {}
+class JSMin_UnterminatedRegExpException extends Exception {}