freemarker.cache.TemplateCache Maven / Gradle / Ivy
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Google App Engine compliant variation of FreeMarker.
FreeMarker is a "template engine"; a generic tool to generate text output based on templates.
/*
* Copyright (c) 2003 The Visigoth Software Society. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowledgement:
* "This product includes software developed by the
* Visigoth Software Society (http://www.visigoths.org/)."
* Alternately, this acknowledgement may appear in the software itself,
* if and wherever such third-party acknowledgements normally appear.
*
* 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the
* project contributors may be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact [email protected].
*
* 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
* nor may "FreeMarker" or "Visigoth" appear in their names
* without prior written permission of the Visigoth Software Society.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE VISIGOTH SOFTWARE SOCIETY OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Visigoth Software Society. For more
* information on the Visigoth Software Society, please see
* http://www.visigoths.org/
*/
package freemarker.cache;
import java.io.IOException;
import java.io.Reader;
import java.io.Serializable;
import java.io.StringWriter;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import java.util.StringTokenizer;
import freemarker.core.Environment;
import freemarker.log.Logger;
import freemarker.template.Configuration;
import freemarker.template.Template;
import freemarker.template.utility.StringUtil;
import freemarker.template.utility.UndeclaredThrowableException;
/**
* A class that performs caching and on-demand loading of the templates.
* The actual loading is delegated to a {@link TemplateLoader}. Also,
* various constructors provide you with convenient caches with predefined
* behavior. Typically you don't use this class directly - in normal
* circumstances it is hidden behind a {@link Configuration}. However,
* the {@link CacheStorage} it uses can be set with
* {@link freemarker.template.Configuration#setCacheStorage(CacheStorage)}
*
* @author Attila Szegedi
*/
public class TemplateCache
{
private static final String ASTERISKSTR = "*";
private static final String LOCALE_SEPARATOR = "_";
private static final char ASTERISK = '*';
private static final String CURRENT_DIR_PATH_PREFIX = "./";
private static final String CURRENT_DIR_PATH = "/./";
private static final String PARENT_DIR_PATH_PREFIX = "../";
private static final String PARENT_DIR_PATH = "/../";
private static final char SLASH = '/';
private static final Logger logger = Logger.getLogger("freemarker.cache");
private final TemplateLoader mainLoader;
/** DD: [noFallback]
,
fallbackTemplateLoader = new ClassTemplateLoader(TemplateCache.class, "/");
*/
/** Here we keep our cached templates */
private final CacheStorage storage;
private final boolean isStorageConcurrent;
/** The default refresh delay in milliseconds. */
private long delay = 5000;
/** Specifies if localized template lookup is enabled or not */
private boolean localizedLookup = true;
private Configuration config;
/**
* Returns a template cache that will first try to load a template from
* the file system relative to the current user directory (i.e. the value
* of the system property user.dir), then from the classpath.
* This default template cache suits many applications.
*/
public TemplateCache()
{
this(createDefaultTemplateLoader());
}
private static TemplateLoader createDefaultTemplateLoader() {
try {
return new FileTemplateLoader();
} catch(Exception e) {
logger.warn("Could not create a file template loader for current directory", e);
return null;
}
}
/**
* Creates a new template cache with a custom template loader that is used
* to load the templates.
* @param loader the template loader to use.
*/
public TemplateCache(TemplateLoader loader)
{
this(loader, new SoftCacheStorage());
}
/**
* Creates a new template cache with a custom template loader that is used
* to load the templates.
* @param loader the template loader to use.
*/
public TemplateCache(TemplateLoader loader, CacheStorage storage)
{
this.mainLoader = loader;
this.storage = storage;
if(storage == null)
{
throw new IllegalArgumentException("storage == null");
}
isStorageConcurrent = storage instanceof ConcurrentCacheStorage &&
((ConcurrentCacheStorage)storage).isConcurrent();
}
/**
* Sets the configuration object to which this cache belongs. This
* method is called by the configuration itself to establish the
* relation, and should not be called by users.
*/
public void setConfiguration(Configuration config)
{
this.config = config;
clear();
}
public TemplateLoader getTemplateLoader()
{
return mainLoader;
}
public CacheStorage getCacheStorage()
{
return storage;
}
/**
* Loads a template with the given name, in the specified locale and
* using the specified character encoding.
