org.eclipse.jgit/src/org/eclipse/jgit/storage/file/WindowCacheConfig.java - jgit - Git at Google

 /*
  * Copyright (C) 2009, Google Inc. and others
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Distribution License v. 1.0 which is available at
  * https://www.eclipse.org/org/documents/edl-v10.php.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */

 package org.eclipse.jgit.storage.file;

 import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_CORE_SECTION;
 import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_DELTA_BASE_CACHE_LIMIT;
 import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_PACKED_GIT_LIMIT;
 import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_PACKED_GIT_MMAP;
 import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_PACKED_GIT_OPENFILES;
 import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_PACKED_GIT_WINDOWSIZE;
 import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_STREAM_FILE_THRESHOLD;
 import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_PACKED_GIT_USE_STRONGREFS;
 import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_PACKED_INDEX_GIT_USE_STRONGREFS;

 import org.eclipse.jgit.internal.storage.file.WindowCache;
 import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.storage.pack.PackConfig;

 /**
  * Configuration parameters for JVM-wide buffer cache used by JGit.
  */
 public class WindowCacheConfig {
 	/** 1024 (number of bytes in one kibibyte/kilobyte) */
 	public static final int KB = 1024;

 	/** 1024 {@link #KB} (number of bytes in one mebibyte/megabyte) */
 	public static final int MB = 1024 * KB;

 	private int packedGitOpenFiles;

 	private long packedGitLimit;

 	private boolean useStrongRefs;

 	private boolean useStrongIndexRefs;

 	private int packedGitWindowSize;

 	private boolean packedGitMMAP;

 	private int deltaBaseCacheLimit;

 	private int streamFileThreshold;

 	private boolean exposeStats;

 	/**
 	 * Create a default configuration.
 	 */
 	public WindowCacheConfig() {
 		packedGitOpenFiles = 128;
 		packedGitLimit = 10 * MB;
 		useStrongRefs = false;
 		useStrongIndexRefs = true;
 		packedGitWindowSize = 8 * KB;
 		packedGitMMAP = false;
 		deltaBaseCacheLimit = 10 * MB;
 		streamFileThreshold = PackConfig.DEFAULT_BIG_FILE_THRESHOLD;
 		exposeStats = true;
 	}

 	/**
 	 * Get maximum number of streams to open at a time.
 	 *
 	 * @return maximum number of streams to open at a time. Open packs count
 	 *         against the process limits. <b>Default is 128.</b>
 	 */
 	public int getPackedGitOpenFiles() {
 		return packedGitOpenFiles;
 	}

 	/**
 	 * Set maximum number of streams to open at a time.
 	 *
 	 * @param fdLimit
 	 *            maximum number of streams to open at a time. Open packs count
 	 *            against the process limits
 	 */
 	public void setPackedGitOpenFiles(int fdLimit) {
 		packedGitOpenFiles = fdLimit;
 	}

 	/**
 	 * Get maximum number bytes of heap memory to dedicate to caching pack file
 	 * data.
 	 *
 	 * @return maximum number bytes of heap memory to dedicate to caching pack
 	 *         file data. <b>Default is 10 MB.</b>
 	 */
 	public long getPackedGitLimit() {
 		return packedGitLimit;
 	}

 	/**
 	 * Set maximum number bytes of heap memory to dedicate to caching pack file
 	 * data.
 	 *
 	 * @param newLimit
 	 *            maximum number bytes of heap memory to dedicate to caching
 	 *            pack file data.
 	 */
 	public void setPackedGitLimit(long newLimit) {
 		packedGitLimit = newLimit;
 	}

 	/**
 	 * Get whether the window cache should use strong references or
 	 * SoftReferences
 	 *
 	 * @return {@code true} if the window cache should use strong references,
 	 *         otherwise it will use {@link java.lang.ref.SoftReference}s
 	 * @since 5.1.13
 	 */
 	public boolean isPackedGitUseStrongRefs() {
 		return useStrongRefs;
 	}

