Implement new SplitLine method in WritableFrameContainer

Fixes issue 2071, fixes issue 2070

src/com/dmdirc/Channel.java

@@ -163,30 +163,19 @@ public final class Channel extends MessageTarget
             return;
         }
 
-        if (line.indexOf('\n') > -1) {
-            for (String part : line.split("\n")) {
-                sendLine(part);
-            }
-
-            return;
-        }
-
         final ClientInfo me = server.getParser().getMyself();
         final String[] details = getDetails(channelInfo.getUser(me), showColours);
 
-        if (line.length() <= getMaxLineLength()) {
+        for (String part : splitLine(window.getTranscoder().encode(line))) {
             final StringBuffer buff = new StringBuffer("channelSelfMessage");
 
             ActionManager.processEvent(CoreActionType.CHANNEL_SELF_MESSAGE, buff,
-                    this, channelInfo.getUser(me), line);
+                    this, channelInfo.getUser(me), part);
 
             addLine(buff, details[0], details[1], details[2], details[3],
-                    window.getTranscoder().encode(line), channelInfo);
+                    part, channelInfo);
 
-            channelInfo.sendMessage(window.getTranscoder().encode(line));
-        } else {
-            sendLine(line.substring(0, getMaxLineLength()));
-            sendLine(line.substring(getMaxLineLength()));
+            channelInfo.sendMessage(part);
         }
     }
 

src/com/dmdirc/Query.java

@@ -136,28 +136,18 @@ public final class Query extends MessageTarget implements
             return;
         }
 
-        if (line.indexOf('\n') > -1) {
-            for (String part : line.split("\n")) {
-                sendLine(part);
-            }
-
-            return;
-        }
-
         final ClientInfo client = server.getParser().getMyself();
 
-        if (line.length() <= getMaxLineLength()) {
-            server.getParser().sendMessage(ClientInfo.parseHost(host), window.getTranscoder().encode(line));
+        for (String part : splitLine(window.getTranscoder().encode(line))) {
+            server.getParser().sendMessage(ClientInfo.parseHost(host),
+                    part);
 
             final StringBuffer buff = new StringBuffer("querySelfMessage");
 
-            ActionManager.processEvent(CoreActionType.QUERY_SELF_MESSAGE, buff, this, line);
+            ActionManager.processEvent(CoreActionType.QUERY_SELF_MESSAGE, buff, this, part);
 
             addLine(buff, client.getNickname(), client.getIdent(),
-                    client.getHost(), window.getTranscoder().encode(line));
-        } else {
-            sendLine(line.substring(0, getMaxLineLength()));
-            sendLine(line.substring(getMaxLineLength()));
+                    client.getHost(), part);
         }
     }
 

src/com/dmdirc/WritableFrameContainer.java

@@ -81,6 +81,40 @@ public abstract class WritableFrameContainer extends FrameContainer {
      * @return The maximum line length for this container
      */
     public abstract int getMaxLineLength();
+
+    /**
+     * Splits the specified line into chunks that contain a number of bytes
+     * less than or equal to the value returned by {@link #getMaxLineLength()}.
+     *
+     * @param line The line to be split
+     * @return An ordered list of chunks of the desired length
+     */
+    protected List<String> splitLine(final String line) {
+        final List<String> result = new ArrayList<String>();
+
+        if (line.indexOf('\n') > -1) {
+            for (String part : line.split("\n")) {
+                result.addAll(splitLine(part));
+            }
+        } else {
+            final StringBuilder remaining = new StringBuilder(line);
+
+            while (remaining.toString().getBytes().length > getMaxLineLength()) {
+                int number = Math.min(remaining.length(), getMaxLineLength());
+
+                while (remaining.substring(0, number).getBytes().length > getMaxLineLength()) {
+                    number--;
+                }
+
+                result.add(remaining.substring(0, number));
+                remaining.delete(0, number);
+            }
+
+            result.add(remaining.toString());
+        }
+
+        return result;
+    }
     
     /**
      * Returns the number of lines that the specified string would be sent as.

test/com/dmdirc/WritableFrameContainerTest.java

@@ -23,10 +23,8 @@
 package com.dmdirc;
 
 import com.dmdirc.harness.TestWritableFrameContainer;
-import com.dmdirc.config.ConfigManager;
-import com.dmdirc.config.IdentityManager;
-import com.dmdirc.ui.interfaces.InputWindow;
 
+import java.util.Arrays;
 import org.junit.Test;
 import static org.junit.Assert.*;
 
@@ -52,4 +50,27 @@ public class WritableFrameContainerTest extends junit.framework.TestCase {
         assertEquals(2, res2c);        
     }
 
+    @Test
+    public void testSplitLine() {
+        final WritableFrameContainer container10 = new TestWritableFrameContainer(10);
+        final String[][][] tests = new String[][][]{
+            {{""}, {""}},
+            {{"0123456789"}, {"0123456789"}},
+            {{"01234567890"}, {"0123456789", "0"}},
+            {{"012345678→"}, {"012345678","→"}},
+            {{"0123456→"}, {"0123456→"}},
+            {{"01→2345678"}, {"01→23456","78"}},
+            {{"01→23456\n78"}, {"01→23456","78"}},
+            {{"01\n→2345678"}, {"01","→2345678"}},
+            {{"→→→00"}, {"→→→0", "0"}},
+        };
+
+        for (String[][] test : tests) {
+            final String[] res = container10.splitLine(test[0][0]).toArray(new String[0]);
+            assertTrue("'" + test[0][0] + "' → "
+                    + Arrays.toString(res) + " (expected: " + Arrays.toString(test[1]) + ")",
+                    Arrays.equals(res, test[1]));
+        }
+    }
+
 }