Package org.antlr.runtime.debug

Class DebugEventSocketProxy

  • All Implemented Interfaces:
    DebugEventListener
    public class DebugEventSocketProxy
extends BlankDebugEventListener
    A proxy debug event listener that forwards events over a socket to a debugger (or any other listener) using a simple text-based protocol; one event per line. ANTLRWorks listens on server socket with a RemoteDebugEventSocketListener instance. These two objects must therefore be kept in sync. New events must be handled on both sides of socket.

    • Field Detail

      • port

        protected int port

      • socket

        protected Socket socket

      • grammarFileName

        protected String grammarFileName

      • adaptor

        protected TreeAdaptor adaptor
        Almost certainly the recognizer will have adaptor set, but we don't know how to cast it (Parser or TreeParser) to get the adaptor field. Must be set with a constructor. :(

    • Method Detail

      • commence

        public void commence()
        Description copied from interface: DebugEventListener
        Announce that parsing has begun. Not technically useful except for sending events over a socket. A GUI for example will launch a thread to connect and communicate with a remote parser. The thread will want to notify the GUI when a connection is made. ANTLR parsers trigger this upon entry to the first rule (the ruleLevel is used to figure this out).
        Specified by:
        commence in interface DebugEventListener
        Overrides:
        commence in class BlankDebugEventListener

      • terminate

        public void terminate()
        Description copied from interface: DebugEventListener
        Parsing is over; successfully or not. Mostly useful for telling remote debugging listeners that it's time to quit. When the rule invocation level goes to zero at the end of a rule, we are done parsing.
        Specified by:
        terminate in interface DebugEventListener
        Overrides:
        terminate in class BlankDebugEventListener

      • ack

        protected void ack()

      • transmit

        protected void transmit​(String event)

      • enterRule

        public void enterRule​(String grammarFileName,
                      String ruleName)
        Description copied from interface: DebugEventListener
        The parser has just entered a rule. No decision has been made about which alt is predicted. This is fired AFTER init actions have been executed. Attributes are defined and available etc... The grammarFileName allows composite grammars to jump around among multiple grammar files.
        Specified by:
        enterRule in interface DebugEventListener
        Overrides:
        enterRule in class BlankDebugEventListener

      • exitRule

        public void exitRule​(String grammarFileName,
                     String ruleName)
        Description copied from interface: DebugEventListener
        This is the last thing executed before leaving a rule. It is executed even if an exception is thrown. This is triggered after error reporting and recovery have occurred (unless the exception is not caught in this rule). This implies an "exitAlt" event. The grammarFileName allows composite grammars to jump around among multiple grammar files.
        Specified by:
        exitRule in interface DebugEventListener
        Overrides:
        exitRule in class BlankDebugEventListener

      • enterDecision

        public void enterDecision​(int decisionNumber,
                          boolean couldBacktrack)
        Description copied from interface: DebugEventListener
        Every decision, fixed k or arbitrary, has an enter/exit event so that a GUI can easily track what LT/consume events are associated with prediction. You will see a single enter/exit subrule but multiple enter/exit decision events, one for each loop iteration.
        Specified by:
        enterDecision in interface DebugEventListener
        Overrides:
        enterDecision in class BlankDebugEventListener

      • LT

        public void LT​(int i,
               Token t)
        Description copied from interface: DebugEventListener
        Somebody (anybody) looked ahead. Note that this actually gets triggered by both LA and LT calls. The debugger will want to know which Token object was examined. Like consumeToken, this indicates what token was seen at that depth. A remote debugger cannot look ahead into a file it doesn't have so LT events must pass the token even if the info is redundant.
        Specified by:
        LT in interface DebugEventListener
        Overrides:
        LT in class BlankDebugEventListener

      • rewind

        public void rewind​(int i)
        Description copied from interface: DebugEventListener
        After an arbitrairly long lookahead as with a cyclic DFA (or with any backtrack), this informs the debugger that stream should be rewound to the position associated with marker.
        Specified by:
        rewind in interface DebugEventListener
        Overrides:
        rewind in class BlankDebugEventListener

      • rewind

        public void rewind()
        Description copied from interface: DebugEventListener
        Rewind to the input position of the last marker. Used currently only after a cyclic DFA and just before starting a sem/syn predicate to get the input position back to the start of the decision. Do not "pop" the marker off the state. mark(i) and rewind(i) should balance still.
        Specified by:
        rewind in interface DebugEventListener
        Overrides:
        rewind in class BlankDebugEventListener

      • location

        public void location​(int line,
                     int pos)
        Description copied from interface: DebugEventListener
        To watch a parser move through the grammar, the parser needs to inform the debugger what line/charPos it is passing in the grammar. For now, this does not know how to switch from one grammar to the other and back for island grammars etc... This should also allow breakpoints because the debugger can stop the parser whenever it hits this line/pos.
        Specified by:
        location in interface DebugEventListener
        Overrides:
        location in class BlankDebugEventListener