*
* @param name the name of the template. Can't be null. The exact syntax of the name
* is interpreted by the underlying {@link TemplateLoader}, but the
* cache makes some assumptions. First, the name is expected to be
* a hierarchical path, with path components separated by a slash
* character (not with backslash!). The path (the name) must not begin with slash;
* the path is always relative to the "template root directory".
* Then, the .. and . path metaelements will be resolved.
* For example, if the name is a/../b/./c.ftl, then it will be
* simplified to b/c.ftl. The rules regarding this are same as with conventional
* UN*X paths. The path must not reach outside the template root directory, that is,
* it can't be something like "../templates/my.ftl" (not even if the pervious path
* happens to be equivalent with "/my.ftl").
* Further, the path is allowed to contain at most
* one path element whose name is * (asterisk). This path metaelement triggers the
* acquisition mechanism. If the template is not found in
* the location described by the concatenation of the path left to the
* asterisk (called base path) and the part to the right of the asterisk
* (called resource path), the cache will attempt to remove the rightmost
* path component from the base path ("go up one directory") and concatenate
* that with the resource path. The process is repeated until either a
* template is found, or the base path is completely exhausted.
*
* @param locale the requested locale of the template. Can't be null.
* Assuming you have specified en_US as the locale and
* myTemplate.html as the name of the template, the cache will
* first try to retrieve myTemplate_en_US.html, then
* myTemplate.html_en.html, and finally
* myTemplate.html.
*
* @param encoding the character encoding used to interpret the template
* source bytes. Can't be null.
*
* @param parse if true, the loaded template is parsed and interpreted
* as a regular FreeMarker template. If false, the loaded template is
* treated as an unparsed block of text.
*
* @return the loaded template, or null if the template is not found.
*/
public Template getTemplate(String name, Locale locale, String encoding, boolean parse)
throws IOException
{
if (name == null) {
throw new IllegalArgumentException("Argument \"name\" can't be null");
}
if (locale == null) {
throw new IllegalArgumentException("Argument \"locale\" can't be null");
}
if (encoding == null) {
throw new IllegalArgumentException("Argument \"encoding\" can't be null");
}
name = normalizeName(name);
if(name == null) {
return null;
}
Template result = null;
if (mainLoader != null) {
result = getTemplate(mainLoader, name, locale, encoding, parse);
}
/** DD: [noFallback]
if (result == null && name.toLowerCase().endsWith(".ftl")) {
result = getTemplate(fallbackTemplateLoader, name, locale, encoding, parse);
}
*/
return result;
}
private Template getTemplate(TemplateLoader loader, String name, Locale locale, String encoding, boolean parse)
throws IOException
{
boolean debug = logger.isDebugEnabled();
String debugName = debug
? StringUtil.jQuoteNoXSS(name) + "["
+ StringUtil.jQuoteNoXSS(locale) + "," + encoding
+ (parse ? ",parsed] " : ",unparsed] ")
: null;
TemplateKey tk = new TemplateKey(name, locale, encoding, parse);
CachedTemplate cachedTemplate;
if(isStorageConcurrent) {
cachedTemplate = (CachedTemplate)storage.get(tk);
}
else {
synchronized(storage) {
cachedTemplate = (CachedTemplate)storage.get(tk);
}
}
long now = System.currentTimeMillis();
long lastModified = -1L;
Object newlyFoundSource = null;
boolean rethrown = false;
try {
if (cachedTemplate != null) {
// If we're within the refresh delay, return the cached copy
if (now - cachedTemplate.lastChecked < delay) {
if(debug) {
logger.debug(debugName + "cached copy not yet stale; using cached.");
}
// Can be null, indicating a cached negative lookup
Object t = cachedTemplate.templateOrException;
if(t instanceof Template || t == null) {
return (Template)t;
}
else if(t instanceof RuntimeException) {
throwLoadFailedException((RuntimeException)t);
}
else if(t instanceof IOException) {
rethrown = true;
throwLoadFailedException((IOException)t);
}
throw new RuntimeException("t is " + t.getClass().getName());
}
// Clone as the instance bound to the map should be treated as
// immutable to ensure proper concurrent semantics
cachedTemplate = cachedTemplate.cloneCachedTemplate();
// Update the last-checked flag
cachedTemplate.lastChecked = now;
// Find the template source
newlyFoundSource = findTemplateSource(name, locale);
// Template source was removed
if (newlyFoundSource == null) {
if(debug) {
logger.debug(debugName + "no source found.");
}
storeNegativeLookup(tk, cachedTemplate, null);
return null;
}
// If the source didn't change and its last modified date
// also didn't change, return the cached version.