 	/**
 	 * Set if the cache should use strong refs or soft refs
 	 *
 	 * @param useStrongRefs
 	 *            if @{code true} the cache strongly references cache pages
 	 *            otherwise it uses {@link java.lang.ref.SoftReference}s which
 	 *            can be evicted by the Java gc if heap is almost full
 	 * @since 5.1.13
 	 */
 	public void setPackedGitUseStrongRefs(boolean useStrongRefs) {
 		this.useStrongRefs = useStrongRefs;
 	}

 	/**
 	 * Get whether the Pack indices cache should use strong references or
 	 * SoftReferences
 	 *
 	 * @return {@code true} if the cached Pack indices should use strong references,
 	 *         otherwise it will use {@link java.lang.ref.SoftReference}s
 	 * @since 6.7
 	 */
 	public boolean isPackedIndexGitUseStrongRefs() {
 		return useStrongIndexRefs;
 	}

 	/**
 	 * Set if the Pack indices cache should use strong refs or soft refs
 	 *
 	 * @param useStrongRefs
 	 *            if @{code true} the Pack strongly references cached indices
 	 *            otherwise it uses {@link java.lang.ref.SoftReference}s which
 	 *            can be evicted by the Java gc if heap is almost full
 	 * @since 6.7
 	 */
 	public void setPackedIndexGitUseStrongRefs(boolean useStrongRefs) {
 		this.useStrongIndexRefs = useStrongRefs;
 	}

 	/**
 	 * Get size in bytes of a single window mapped or read in from the pack
 	 * file.
 	 *
 	 * @return size in bytes of a single window mapped or read in from the pack
 	 *         file. <b>Default is 8 KB.</b>
 	 */
 	public int getPackedGitWindowSize() {
 		return packedGitWindowSize;
 	}

 	/**
 	 * Set size in bytes of a single window read in from the pack file.
 	 *
 	 * @param newSize
 	 *            size in bytes of a single window read in from the pack file.
 	 */
 	public void setPackedGitWindowSize(int newSize) {
 		packedGitWindowSize = newSize;
 	}

 	/**
 	 * Whether to use Java NIO virtual memory mapping for windows
 	 *
 	 * @return {@code true} enables use of Java NIO virtual memory mapping for
 	 *         windows; false reads entire window into a byte[] with standard
 	 *         read calls. <b>Default false.</b>
 	 */
 	public boolean isPackedGitMMAP() {
 		return packedGitMMAP;
 	}

 	/**
 	 * Set whether to enable use of Java NIO virtual memory mapping for windows
 	 *
 	 * @param usemmap
 	 *            {@code true} enables use of Java NIO virtual memory mapping
 	 *            for windows; false reads entire window into a byte[] with
 	 *            standard read calls.
 	 */
 	public void setPackedGitMMAP(boolean usemmap) {
 		packedGitMMAP = usemmap;
 	}

 	/**
 	 * Get maximum number of bytes to cache in delta base cache for inflated,
 	 * recently accessed objects, without delta chains.
 	 *
 	 * @return maximum number of bytes to cache in delta base cache for
 	 *         inflated, recently accessed objects, without delta chains.
 	 *         <b>Default 10 MB.</b>
 	 */
 	public int getDeltaBaseCacheLimit() {
 		return deltaBaseCacheLimit;
 	}

 	/**
 	 * Set maximum number of bytes to cache in delta base cache for inflated,
 	 * recently accessed objects, without delta chains.
 	 *
 	 * @param newLimit
 	 *            maximum number of bytes to cache in delta base cache for
 	 *            inflated, recently accessed objects, without delta chains.
 	 */
 	public void setDeltaBaseCacheLimit(int newLimit) {
 		deltaBaseCacheLimit = newLimit;
 	}

 	/**
 	 * Get the size threshold beyond which objects must be streamed.
 	 *
 	 * @return the size threshold beyond which objects must be streamed.
 	 */
 	public int getStreamFileThreshold() {
 		return streamFileThreshold;
 	}

