1 files changed, 145 insertions, 0 deletions
diff --git a/plugins/org.eclipse.tcf.core/src/org/eclipse/tcf/core/StreamChannel.java b/plugins/org.eclipse.tcf.core/src/org/eclipse/tcf/core/StreamChannel.java
new file mode 100644
index 000000000..841e53fc6
--- /dev/null
+++ b/plugins/org.eclipse.tcf.core/src/org/eclipse/tcf/core/StreamChannel.java
@@ -0,0 +1,145 @@
+/*******************************************************************************
+ * Copyright (c) 2007, 2010 Wind River Systems, Inc. and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     Wind River Systems - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.tm.tcf.core;
+
+import java.io.IOException;
+
+import org.eclipse.tm.tcf.protocol.IPeer;
+
+/**
+ * Abstract implementation of IChannel interface for stream oriented transport protocols.
+ *
+ * StreamChannel implements communication link connecting two end points (peers).
+ * The channel asynchronously transmits messages: commands, results and events.
+ *
+ * StreamChannel uses escape sequences to represent End-Of-Message and End-Of-Stream markers.
+ *
+ * Clients can subclass StreamChannel to support particular stream oriented transport (wire) protocol.
+ * Also, see ChannelTCP for a concrete IChannel implementation that works on top of TCP sockets as a transport.
+ */
+public abstract class StreamChannel extends AbstractChannel {
+
+    public static final int ESC = 3;
+
+    private int bin_data_size;
+
+    private final byte[] buf = new byte[0x1000];
+    private int buf_pos;
+    private int buf_len;
+
+    public StreamChannel(IPeer remote_peer) {
+        super(remote_peer);
+    }
+
+    public StreamChannel(IPeer local_peer, IPeer remote_peer) {
+        super(local_peer, remote_peer);
+    }
+
+    protected abstract int get() throws IOException;
+    protected abstract void put(int n) throws IOException;
+
+    protected int get(byte[] buf) throws IOException {
+        int i = 0;
+        while (i < buf.length) {
+            int b = get();
+            if (b < 0) {
+                if (i == 0) return -1;
+                break;
+            }
+            buf[i++] = (byte)b;
+            if (i >= bin_data_size) break;
+        }
+        return i;
+    }
+
+    protected void put(byte[] buf) throws IOException {
+        for (byte b : buf) put(b & 0xff);
+    }
+
+    @Override
+    protected final int read() throws IOException {
+        for (;;) {
+            while (buf_pos >= buf_len) {
+                buf_len = get(buf);
+                buf_pos = 0;
+                if (buf_len < 0) return EOS;
+            }
+            int res = buf[buf_pos++] & 0xff;
+            if (bin_data_size > 0) {
+                bin_data_size--;
+                return res;
+            }
+            if (res != ESC) return res;
+            while (buf_pos >= buf_len) {
+                buf_len = get(buf);
+                buf_pos = 0;
+                if (buf_len < 0) return EOS;
+            }
+            int n = buf[buf_pos++] & 0xff;
+            switch (n) {
+            case 0: return ESC;
+            case 1: return EOM;
+            case 2: return EOS;
+            case 3:
+                for (int i = 0;; i += 7) {
+                    while (buf_pos >= buf_len) {
+                        buf_len = get(buf);
+                        buf_pos = 0;
+                        if (buf_len < 0) return EOS;
+                    }
+                    int m = buf[buf_pos++] & 0xff;
+                    bin_data_size |= (m & 0x7f) << i;
+                    if ((m & 0x80) == 0) break;
+                }
+                break;
+            default:
+                if (n < 0) return EOS;
+                assert false;
+            }
+        }
+    }
+
+    @Override
+    protected final void write(int n) throws IOException {
+        switch (n) {
+        case ESC: put(ESC); put(0); break;
+        case EOM: put(ESC); put(1); break;
+        case EOS: put(ESC); put(2); break;
+        default:
+            assert n >= 0 && n <= 0xff;
+            put(n);
+        }
+    }
+
+    @Override
+    protected void write(byte[] buf) throws IOException {
+        if (buf.length > 32 && isZeroCopySupported()) {
+            put(ESC); put(3);
+            int n = buf.length;
+            for (;;) {
+                if (n <= 0x7f) {
+                    put(n);
+                    break;
+                }
+                put((n & 0x7f) | 0x80);
+                n = n >> 7;
+            }
+            put(buf);
+        }
+        else {
+            for (byte b : buf) {
+                int n = b & 0xff;
+                put(n);
+                if (n == ESC) put(0);
+            }
+        }
+    }
+}