lastModified = loader.getLastModified(newlyFoundSource);
boolean lastModifiedNotChanged = lastModified == cachedTemplate.lastModified;
boolean sourceEquals = newlyFoundSource.equals(cachedTemplate.source);
if(lastModifiedNotChanged && sourceEquals) {
if(debug) {
logger.debug(debugName + "using cached since " +
newlyFoundSource + " didn't change.");
}
storeCached(tk, cachedTemplate);
return (Template)cachedTemplate.templateOrException;
}
else {
if(debug && !sourceEquals) {
logger.debug("Updating source, info for cause: " +
"sourceEquals=" + sourceEquals +
", newlyFoundSource=" + StringUtil.jQuoteNoXSS(newlyFoundSource) +
", cachedTemplate.source=" + StringUtil.jQuoteNoXSS(cachedTemplate.source));
}
if(debug && !lastModifiedNotChanged) {
logger.debug("Updating source, info for cause: " +
"lastModifiedNotChanged=" + lastModifiedNotChanged +
", cache lastModified=" + cachedTemplate.lastModified +
" != file lastModified=" + lastModified);
}
// Update the source
cachedTemplate.source = newlyFoundSource;
}
}
else {
if(debug) {
logger.debug("Could not find template in cache, " +
"creating new one; id=[" +
StringUtil.jQuoteNoXSS(tk.name) + "[" +
StringUtil.jQuoteNoXSS(tk.locale) + "," +
tk.encoding + (tk.parse ? ",parsed] " : ",unparsed] ") +
"]");
}
// Construct a new CachedTemplate entry. Note we set the
// cachedTemplate.lastModified to Long.MIN_VALUE. This is
// a flag that signs it has to be explicitly queried later on.
cachedTemplate = new CachedTemplate();
cachedTemplate.lastChecked = now;
newlyFoundSource = findTemplateSource(name, locale);
if (newlyFoundSource == null) {
storeNegativeLookup(tk, cachedTemplate, null);
return null;
}
cachedTemplate.source = newlyFoundSource;
cachedTemplate.lastModified = lastModified = Long.MIN_VALUE;
}
if(debug) {
logger.debug("Compiling FreeMarker template " +
debugName + " from " + StringUtil.jQuoteNoXSS(newlyFoundSource));
}
// If we get here, then we need to (re)load the template
Object source = cachedTemplate.source;
Template t = loadTemplate(loader, name, locale, encoding, parse, source);
cachedTemplate.templateOrException = t;
cachedTemplate.lastModified =
lastModified == Long.MIN_VALUE
? loader.getLastModified(source)
: lastModified;
storeCached(tk, cachedTemplate);
return t;
}
catch(RuntimeException e) {
storeNegativeLookup(tk, cachedTemplate, e);
throw e;
}
catch(IOException e) {
if(!rethrown) {
storeNegativeLookup(tk, cachedTemplate, e);
}
throw e;
}
finally {
if(newlyFoundSource != null) {
loader.closeTemplateSource(newlyFoundSource);
}
}
}
private static final Method INIT_CAUSE = getInitCauseMethod();
private static final Method getInitCauseMethod() {
try {
return Throwable.class.getMethod("initCause", new Class[] { Throwable.class });
} catch(NoSuchMethodException e) {
return null;
}
}
private void throwLoadFailedException(Exception e) throws IOException {
IOException ioe;
if(INIT_CAUSE != null) {
ioe = new IOException("There was an error loading the " +
"template on an earlier attempt; it is attached as a cause");
try {
INIT_CAUSE.invoke(ioe, new Object[] { e });
} catch(RuntimeException ex) {
throw ex;
} catch(Exception ex) {
throw new UndeclaredThrowableException(ex);
}
}
else {
ioe = new IOException("There was an error loading the " +
"template on an earlier attempt: " + e.getClass().getName() +
": " + e.getMessage());
}
throw ioe;
}
private void storeNegativeLookup(TemplateKey tk,
CachedTemplate cachedTemplate, Exception e) {
cachedTemplate.templateOrException = e;
cachedTemplate.source = null;
cachedTemplate.lastModified = 0L;
storeCached(tk, cachedTemplate);
}
private void storeCached(TemplateKey tk, CachedTemplate cachedTemplate) {
if(isStorageConcurrent) {
storage.put(tk, cachedTemplate);
}
else {
synchronized(storage) {
storage.put(tk, cachedTemplate);
}
}
}
private Template loadTemplate(TemplateLoader loader, String name, Locale locale, String encoding,
boolean parse, Object source)
throws IOException
{
Template template;
Reader reader = loader.getReader(source, encoding);
try
{
if(parse)
{
try {
template = new Template(name, reader, config, encoding);
}
catch (Template.WrongEncodingException wee) {
encoding = wee.specifiedEncoding;
reader = loader.getReader(source, encoding);
template = new Template(name, reader, config, encoding);
}
template.setLocale(locale);
}
else
{
// Read the contents into a StringWriter, then construct a single-textblock
// template from it.
