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Tidy up CacheManager comments and documentation

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Change-Id: I3a7d3836a51ef3092652ade87f29bc84af69ee7d
This commit is contained in:
Steve Block
2011-01-04 14:24:05 +00:00
parent e7fc1d26c5
commit 67ba204aa2
1 changed files with 54 additions and 50 deletions
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104
core/java/android/webkit/CacheManager.java
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@@ -183,8 +183,10 @@ public final class CacheManager {
}
/**
* initialize the CacheManager. WebView should handle this for each process.
*
* Initialize the CacheManager.
*
* Note that this is called automatically when a {@link android.webkit.WebView} is created.
*
* @param context The application context.
*/
static void init(Context context) {
@@ -195,10 +197,10 @@ public final class CacheManager {
mClearCacheOnInit = false;
}
}
/**
* Create the cache directory if it does not already exist.
*
*
* @return true if the cache directory didn't exist and was created.
*/
static private boolean createCacheDirectory() {
@@ -211,7 +213,7 @@ public final class CacheManager {
mBaseDir.toString(),
FileUtils.S_IRWXU | FileUtils.S_IRWXG,
-1, -1);
// If we did create the directory, we need to flush
// If we did create the directory, we need to flush
// the cache database. The directory could be recreated
// because the system flushed all the data/cache directories
// to free up disk space.
@@ -224,8 +226,9 @@ public final class CacheManager {
}
/**
* get the base directory of the cache. With localPath of the CacheResult,
* it identifies the cache file.
* Get the base directory of the cache. Together with the local path of the CacheResult,
* obtained from {@link android.webkit.CacheManager.CacheResult#getLocalPath}, this
* identifies the cache file.
*
* @return File The base directory of the cache.
*
@@ -237,9 +240,9 @@ public final class CacheManager {
}
/**
* set the flag to control whether cache is enabled or disabled
*
* @param disabled true to disable the cache
* Sets whether the cache is disabled.
*
* @param disabled Whether the cache should be disabled
*/
static void setCacheDisabled(boolean disabled) {
if (disabled == mDisabled) {
@@ -252,9 +255,9 @@ public final class CacheManager {
}
/**
* get the state of the current cache, enabled or disabled
* Whether the cache is disabled.
*
* @return return if it is disabled
* @return return Whether the cache is disabled
*
* @deprecated Access to the HTTP cache will be removed in a future release.
*/
@@ -321,12 +324,14 @@ public final class CacheManager {
}
/**
* Given a url, returns the CacheResult if exists. Otherwise returns null.
* If headers are provided and a cache needs validation,
* HEADER_KEY_IFNONEMATCH or HEADER_KEY_IFMODIFIEDSINCE will be set in the
* cached headers.
*
* @return the CacheResult for a given url.
* Given a URL, returns the corresponding CacheResult if it exists, or null otherwise.
*
* The output stream of the CacheEntry object is initialized and opened and should be closed by
* the caller when access to the undelying file is no longer required.
* If a non-zero value is provided for the headers map, and the cache entry needs validation,
* HEADER_KEY_IFNONEMATCH or HEADER_KEY_IFMODIFIEDSINCE will be set in headers.
*
* @return The CacheResult for the given URL
*
* @deprecated Access to the HTTP cache will be removed in a future release.
*/
@@ -345,40 +350,39 @@ public final class CacheManager {
String databaseKey = getDatabaseKey(url, postIdentifier);
CacheResult result = mDataBase.getCache(databaseKey);
if (result != null) {
if (result.contentLength == 0) {
if (!checkCacheRedirect(result.httpStatusCode)) {
// this should not happen. If it does, remove it.
mDataBase.removeCache(databaseKey);
return null;
}
} else {
File src = new File(mBaseDir, result.localPath);
try {
// open here so that even the file is deleted, the content
// is still readable by the caller until close() is called
result.inStream = new FileInputStream(src);
} catch (FileNotFoundException e) {
// the files in the cache directory can be removed by the
// system. If it is gone, clean up the database
mDataBase.removeCache(databaseKey);
return null;
}
}
} else {
if (result == null) {
return null;
}
if (result.contentLength == 0) {
if (!isCachableRedirect(result.httpStatusCode)) {
// This should not happen. If it does, remove it.
mDataBase.removeCache(databaseKey);
return null;
}
} else {
File src = new File(mBaseDir, result.localPath);
try {
// Open the file here so that even if it is deleted, the content
// is still readable by the caller until close() is called.
result.inStream = new FileInputStream(src);
} catch (FileNotFoundException e) {
// The files in the cache directory can be removed by the
// system. If it is gone, clean up the database.
mDataBase.removeCache(databaseKey);
return null;
}
}
// null headers request coming from CACHE_MODE_CACHE_ONLY
// which implies that it needs cache even it is expired.
// negative expires means time in the far future.
// A null value for headers is used by CACHE_MODE_CACHE_ONLY to imply
// that we should provide the cache result even if it is expired.
// Note that a negative expires value means a time in the far future.
if (headers != null && result.expires >= 0
&& result.expires <= System.currentTimeMillis()) {
if (result.lastModified == null && result.etag == null) {
return null;
}
// return HEADER_KEY_IFNONEMATCH or HEADER_KEY_IFMODIFIEDSINCE
// for requesting validation
// Return HEADER_KEY_IFNONEMATCH or HEADER_KEY_IFMODIFIEDSINCE
// for requesting validation.
if (result.etag != null) {
headers.put(HEADER_KEY_IFNONEMATCH, result.etag);
}
@@ -433,7 +437,7 @@ public final class CacheManager {
// like the other browsers, do not cache redirects containing a cookie
// header.
if (checkCacheRedirect(statusCode) && !headers.getSetCookie().isEmpty()) {
if (isCachableRedirect(statusCode) && !headers.getSetCookie().isEmpty()) {
// remove the saved cache if there is any
mDataBase.removeCache(databaseKey);
return null;
@@ -494,7 +498,7 @@ public final class CacheManager {
return;
}
boolean redirect = checkCacheRedirect(cacheRet.httpStatusCode);
boolean redirect = isCachableRedirect(cacheRet.httpStatusCode);
if (redirect) {
// location is in database, no need to keep the file
cacheRet.contentLength = 0;
@@ -525,9 +529,9 @@ public final class CacheManager {
}
/**
* remove all cache files
*
* @return true if it succeeds
* Remove all cache files.
*
* @return Whether the removal succeeded.
*/
static boolean removeAllCacheFiles() {
// Note, this is called before init() when the database is
@@ -603,7 +607,7 @@ public final class CacheManager {
mDataBase.clearCache();
}
private static boolean checkCacheRedirect(int statusCode) {
private static boolean isCachableRedirect(int statusCode) {
if (statusCode == 301 || statusCode == 302 || statusCode == 307) {
// as 303 can't be cached, we do not return true
return true;