Fix: Correctly compute Java agent list loggers response size

[lttng-ust.git] / liblttng-ust-java-agent / java / lttng-ust-agent-common / org / lttng / ust / agent / client / SessiondListLoggersCommand.java

diff --git a/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/client/SessiondListLoggersCommand.java b/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/client/SessiondListLoggersCommand.java
index 1c7ef9b400f019e7611c36b5bb349c99cc628b5d..4dee6ae406c954466899357c0020257e41ddc49f 100644 (file)
--- a/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/client/SessiondListLoggersCommand.java
+++ b/liblttng-ust-java-agent/java/lttng-ust-agent-common/org/lttng/ust/agent/client/SessiondListLoggersCommand.java
@@ -34,13 +34,7 @@ class SessiondListLoggersCommand extends SessiondCommand {
        @Override
        public LttngAgentResponse execute(ILttngTcpClientListener agent) {
                final Collection<String> loggerList = agent.listAvailableEvents();
-               int dataSize = 0;
-
-               for (String event : agent.listAvailableEvents()) {
-                       dataSize += event.length() + 1;
-               }
-
-               return new SessiondListLoggersResponse(loggerList, dataSize);
+               return new SessiondListLoggersResponse(loggerList);
        }
 
        private static class SessiondListLoggersResponse extends LttngAgentResponse {
@@ -48,11 +42,9 @@ class SessiondListLoggersCommand extends SessiondCommand {
                private final static int SIZE = 12;
 
                private final Collection<String> loggers;
-               private final int dataSize;
 
-               public SessiondListLoggersResponse(Collection<String> loggers, int dataSize) {
+               public SessiondListLoggersResponse(Collection<String> loggers) {
                        this.loggers = loggers;
-                       this.dataSize = dataSize;
                }
 
                @Override
@@ -63,15 +55,26 @@ class SessiondListLoggersCommand extends SessiondCommand {
 
                @Override
                public byte[] getBytes() {
+                       /*
+                        * Compute the data size, which is the number of bytes of each
+                        * encoded string, +1 per string for the \0
+                        */
+                       int dataSize = 0;
+                       for (String logger : loggers) {
+                               dataSize += logger.getBytes(SESSIOND_PROTOCOL_CHARSET).length + 1;
+                       }
+
+                       /* Prepare the buffer */
                        byte data[] = new byte[SIZE + dataSize];
                        ByteBuffer buf = ByteBuffer.wrap(data);
                        buf.order(ByteOrder.BIG_ENDIAN);
 
-                       /* Returned code */
+                       /* Write the header section of the response */
                        buf.putInt(getReturnCode().getCode());
                        buf.putInt(dataSize);
                        buf.putInt(loggers.size());
 
+                       /* Write the payload */
                        for (String logger : loggers) {
                                buf.put(logger.getBytes(SESSIOND_PROTOCOL_CHARSET));
                                /* NULL terminated byte after the logger name. */