# HG changeset patch
# User Artem Tikhomirov <tikhomirov.artem@gmail.com>
# Date 1321328823 -3600
# Node ID 3cfa4d908fc9c8d8f4155d95d4edb9b30dc10759
# Parent  f377f833b78098c313f8611fa35ed2b832d47767
Add options to control DataAccessProvider, allow to turn off use of file memory mapping in particular to solve potential sharing violation (os file handle gets released on MappedByteByffer being GC'd, not on FileChannel.close())

diff -r f377f833b780 -r 3cfa4d908fc9 src/org/tmatesoft/hg/core/SessionContext.java
--- a/src/org/tmatesoft/hg/core/SessionContext.java	Tue Nov 15 03:07:28 2011 +0100
+++ b/src/org/tmatesoft/hg/core/SessionContext.java	Tue Nov 15 04:47:03 2011 +0100
@@ -31,4 +31,9 @@
 @Experimental(reason="Work in progress")
 public interface SessionContext {
 	LogFacility getLog();
+	
+	/**
+	 * LIKELY TO CHANGE TO STANDALONE CONFIGURATION OBJECT
+	 */
+	Object getProperty(String name, Object defaultValue);
 }
diff -r f377f833b780 -r 3cfa4d908fc9 src/org/tmatesoft/hg/internal/BasicSessionContext.java
--- a/src/org/tmatesoft/hg/internal/BasicSessionContext.java	Tue Nov 15 03:07:28 2011 +0100
+++ b/src/org/tmatesoft/hg/internal/BasicSessionContext.java	Tue Nov 15 04:47:03 2011 +0100
@@ -48,4 +48,8 @@
 		return logFacility;
 	}
 
+	public Object getProperty(String name, Object defaultValue) {
+		String value = System.getProperty(name);
+		return value == null ? defaultValue : value;
+	}
 }
diff -r f377f833b780 -r 3cfa4d908fc9 src/org/tmatesoft/hg/internal/DataAccessProvider.java
--- a/src/org/tmatesoft/hg/internal/DataAccessProvider.java	Tue Nov 15 03:07:28 2011 +0100
+++ b/src/org/tmatesoft/hg/internal/DataAccessProvider.java	Tue Nov 15 04:47:03 2011 +0100
@@ -32,18 +32,34 @@
  * @author TMate Software Ltd.
  */
 public class DataAccessProvider {
+	/**
+	 * Boundary to start using file memory mapping instead of regular file access, in bytes.  
+	 * Set to 0 to indicate mapping files into memory shall not be used.
+	 * If set to -1, file of any size would be mapped in memory.
+	 */
+	public static final String CFG_PROPERTY_MAPIO_LIMIT				= "hg4j.dap.mapio_limit";
+	public static final String CFG_PROPERTY_MAPIO_BUFFER_SIZE		= "hg4j.dap.mapio_buffer";
+	public static final String CFG_PROPERTY_FILE_BUFFER_SIZE		= "hg4j.dap.file_buffer";
 
 	private final int mapioMagicBoundary;
 	private final int bufferSize;
 	private final SessionContext context;
 
 	public DataAccessProvider(SessionContext ctx) {
-		this(ctx, 100 * 1024, 8 * 1024);
+		this(ctx, getConfigOption(ctx, CFG_PROPERTY_MAPIO_LIMIT, 100 * 1024), getConfigOption(ctx, CFG_PROPERTY_FILE_BUFFER_SIZE, 8 * 1024));
+	}
+	
+	private static int getConfigOption(SessionContext ctx, String optName, int defaultValue) {
+		Object v = ctx.getProperty(optName, defaultValue);
+		if (false == v instanceof Number) {
+			v = Integer.parseInt(v.toString());
+		}
+		return ((Number) v).intValue();
 	}
 
 	public DataAccessProvider(SessionContext ctx, int mapioBoundary, int regularBufferSize) {
 		context = ctx;
-		mapioMagicBoundary = mapioBoundary;
+		mapioMagicBoundary = mapioBoundary == 0 ? Integer.MAX_VALUE : mapioBoundary;
 		bufferSize = regularBufferSize;
 	}
 
@@ -59,12 +75,12 @@
 			}
 			if (flen > mapioMagicBoundary) {
 				// TESTS: bufLen of 1024 was used to test MemMapFileAccess
-				return new MemoryMapFileAccess(fc, flen, mapioMagicBoundary);
+				return new MemoryMapFileAccess(fc, flen, getConfigOption(context, CFG_PROPERTY_MAPIO_BUFFER_SIZE, 100*1024 /*same as default boundary*/));
 			} else {
 				// XXX once implementation is more or less stable,
 				// may want to try ByteBuffer.allocateDirect() to see
 				// if there's any performance gain. 
-				boolean useDirectBuffer = false;
+				boolean useDirectBuffer = false; // XXX might be another config option
 				// TESTS: bufferSize of 100 was used to check buffer underflow states when readBytes reads chunks bigger than bufSize
 				return new FileAccess(fc, flen, bufferSize, useDirectBuffer);
 			}
@@ -83,10 +99,10 @@
 		private final int memBufferSize;
 		private MappedByteBuffer buffer;
 
-		public MemoryMapFileAccess(FileChannel fc, int channelSize, int /*long?*/ bufferSize) {
+		public MemoryMapFileAccess(FileChannel fc, int channelSize, int bufferSize) {
 			fileChannel = fc;
 			size = channelSize;
-			memBufferSize = bufferSize;
+			memBufferSize = bufferSize > channelSize ? channelSize : bufferSize; // no reason to waste memory more than there's data 
 		}
 
 		@Override