 	/**
 	 * Set new byte limit for objects that must be streamed.
 	 *
 	 * @param newLimit
 	 *            new byte limit for objects that must be streamed. Objects
 	 *            smaller than this size can be obtained as a contiguous byte
 	 *            array, while objects bigger than this size require using an
 	 *            {@link org.eclipse.jgit.lib.ObjectStream}.
 	 */
 	public void setStreamFileThreshold(int newLimit) {
 		streamFileThreshold = newLimit;
 	}

 	/**
 	 * Tell whether the statistics JMX bean should be automatically registered.
 	 * <p>
 	 * Registration of that bean via JMX is additionally subject to a boolean
 	 * JGit-specific user config "jmx.WindowCacheStats". The bean will be
 	 * registered only if this user config is {@code true} <em>and</em>
 	 * {@code getExposeStatsViaJmx() == true}.
 	 * </p>
 	 * <p>
 	 * By default, this returns {@code true} unless changed via
 	 * {@link #setExposeStatsViaJmx(boolean)}.
 	 *
 	 * @return whether to expose WindowCacheStats statistics via JMX upon
 	 *         {@link #install()}
 	 * @since 5.8
 	 */
 	public boolean getExposeStatsViaJmx() {
 		return exposeStats;
 	}

 	/**
 	 * Defines whether the statistics JMX MBean should be automatically set up.
 	 * (By default {@code true}.) If set to {@code false}, the JMX monitoring
 	 * bean is not registered.
 	 *
 	 * @param expose
 	 *            whether to register the JMX Bean
 	 * @since 5.8
 	 */
 	public void setExposeStatsViaJmx(boolean expose) {
 		exposeStats = expose;
 	}

 	/**
 	 * Update properties by setting fields from the configuration.
 	 * <p>
 	 * If a property is not defined in the configuration, then it is left
 	 * unmodified.
 	 *
 	 * @param rc
 	 *            configuration to read properties from.
 	 * @return {@code this}.
 	 * @since 3.0
 	 */
 	public WindowCacheConfig fromConfig(Config rc) {
 		setPackedGitUseStrongRefs(rc.getBoolean(CONFIG_CORE_SECTION,
 				CONFIG_KEY_PACKED_GIT_USE_STRONGREFS,
 				isPackedGitUseStrongRefs()));
 		setPackedIndexGitUseStrongRefs(rc.getBoolean(CONFIG_CORE_SECTION,
 				CONFIG_KEY_PACKED_INDEX_GIT_USE_STRONGREFS, isPackedIndexGitUseStrongRefs()));
 		setPackedGitOpenFiles(rc.getInt(CONFIG_CORE_SECTION, null,
 				CONFIG_KEY_PACKED_GIT_OPENFILES, getPackedGitOpenFiles()));
 		setPackedGitLimit(rc.getLong(CONFIG_CORE_SECTION, null,
 				CONFIG_KEY_PACKED_GIT_LIMIT, getPackedGitLimit()));
 		setPackedGitWindowSize(rc.getInt(CONFIG_CORE_SECTION, null,
 				CONFIG_KEY_PACKED_GIT_WINDOWSIZE, getPackedGitWindowSize()));
 		setPackedGitMMAP(rc.getBoolean(CONFIG_CORE_SECTION, null,
 				CONFIG_KEY_PACKED_GIT_MMAP, isPackedGitMMAP()));
 		setDeltaBaseCacheLimit(rc.getInt(CONFIG_CORE_SECTION, null,
 				CONFIG_KEY_DELTA_BASE_CACHE_LIMIT, getDeltaBaseCacheLimit()));

 		long maxMem = Runtime.getRuntime().maxMemory();
 		long sft = rc.getLong(CONFIG_CORE_SECTION, null,
 				CONFIG_KEY_STREAM_FILE_THRESHOLD, getStreamFileThreshold());
 		sft = Math.min(sft, maxMem / 4); // don't use more than 1/4 of the heap
 		sft = Math.min(sft, Integer.MAX_VALUE); // cannot exceed array length
 		setStreamFileThreshold((int) sft);
 		return this;
 	}