StringWriter sw = new StringWriter();
char[] buf = new char[4096];
for(;;)
{
int charsRead = reader.read(buf);
if (charsRead > 0)
{
sw.write(buf, 0, charsRead);
}
else if(charsRead == -1)
{
break;
}
}
template = Template.getPlainTextTemplate(name, sw.toString(), config);
template.setLocale(locale);
}
template.setEncoding(encoding);
}
finally
{
reader.close();
}
return template;
}
/**
* Gets the delay in milliseconds between checking for newer versions of a
* template source.
* @return the current value of the delay
*/
public synchronized long getDelay()
{
return delay;
}
/**
* Sets the delay in milliseconds between checking for newer versions of a
* template sources.
* @param delay the new value of the delay
*/
public synchronized void setDelay(long delay)
{
this.delay = delay;
}
/**
* Returns if localized template lookup is enabled or not.
*/
public synchronized boolean getLocalizedLookup()
{
return localizedLookup;
}
/**
* Setis if localized template lookup is enabled or not.
*/
public synchronized void setLocalizedLookup(boolean localizedLookup)
{
this.localizedLookup = localizedLookup;
}
/**
* Removes all entries from the cache, forcing reloading of templates
* on subsequent {@link #getTemplate(String, Locale, String, boolean)}
* calls. If the configured template loader is
* {@link StatefulTemplateLoader stateful}, then its
* {@link StatefulTemplateLoader#resetState()} method is invoked as well.
*/
public void clear()
{
synchronized (storage) {
storage.clear();
if(mainLoader instanceof StatefulTemplateLoader) {
((StatefulTemplateLoader)mainLoader).resetState();
}
}
}
public static String getFullTemplatePath(Environment env, String parentTemplateDir, String templateNameString)
{
if (!env.isClassicCompatible()) {
if (templateNameString.indexOf("://") >0) {
;
}
else if (templateNameString.length() > 0 && templateNameString.charAt(0) == '/') {
int protIndex = parentTemplateDir.indexOf("://");
if (protIndex >0) {
templateNameString = parentTemplateDir.substring(0, protIndex + 2) + templateNameString;
} else {
templateNameString = templateNameString.substring(1);
}
}
else {
templateNameString = parentTemplateDir + templateNameString;
}
}
return templateNameString;
}
private Object findTemplateSource(String name, Locale locale)
throws
IOException
{
if (localizedLookup) {
int lastDot = name.lastIndexOf('.');
String prefix = lastDot == -1 ? name : name.substring(0, lastDot);
String suffix = lastDot == -1 ? "" : name.substring(lastDot);
String localeName = LOCALE_SEPARATOR + locale.toString();
StringBuffer buf = new StringBuffer(name.length() + localeName.length());
buf.append(prefix);
for (;;)
{
buf.setLength(prefix.length());
String path = buf.append(localeName).append(suffix).toString();
Object templateSource = acquireTemplateSource(path);
if (templateSource != null)
{
return templateSource;
}
int lastUnderscore = localeName.lastIndexOf('_');
if (lastUnderscore == -1)
break;
localeName = localeName.substring(0, lastUnderscore);
}
return null;
}
else
{
return acquireTemplateSource(name);
}
}
private Object acquireTemplateSource(String path) throws IOException
{
int asterisk = path.indexOf(ASTERISK);
// Shortcut in case there is no acquisition
if(asterisk == -1)
{
return mainLoader.findTemplateSource(path);
}
StringTokenizer tok = new StringTokenizer(path, "/");
int lastAsterisk = -1;
List tokpath = new ArrayList();
while(tok.hasMoreTokens())
{
String pathToken = tok.nextToken();
if(pathToken.equals(ASTERISKSTR))
{
if(lastAsterisk != -1)
{
tokpath.remove(lastAsterisk);
}
lastAsterisk = tokpath.size();
}
tokpath.add(pathToken);
}
String basePath = concatPath(tokpath, 0, lastAsterisk);
