From ed676b2d9a6ec19004f5aa27bc7e461570788ed6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jaakko=20Kera=CC=88nen?= <jaakko.keranen@iki.fi>
Date: Tue, 18 Aug 2015 15:21:38 +0300
Subject: [PATCH] Scripting|Info|libcore: No exception when parsing an embedded
 script

ScriptLex can now be told to stop parsing statements when it encounters
a mismatched closing }. This occurs normally when a Doomsday Script
block is parsed inside an Info document, because the Info parser has
no way of knowing how long the embedded script is unless it actually
parses it using ScriptLex.

Previously ScriptLex just blindly tried to read statements until it
hit an exception.
---
 .../libcore/include/de/scriptsys/scriptlex.h  | 20 ++++++++++++---
 doomsday/sdk/libcore/src/data/info.cpp        | 25 ++++++-------------
 .../sdk/libcore/src/scriptsys/scriptlex.cpp   | 10 +++++++-
 3 files changed, 33 insertions(+), 22 deletions(-)

diff --git a/doomsday/sdk/libcore/include/de/scriptsys/scriptlex.h b/doomsday/sdk/libcore/include/de/scriptsys/scriptlex.h
index f1ad21e041..a39913c174 100644
--- a/doomsday/sdk/libcore/include/de/scriptsys/scriptlex.h
+++ b/doomsday/sdk/libcore/include/de/scriptsys/scriptlex.h
@@ -14,15 +14,17 @@
  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
  * General Public License for more details. You should have received a copy of
  * the GNU Lesser General Public License along with this program; if not, see:
- * http://www.gnu.org/licenses</small> 
+ * http://www.gnu.org/licenses</small>
  */
- 
+
 #ifndef LIBDENG2_SCRIPTLEX_H
 #define LIBDENG2_SCRIPTLEX_H
 
 #include "../Lex"
 #include "../TokenBuffer"
 
+#include <QFlags>
+
 namespace de {
 
 #ifdef WIN32
@@ -88,17 +90,25 @@ class DENG2_PUBLIC ScriptLex : public Lex
     static String const SCOPE_ASSIGN;
     static String const WEAK_ASSIGN;
 
+    enum Behavior
+    {
+        DefaultBehavior = 0,
+        StopAtMismatchedCloseBrace = 0x1 ///< Mismatched } is treated as end of input.
+    };
+    Q_DECLARE_FLAGS(Behaviors, Behavior)
+
 public:
     ScriptLex(String const &input = "");
 
     /**
      * Analyze one complete statement from the input.
      *
-     * @param output Buffer for output tokens.
+     * @param output    Buffer for output tokens.
+     * @param behavior  Parsing behavior.
      *
      * @return  The number of tokens added to the output token buffer.
      */
-    duint getStatement(TokenBuffer &output);
+    duint getStatement(TokenBuffer &output, Behaviors const &behavior = DefaultBehavior);
 
     /**
      * Parse a string.
@@ -134,6 +144,8 @@ class DENG2_PUBLIC ScriptLex : public Lex
     static ddouble tokenToNumber(Token const &token);
 };
 
+Q_DECLARE_OPERATORS_FOR_FLAGS(ScriptLex::Behaviors)
+
 } // namespace de
 
 #endif /* LIBDENG2_SCRIPTLEX_H */
diff --git a/doomsday/sdk/libcore/src/data/info.cpp b/doomsday/sdk/libcore/src/data/info.cpp
index e32fb87173..68fd5e4670 100644
--- a/doomsday/sdk/libcore/src/data/info.cpp
+++ b/doomsday/sdk/libcore/src/data/info.cpp
@@ -350,29 +350,20 @@ DENG2_PIMPL(Info)
         return value;
     }
 
-    InfoValue parseScript(int numStatements = 0)
+    InfoValue parseScript(int requiredStatementCount = 0)
     {
         int startPos = cursor - 1;
         String remainder = content.substr(startPos);
         ScriptLex lex(remainder);
-        try
-        {
-            TokenBuffer tokens;
-            int count = 0;
 
-            // Read an appropriate number of statements.
-            while(lex.getStatement(tokens))
-            {
-                if(numStatements > 0 && ++count == numStatements)
-                    goto success;
-            }
-            throw SyntaxError("Info::parseScript",
-                              QString("Unexpected end of script starting at line %1").arg(currentLine));
-success:;
-        }
-        catch(ScriptLex::MismatchedBracketError const &)
+        TokenBuffer tokens;
+        int count = 0;
+
+        // Read an appropriate number of statements.
+        while(lex.getStatement(tokens, ScriptLex::StopAtMismatchedCloseBrace))
         {
-            // A mismatched bracket signals the end of the script block.
+            if(requiredStatementCount > 0 &&
+               ++count == requiredStatementCount) break; // We're good now.
         }
 
         // Continue parsing normally from here.
diff --git a/doomsday/sdk/libcore/src/scriptsys/scriptlex.cpp b/doomsday/sdk/libcore/src/scriptsys/scriptlex.cpp
index 9ff46a9a41..d8c1b20cec 100644
--- a/doomsday/sdk/libcore/src/scriptsys/scriptlex.cpp
+++ b/doomsday/sdk/libcore/src/scriptsys/scriptlex.cpp
@@ -60,7 +60,7 @@ String const ScriptLex::WEAK_ASSIGN("?=");
 ScriptLex::ScriptLex(String const &input) : Lex(input)
 {}
 
-duint ScriptLex::getStatement(TokenBuffer &output)
+duint ScriptLex::getStatement(TokenBuffer &output, Behaviors const &behavior)
 {
     // Get rid of the previous contents of the token buffer.
     output.clear();
@@ -90,6 +90,14 @@ duint ScriptLex::getStatement(TokenBuffer &output)
         // Tokens are primarily separated by whitespace.
         skipWhiteExceptNewline();
 
+        if(behavior.testFlag(StopAtMismatchedCloseBrace) &&
+           !bracketLevel[BRACKET_CURLY] &&
+            peek() == '}')
+        {
+            // Don't read past the bracket.
+            break;
+        }
+
         // This will be the first character of the token.
         QChar c = get();