 	/**
 	 * Install this configuration as the live settings.
 	 * <p>
 	 * The new configuration is applied immediately. If the new limits are
 	 * smaller than what is currently cached, older entries will be purged
 	 * as soon as possible to allow the cache to meet the new limit.
 	 *
 	 * @since 3.0
 	 */
 	@SuppressWarnings("deprecation")
 	public void install() {
 		WindowCache.reconfigure(this);
 	}
 }
	/*
	* Copyright (C) 2009, Google Inc. and others
	*
	* This program and the accompanying materials are made available under the
	* terms of the Eclipse Distribution License v. 1.0 which is available at
	* https://www.eclipse.org/org/documents/edl-v10.php.
	*
	* SPDX-License-Identifier: BSD-3-Clause
	*/

	package org.eclipse.jgit.storage.file;

	import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_CORE_SECTION;
	import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_DELTA_BASE_CACHE_LIMIT;
	import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_PACKED_GIT_LIMIT;
	import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_PACKED_GIT_MMAP;
	import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_PACKED_GIT_OPENFILES;
	import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_PACKED_GIT_WINDOWSIZE;
	import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_STREAM_FILE_THRESHOLD;
	import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_PACKED_GIT_USE_STRONGREFS;
	import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_PACKED_INDEX_GIT_USE_STRONGREFS;

	import org.eclipse.jgit.internal.storage.file.WindowCache;
	import org.eclipse.jgit.lib.Config;
	import org.eclipse.jgit.storage.pack.PackConfig;

	/**
	* Configuration parameters for JVM-wide buffer cache used by JGit.
	*/
	public class WindowCacheConfig {
	/** 1024 (number of bytes in one kibibyte/kilobyte) */
	public static final int KB = 1024;

	/** 1024 {@link #KB} (number of bytes in one mebibyte/megabyte) */
	public static final int MB = 1024 * KB;

	private int packedGitOpenFiles;

	private long packedGitLimit;

	private boolean useStrongRefs;

	private boolean useStrongIndexRefs;

	private int packedGitWindowSize;

	private boolean packedGitMMAP;

	private int deltaBaseCacheLimit;

	private int streamFileThreshold;

	private boolean exposeStats;

	/**
	* Create a default configuration.
	*/
	public WindowCacheConfig() {
	packedGitOpenFiles = 128;
	packedGitLimit = 10 * MB;
	useStrongRefs = false;
	useStrongIndexRefs = true;
	packedGitWindowSize = 8 * KB;
	packedGitMMAP = false;
	deltaBaseCacheLimit = 10 * MB;
	streamFileThreshold = PackConfig.DEFAULT_BIG_FILE_THRESHOLD;
	exposeStats = true;
	}

	/**
	* Get maximum number of streams to open at a time.
	*
	* @return maximum number of streams to open at a time. Open packs count
	* against the process limits. <b>Default is 128.</b>
	*/
	public int getPackedGitOpenFiles() {
	return packedGitOpenFiles;
	}

	/**
	* Set maximum number of streams to open at a time.
	*
	* @param fdLimit
	* maximum number of streams to open at a time. Open packs count
	* against the process limits
	*/
	public void setPackedGitOpenFiles(int fdLimit) {
	packedGitOpenFiles = fdLimit;
	}

	/**
	* Get maximum number bytes of heap memory to dedicate to caching pack file
	* data.
	*
	* @return maximum number bytes of heap memory to dedicate to caching pack
	* file data. <b>Default is 10 MB.</b>
	*/
	public long getPackedGitLimit() {
	return packedGitLimit;
	}

	/**
	* Set maximum number bytes of heap memory to dedicate to caching pack file
	* data.
	*
	* @param newLimit
	* maximum number bytes of heap memory to dedicate to caching
	* pack file data.
	*/
	public void setPackedGitLimit(long newLimit) {
	packedGitLimit = newLimit;
	}