String resourcePath = concatPath(tokpath, lastAsterisk + 1, tokpath.size());
if(resourcePath.endsWith("/"))
{
resourcePath = resourcePath.substring(0, resourcePath.length() - 1);
}
StringBuffer buf = new StringBuffer(path.length()).append(basePath);
int l = basePath.length();
boolean debug = logger.isDebugEnabled();
for(;;)
{
String fullPath = buf.append(resourcePath).toString();
if(debug)
{
logger.debug("Trying to find template source "
+ StringUtil.jQuoteNoXSS(fullPath));
}
Object templateSource = mainLoader.findTemplateSource(fullPath);
if(templateSource != null)
{
return templateSource;
}
if(l == 0)
{
return null;
}
l = basePath.lastIndexOf(SLASH, l - 2) + 1;
buf.setLength(l);
}
}
private String concatPath(List path, int from, int to)
{
StringBuffer buf = new StringBuffer((to - from) * 16);
for(int i = from; i < to; ++i)
{
buf.append(path.get(i)).append('/');
}
return buf.toString();
}
private static String normalizeName(String name) {
int cppIdx = name.indexOf("://");
if (cppIdx > 0) {
int zIdx = name.indexOf(0);
if (zIdx != -1 && zIdx < cppIdx) return null;
return name;
}
for(;;) {
int parentDirPathLoc = name.indexOf(PARENT_DIR_PATH);
if(parentDirPathLoc == 0) {
// If it starts with /../, then it reaches outside the template
// root.
return null;
}
if(parentDirPathLoc == -1) {
if(name.startsWith(PARENT_DIR_PATH_PREFIX)) {
// Another attempt to reach out of template root.
return null;
}
break;
}
int previousSlashLoc = name.lastIndexOf(SLASH, parentDirPathLoc - 1);
name = name.substring(0, previousSlashLoc + 1) +
name.substring(parentDirPathLoc + PARENT_DIR_PATH.length());
}
for(;;) {
int currentDirPathLoc = name.indexOf(CURRENT_DIR_PATH);
if(currentDirPathLoc == -1) {
if(name.startsWith(CURRENT_DIR_PATH_PREFIX)) {
name = name.substring(CURRENT_DIR_PATH_PREFIX.length());
}
break;
}
name = name.substring(0, currentDirPathLoc) +
name.substring(currentDirPathLoc + CURRENT_DIR_PATH.length() - 1);
}
// Editing can leave us with a leading slash; strip it.
if(name.length() > 1 && name.charAt(0) == SLASH) {
name = name.substring(1);
}
return name;
}
/**
* This class holds a (name, locale) pair and is used as the key in
* the cached templates map.
*/
private static final class TemplateKey
{
private final String name;
private final Locale locale;
private final String encoding;
private final boolean parse;
TemplateKey(String name, Locale locale, String encoding, boolean parse)
{
this.name = name;
this.locale = locale;
this.encoding = encoding;
this.parse = parse;
}
public boolean equals(Object o)
{
if (o instanceof TemplateKey)
{
TemplateKey tk = (TemplateKey)o;
return
parse == tk.parse &&
name.equals(tk.name) &&
locale.equals(tk.locale) &&
encoding.equals(tk.encoding);
}
return false;
}
public int hashCode()
{
return
name.hashCode() ^
locale.hashCode() ^
encoding.hashCode() ^
(parse ? Boolean.FALSE : Boolean.TRUE).hashCode();
}
}
/**
* This class holds the cached template and associated information
* (the source object, and the last-checked and last-modified timestamps).
* It is used as the value in the cached templates map. Note: this class
* is Serializable to allow custom 3rd party CacheStorage implementations
* to serialize/replicate them (see tracker issue #1926150); FreeMarker
* code itself doesn't rely on its serializability.
*/
private static final class CachedTemplate implements Cloneable, Serializable
{
private static final long serialVersionUID = 1L;
Object templateOrException;
Object source;
long lastChecked;
long lastModified;
public CachedTemplate cloneCachedTemplate() {
try {
return (CachedTemplate)super.clone();
}
catch(CloneNotSupportedException e) {
throw new UndeclaredThrowableException(e);
}
}
}
}