From 21b76f1ca10c5612a6db43d517613064bef5ba87 Mon Sep 17 00:00:00 2001
From: zzz <zzz@mail.i2p>
Date: Tue, 14 Jun 2011 19:15:04 +0000
Subject: [PATCH] concurrentify

---
 .../src/net/i2p/util/LogConsoleBuffer.java    | 72 ++++++++++++-------
 core/java/src/net/i2p/util/LogManager.java    |  2 +-
 2 files changed, 46 insertions(+), 28 deletions(-)

diff --git a/core/java/src/net/i2p/util/LogConsoleBuffer.java b/core/java/src/net/i2p/util/LogConsoleBuffer.java
index 2fe2708490..c189f540c8 100644
--- a/core/java/src/net/i2p/util/LogConsoleBuffer.java
+++ b/core/java/src/net/i2p/util/LogConsoleBuffer.java
@@ -2,61 +2,79 @@ package net.i2p.util;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.LinkedBlockingQueue;
 
 import net.i2p.I2PAppContext;
 
 /**
- * Offer a glimpse into the last few console messages generated
- *
+ * Offer a glimpse into the last few console messages generated.
+ * Maintains two buffers, one normal and one critical.
  */
 public class LogConsoleBuffer {
-    private I2PAppContext _context;
-    private final List<String> _buffer;
-    private final List<String> _critBuffer;
+    private final int lim;
+    private final LinkedBlockingQueue<String> _buffer;
+    private final LinkedBlockingQueue<String> _critBuffer;
 
+    /**
+     *  Uses default limit from LogManager.
+     *  As of 0.8.7, limit is not checked at runtime.
+     *
+     *  @param context unused
+     */
     public LogConsoleBuffer(I2PAppContext context) {
-        _context = context;
-        _buffer = new ArrayList();
-        _critBuffer = new ArrayList();
+        this(LogManager.DEFAULT_CONSOLEBUFFERSIZE);
+    }
+
+    /**
+     *  @param limit max size of each buffer
+     *  In theory the limit is configurable, but it isn't in the UI,
+     *  so set it at construction.
+     *
+     *  @since 0.8.7
+     */
+    public LogConsoleBuffer(int limit) {
+        lim = Math.min(limit, 4);
+        // Add some extra room to minimize the chance of losing a message,
+        // since we are doing offer() below.
+        _buffer = new LinkedBlockingQueue(limit + 4);
+        _critBuffer = new LinkedBlockingQueue(limit + 4);
     }
 
     void add(String msg) {
-        int lim = _context.logManager().getConsoleBufferSize();
-        synchronized (_buffer) {
             while (_buffer.size() >= lim)
-                _buffer.remove(0);
-            _buffer.add(msg);
-        }
-    }
-    void addCritical(String msg) {
-        int lim = _context.logManager().getConsoleBufferSize();
-        synchronized (_critBuffer) {
-            while (_critBuffer.size() >= lim)
-                _critBuffer.remove(0);
-            _critBuffer.add(msg);
-        }
+                _buffer.poll();
+            _buffer.offer(msg);
     }
 
     /**
-     * Retrieve the currently bufferd messages, earlier values were generated...
+     *  Only adds to the critical buffer, not to both.
+     *
+     */
+    void addCritical(String msg) {
+            while (_critBuffer.size() >= lim)
+                _critBuffer.poll();
+            _critBuffer.offer(msg);
+    }
+
+    /**
+     * Retrieve the currently buffered messages, earlier values were generated...
      * earlier.  All values are strings with no formatting (as they are written
      * in the logs)
      *
+     * @return oldest first
      */
     public List<String> getMostRecentMessages() {
-        synchronized (_buffer) {
             return new ArrayList(_buffer);
-        }
     }
+
     /**
-     * Retrieve the currently bufferd crutucak messages, earlier values were generated...
+     * Retrieve the currently buffered critical messages, earlier values were generated...
      * earlier.  All values are strings with no formatting (as they are written
      * in the logs)
      *
+     * @return oldest first
      */
     public List<String> getMostRecentCriticalMessages() {
-        synchronized (_critBuffer) {
             return new ArrayList(_critBuffer);
-        }
     }
 }
diff --git a/core/java/src/net/i2p/util/LogManager.java b/core/java/src/net/i2p/util/LogManager.java
index b7d280491f..6e8655588c 100644
--- a/core/java/src/net/i2p/util/LogManager.java
+++ b/core/java/src/net/i2p/util/LogManager.java
@@ -129,7 +129,7 @@ public class LogManager {
         _log = getLog(LogManager.class);
         String location = context.getProperty(CONFIG_LOCATION_PROP, CONFIG_LOCATION_DEFAULT);
         setConfig(location);
-        _consoleBuffer = new LogConsoleBuffer(context);
+        _consoleBuffer = new LogConsoleBuffer(_consoleBufferSize);
         // If we aren't in the router context, delay creating the LogWriter until required,
         // so it doesn't create a log directory and log files unless there is output.
         // In the router context, we have to rotate to a new log file at startup or the logs.jsp