      • recognitionException

        public void recognitionException​(RecognitionException e)
        Description copied from interface: DebugEventListener
        A recognition exception occurred such as NoViableAltException. I made this a generic event so that I can alter the exception hierachy later without having to alter all the debug objects. Upon error, the stack of enter rule/subrule must be properly unwound. If no viable alt occurs it is within an enter/exit decision, which also must be rewound. Even the rewind for each mark must be unwount. In the Java target this is pretty easy using try/finally, if a bit ugly in the generated code. The rewind is generated in DFA.predict() actually so no code needs to be generated for that. For languages w/o this "finally" feature (C++?), the target implementor will have to build an event stack or something. Across a socket for remote debugging, only the RecognitionException data fields are transmitted. The token object or whatever that caused the problem was the last object referenced by LT. The immediately preceding LT event should hold the unexpected Token or char. Here is a sample event trace for grammar: b : C ({;}A|B) // {;} is there to prevent A|B becoming a set | D ; The sequence for this rule (with no viable alt in the subrule) for input 'c c' (there are 3 tokens) is: commence LT(1) enterRule b location 7 1 enter decision 3 LT(1) exit decision 3 enterAlt1 location 7 5 LT(1) consumeToken [c/<4>,1:0] location 7 7 enterSubRule 2 enter decision 2 LT(1) LT(1) recognitionException NoViableAltException 2 1 2 exit decision 2 exitSubRule 2 beginResync LT(1) consumeToken [c/<4>,1:1] LT(1) endResync LT(-1) exitRule b terminate
        Specified by:
        recognitionException in interface DebugEventListener
        Overrides:
        recognitionException in class BlankDebugEventListener

      • endResync

        public void endResync()
        Description copied from interface: DebugEventListener
        Indicates that the recognizer has finished consuming tokens in order to resychronize. There may be multiple beginResync/endResync pairs before the recognizer comes out of errorRecovery mode (in which multiple errors are suppressed). This will be useful in a gui where you want to probably grey out tokens that are consumed but not matched to anything in grammar. Anything between a beginResync/endResync pair was tossed out by the parser.
        Specified by:
        endResync in interface DebugEventListener
        Overrides:
        endResync in class BlankDebugEventListener

      • consumeNode

        public void consumeNode​(Object t)
        Description copied from interface: DebugEventListener
        Input for a tree parser is an AST, but we know nothing for sure about a node except its type and text (obtained from the adaptor). This is the analog of the consumeToken method. Again, the ID is the hashCode usually of the node so it only works if hashCode is not implemented. If the type is UP or DOWN, then the ID is not really meaningful as it's fixed--there is just one UP node and one DOWN navigation node.
        Specified by:
        consumeNode in interface DebugEventListener
        Overrides:
        consumeNode in class BlankDebugEventListener

      • LT

        public void LT​(int i,
               Object t)
        Description copied from interface: DebugEventListener
        The tree parser lookedahead. If the type is UP or DOWN, then the ID is not really meaningful as it's fixed--there is just one UP node and one DOWN navigation node.
        Specified by:
        LT in interface DebugEventListener
        Overrides:
        LT in class BlankDebugEventListener

      • nilNode

        public void nilNode​(Object t)
        Description copied from interface: DebugEventListener
        A nil was created (even nil nodes have a unique ID... they are not "null" per se). As of 4/28/2006, this seems to be uniquely triggered when starting a new subtree such as when entering a subrule in automatic mode and when building a tree in rewrite mode. If you are receiving this event over a socket via RemoteDebugEventSocketListener then only t.ID is set.
        Specified by:
        nilNode in interface DebugEventListener
        Overrides:
        nilNode in class BlankDebugEventListener

      • becomeRoot

        public void becomeRoot​(Object newRoot,
                       Object oldRoot)
        Description copied from interface: DebugEventListener
        Make a node the new root of an existing root. See Note: the newRootID parameter is possibly different than the TreeAdaptor.becomeRoot() newRoot parameter. In our case, it will always be the result of calling TreeAdaptor.becomeRoot() and not root_n or whatever. The listener should assume that this event occurs only when the current subrule (or rule) subtree is being reset to newRootID. If you are receiving this event over a socket via RemoteDebugEventSocketListener then only IDs are set.
        Specified by:
        becomeRoot in interface DebugEventListener
        Overrides:
        becomeRoot in class BlankDebugEventListener
        See Also:
        TreeAdaptor.becomeRoot(java.lang.Object, java.lang.Object)

      • setTreeAdaptor

        public void setTreeAdaptor​(TreeAdaptor adaptor)

      • serializeToken

        protected String serializeToken​(Token t)

      • escapeNewlines

        protected String escapeNewlines​(String txt)