	/**
	* Get whether the window cache should use strong references or
	* SoftReferences
	*
	* @return {@code true} if the window cache should use strong references,
	* otherwise it will use {@link java.lang.ref.SoftReference}s
	* @since 5.1.13
	*/
	public boolean isPackedGitUseStrongRefs() {
	return useStrongRefs;
	}

	/**
	* Set if the cache should use strong refs or soft refs
	*
	* @param useStrongRefs
	* if @{code true} the cache strongly references cache pages
	* otherwise it uses {@link java.lang.ref.SoftReference}s which
	* can be evicted by the Java gc if heap is almost full
	* @since 5.1.13
	*/
	public void setPackedGitUseStrongRefs(boolean useStrongRefs) {
	this.useStrongRefs = useStrongRefs;
	}

	/**
	* Get whether the Pack indices cache should use strong references or
	* SoftReferences
	*
	* @return {@code true} if the cached Pack indices should use strong references,
	* otherwise it will use {@link java.lang.ref.SoftReference}s
	* @since 6.7
	*/
	public boolean isPackedIndexGitUseStrongRefs() {
	return useStrongIndexRefs;
	}

	/**
	* Set if the Pack indices cache should use strong refs or soft refs
	*
	* @param useStrongRefs
	* if @{code true} the Pack strongly references cached indices
	* otherwise it uses {@link java.lang.ref.SoftReference}s which
	* can be evicted by the Java gc if heap is almost full
	* @since 6.7
	*/
	public void setPackedIndexGitUseStrongRefs(boolean useStrongRefs) {
	this.useStrongIndexRefs = useStrongRefs;
	}

	/**
	* Get size in bytes of a single window mapped or read in from the pack
	* file.
	*
	* @return size in bytes of a single window mapped or read in from the pack
	* file. <b>Default is 8 KB.</b>
	*/
	public int getPackedGitWindowSize() {
	return packedGitWindowSize;
	}

	/**
	* Set size in bytes of a single window read in from the pack file.
	*
	* @param newSize
	* size in bytes of a single window read in from the pack file.
	*/
	public void setPackedGitWindowSize(int newSize) {
	packedGitWindowSize = newSize;
	}

	/**
	* Whether to use Java NIO virtual memory mapping for windows
	*
	* @return {@code true} enables use of Java NIO virtual memory mapping for
	* windows; false reads entire window into a byte[] with standard
	* read calls. <b>Default false.</b>
	*/
	public boolean isPackedGitMMAP() {
	return packedGitMMAP;
	}

	/**
	* Set whether to enable use of Java NIO virtual memory mapping for windows
	*
	* @param usemmap
	* {@code true} enables use of Java NIO virtual memory mapping
	* for windows; false reads entire window into a byte[] with
	* standard read calls.
	*/
	public void setPackedGitMMAP(boolean usemmap) {
	packedGitMMAP = usemmap;
	}

	/**
	* Get maximum number of bytes to cache in delta base cache for inflated,
	* recently accessed objects, without delta chains.
	*
	* @return maximum number of bytes to cache in delta base cache for
	* inflated, recently accessed objects, without delta chains.
	* <b>Default 10 MB.</b>
	*/
	public int getDeltaBaseCacheLimit() {
	return deltaBaseCacheLimit;
	}

	/**
	* Set maximum number of bytes to cache in delta base cache for inflated,
	* recently accessed objects, without delta chains.
	*
	* @param newLimit
	* maximum number of bytes to cache in delta base cache for
	* inflated, recently accessed objects, without delta chains.
	*/
	public void setDeltaBaseCacheLimit(int newLimit) {
	deltaBaseCacheLimit = newLimit;
	}

	/**
	* Get the size threshold beyond which objects must be streamed.
	*
	* @return the size threshold beyond which objects must be streamed.
	*/
	public int getStreamFileThreshold() {
	return streamFileThreshold;
	}

