Parse comments without recursion to avoid RangeError.

Fixes #993
mishoo · Apr 16, 2016 · e4fa4b1 · e4fa4b1
1 parent 4b4528e
commit e4fa4b1
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Showing 2 changed files with 57 additions and 29 deletions.
diff --git a/lib/parse.js b/lib/parse.js
@@ -421,7 +421,7 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
         S.col = S.tokcol + (S.pos - S.tokpos);
         S.comments_before.push(token(type, ret, true));
         S.regex_allowed = regex_allowed;
-        return next_token();
+        return next_token;
     };
 
     var skip_multiline_comment = with_eof_error("Unterminated multiline comment", function(){
@@ -439,7 +439,7 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
         S.comments_before.push(token("comment2", text, true));
         S.regex_allowed = regex_allowed;
         S.newline_before = nlb;
-        return next_token();
+        return next_token;
     });
 
     function read_name() {
@@ -548,36 +548,45 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
     function next_token(force_regexp) {
         if (force_regexp != null)
             return read_regexp(force_regexp);
-        skip_whitespace();
-        start_token();
-        if (html5_comments) {
-            if (looking_at("<!--")) {
-                forward(4);
-                return skip_line_comment("comment3");
+        for (;;) {
+            skip_whitespace();
+            start_token();
+            if (html5_comments) {
+                if (looking_at("<!--")) {
+                    forward(4);
+                    skip_line_comment("comment3");
+                    continue;
+                }
+                if (looking_at("-->") && S.newline_before) {
+                    forward(3);
+                    skip_line_comment("comment4");
+                    continue;
+                }
             }
-            if (looking_at("-->") && S.newline_before) {
-                forward(3);
-                return skip_line_comment("comment4");
+            var ch = peek();
+            if (!ch) return token("eof");
+            var code = ch.charCodeAt(0);
+            switch (code) {
+              case 34: case 39: return read_string(ch);
+              case 46: return handle_dot();
+              case 47: {
+                  var tok = handle_slash();
+                  if (tok === next_token) continue;
+                  return tok;
+              }
             }
-        }
-        var ch = peek();
-        if (!ch) return token("eof");
-        var code = ch.charCodeAt(0);
-        switch (code) {
-          case 34: case 39: return read_string(ch);
-          case 46: return handle_dot();
-          case 47: return handle_slash();
-        }
-        if (is_digit(code)) return read_num();
-        if (PUNC_CHARS(ch)) return token("punc", next());
-        if (OPERATOR_CHARS(ch)) return read_operator();
-        if (code == 92 || is_identifier_start(code)) return read_word();
-
-        if (shebang) {
-            if (S.pos == 0 && looking_at("#!")) {
-                forward(2);
-                return skip_line_comment("comment5");
+            if (is_digit(code)) return read_num();
+            if (PUNC_CHARS(ch)) return token("punc", next());
+            if (OPERATOR_CHARS(ch)) return read_operator();
+            if (code == 92 || is_identifier_start(code)) return read_word();
+            if (shebang) {
+                if (S.pos == 0 && looking_at("#!")) {
+                    forward(2);
+                    skip_line_comment("comment5");
+                    continue;
+                }
             }
+            break;
         }
         parse_error("Unexpected character '" + ch + "'");
     };

diff --git a/test/mocha/huge-number-of-comments.js b/test/mocha/huge-number-of-comments.js
@@ -0,0 +1,19 @@
+var Uglify = require('../../');
+var assert = require("assert");
+
+describe("Huge number of comments.", function() {
+    it("Should parse and compress code with thousands of consecutive comments", function() {
+        var js = 'function lots_of_comments(x) { return 7 -';
+        var i;
+        for (i = 1; i <= 5000; ++i) { js += "// " + i + "\n"; }
+        for (; i <= 10000; ++i) { js += "/* " + i + " */ /**/"; }
+        js += "x; }";
+        var result = Uglify.minify(js, {
+            fromString: true,
+            mangle: false,
+            compress: {}
+        });
+        assert.strictEqual(result.code, "function lots_of_comments(x){return 7-x}");
+    });
+});
+