gn: handle continued suffix comments

tools/gn/tokenizer.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "tools/gn/tokenizer.h"
 
 #include "base/logging.h"
 #include "base/strings/string_util.h"
 #include "tools/gn/input_file.h"
 
@@ skipping 110 matching lines @@
         type = Token::FALSE_TOKEN;
     } else if (type == Token::UNCLASSIFIED_COMMENT) {
       // Find back to the previous \n, and trim. If it's only whitespace, then
       // this is on a line alone, otherwise it's a suffix comment.
       size_t newline_location = input_.find_last_of('\n', token_begin);
       base::StringPiece to_newline = input_.substr(
           newline_location + 1, token_begin - (newline_location + 1));
       std::string trimmed;
       // TODO(scottmg): Should write TrimWhitespace for StringPiece.
       base::TrimWhitespace(to_newline.as_string(), base::TRIM_ALL, &trimmed);
-      if (trimmed.empty())
+      if (trimmed.empty() &&
+          // If it's a standalone comment, but is a continuation of a comment
+          // on a previous line, then instead make it a continued suffix
+          // comment.
+          (tokens_.empty() || tokens_.back().type() != Token::SUFFIX_COMMENT ||
+           tokens_.back().location().line_number() + 1 !=
+               location.line_number())) {
         type = Token::LINE_COMMENT;
-      else
+      } else {
         type = Token::SUFFIX_COMMENT;
+      }
     }
 
     tokens_.push_back(Token(location, type, token_value));
   }
   if (err_->has_error())
     tokens_.clear();
   return tokens_;
 }
 
 // static
@@ skipping 218 matching lines @@
   } else if (cur_char() == '/' && cur_ + 1 < input_.size() &&
       (input_[cur_ + 1] == '/' || input_[cur_ + 1] == '*')) {
     // Different types of comments.
     help = "Comments should start with # instead";
   } else {
     help = "I have no idea what this is.";
   }
 
   return Err(location, "Invalid token.", help);
 }