	/**
	* Set new byte limit for objects that must be streamed.
	*
	* @param newLimit
	* new byte limit for objects that must be streamed. Objects
	* smaller than this size can be obtained as a contiguous byte
	* array, while objects bigger than this size require using an
	* {@link org.eclipse.jgit.lib.ObjectStream}.
	*/
	public void setStreamFileThreshold(int newLimit) {
	streamFileThreshold = newLimit;
	}

	/**
	* Tell whether the statistics JMX bean should be automatically registered.
	* <p>
	* Registration of that bean via JMX is additionally subject to a boolean
	* JGit-specific user config "jmx.WindowCacheStats". The bean will be
	* registered only if this user config is {@code true} <em>and</em>
	* {@code getExposeStatsViaJmx() == true}.
	* </p>
	* <p>
	* By default, this returns {@code true} unless changed via
	* {@link #setExposeStatsViaJmx(boolean)}.
	*
	* @return whether to expose WindowCacheStats statistics via JMX upon
	* {@link #install()}
	* @since 5.8
	*/
	public boolean getExposeStatsViaJmx() {
	return exposeStats;
	}

	/**
	* Defines whether the statistics JMX MBean should be automatically set up.
	* (By default {@code true}.) If set to {@code false}, the JMX monitoring
	* bean is not registered.
	*
	* @param expose
	* whether to register the JMX Bean
	* @since 5.8
	*/
	public void setExposeStatsViaJmx(boolean expose) {
	exposeStats = expose;
	}

	/**
	* Update properties by setting fields from the configuration.
	* <p>
	* If a property is not defined in the configuration, then it is left
	* unmodified.
	*
	* @param rc
	* configuration to read properties from.
	* @return {@code this}.
	* @since 3.0
	*/
	public WindowCacheConfig fromConfig(Config rc) {
	setPackedGitUseStrongRefs(rc.getBoolean(CONFIG_CORE_SECTION,
	CONFIG_KEY_PACKED_GIT_USE_STRONGREFS,
	isPackedGitUseStrongRefs()));
	setPackedIndexGitUseStrongRefs(rc.getBoolean(CONFIG_CORE_SECTION,
	CONFIG_KEY_PACKED_INDEX_GIT_USE_STRONGREFS, isPackedIndexGitUseStrongRefs()));
	setPackedGitOpenFiles(rc.getInt(CONFIG_CORE_SECTION, null,
	CONFIG_KEY_PACKED_GIT_OPENFILES, getPackedGitOpenFiles()));
	setPackedGitLimit(rc.getLong(CONFIG_CORE_SECTION, null,
	CONFIG_KEY_PACKED_GIT_LIMIT, getPackedGitLimit()));
	setPackedGitWindowSize(rc.getInt(CONFIG_CORE_SECTION, null,
	CONFIG_KEY_PACKED_GIT_WINDOWSIZE, getPackedGitWindowSize()));
	setPackedGitMMAP(rc.getBoolean(CONFIG_CORE_SECTION, null,
	CONFIG_KEY_PACKED_GIT_MMAP, isPackedGitMMAP()));
	setDeltaBaseCacheLimit(rc.getInt(CONFIG_CORE_SECTION, null,
	CONFIG_KEY_DELTA_BASE_CACHE_LIMIT, getDeltaBaseCacheLimit()));

	long maxMem = Runtime.getRuntime().maxMemory();
	long sft = rc.getLong(CONFIG_CORE_SECTION, null,
	CONFIG_KEY_STREAM_FILE_THRESHOLD, getStreamFileThreshold());
	sft = Math.min(sft, maxMem / 4); // don't use more than 1/4 of the heap
	sft = Math.min(sft, Integer.MAX_VALUE); // cannot exceed array length
	setStreamFileThreshold((int) sft);
	return this;
	}

	/**
	* Install this configuration as the live settings.
	* <p>
	* The new configuration is applied immediately. If the new limits are
	* smaller than what is currently cached, older entries will be purged
	* as soon as possible to allow the cache to meet the new limit.
	*
	* @since 3.0
	*/
	@SuppressWarnings("deprecation")
	public void install() {
	WindowCache.reconfigure(this);
	}
	}