add new writeLogTo method

core/src/main/java/org/kohsuke/stapler/framework/io/LargeText.java

@@ -193,6 +193,13 @@ public void close() throws IOException {
     public long writeLogTo(long start, Writer w) throws IOException {
         return writeLogTo(start, new WriterOutputStream(w, charset));
     }
+
+    /**
+    *  add end parameter to avoid large log file cause memory leak
+    **/
+    public long writeLogTo(long start,long end, Writer w) throws IOException {
+        return writeLogTo(start, end,new WriterOutputStream(w, charset));
+    }
 
     /**
      * Writes the tail portion of the file to the {@link OutputStream}.
@@ -236,6 +243,47 @@ public long writeLogTo(long start, OutputStream out) throws IOException {
 
         return os.getByteCount()+start;
     }
+
+    /**
+    *  add end parameter to avoid large log file cause memory leak
+    **/
+    public long writeLogTo(long start,long end, OutputStream out) throws IOException {
+        CountingOutputStream os = new CountingOutputStream(out);
+
+        Session f = source.open();
+        f.skip(start);
+
+        if(completed) {
+            // write everything till EOF
+            byte[] buf = new byte[1024];
+            int sz;
+            while((sz=f.read(buf))>=0) {
+                os.write(buf,0,sz);
+            	if(os.getCount()>end) {
+            		break;
+            	}
+            }
+        } else {
+            ByteBuf buf = new ByteBuf(null,f);
+            HeadMark head = new HeadMark(buf);
+            TailMark tail = new TailMark(buf);
+            buf = null;
+
+            int readLines = 0;
+            while(tail.moveToNextLine(f) && readLines++ < MAX_LINES_READ) {
+            	head.moveTo(tail,os);
+                if(os.getCount()>end) {
+            		break;
+            	}
+            }
+            head.finish(os);
+        }
+
+        f.close();
+        os.flush();
+
+        return os.getByteCount()+start;
+    }
 
     /**
      * Implements the progressive text handling.