<?php
-/**
- *
- * @package MediaWiki
- */
/**
- * Pure virtual parent
- * @package MediaWiki
+ * Base class for general text storage via the "object" flag in old_flags, or
+ * two-part external storage URLs. Used for represent efficient concatenated
+ * storage, and migration-related pointer objects.
*/
-class HistoryBlob
+interface HistoryBlob
{
- /**
- * setMeta and getMeta currently aren't used for anything, I just thought
- * they might be useful in the future.
- * @param $meta String: a single string.
- */
- function setMeta( $meta ) {}
-
- /**
- * setMeta and getMeta currently aren't used for anything, I just thought
- * they might be useful in the future.
- * Gets the meta-value
- */
- function getMeta() {}
-
/**
* Adds an item of text, returns a stub object which points to the item.
* You must call setLocation() on the stub object before storing it to the
* database
+ * Returns the key for getItem()
*/
- function addItem() {}
+ public function addItem( $text );
/**
- * Get item by hash
+ * Get item by key, or false if the key is not present
*/
- function getItem( $hash ) {}
+ public function getItem( $key );
- # Set the "default text"
- # This concept is an odd property of the current DB schema, whereby each text item has a revision
- # associated with it. The default text is the text of the associated revision. There may, however,
- # be other revisions in the same object
- function setText() {}
+ /**
+ * Set the "default text"
+ * This concept is an odd property of the current DB schema, whereby each text item has a revision
+ * associated with it. The default text is the text of the associated revision. There may, however,
+ * be other revisions in the same object.
+ *
+ * Default text is not required for two-part external storage URLs.
+ */
+ public function setText( $text );
/**
* Get default text. This is called from Revision::getRevisionText()
*/
- function getText() {}
+ function getText();
}
/**
- * The real object
- * @package MediaWiki
+ * Concatenated gzip (CGZ) storage
+ * Improves compression ratio by concatenating like objects before gzipping
*/
-class ConcatenatedGzipHistoryBlob extends HistoryBlob
+class ConcatenatedGzipHistoryBlob implements HistoryBlob
{
- /* private */ var $mVersion = 0, $mCompressed = false, $mItems = array(), $mDefaultHash = '';
- /* private */ var $mFast = 0, $mSize = 0;
+ public $mVersion = 0, $mCompressed = false, $mItems = array(), $mDefaultHash = '';
+ public $mFast = 0, $mSize = 0;
- function ConcatenatedGzipHistoryBlob() {
+ /** Constructor */
+ public function ConcatenatedGzipHistoryBlob() {
if ( !function_exists( 'gzdeflate' ) ) {
throw new MWException( "Need zlib support to read or write this kind of history object (ConcatenatedGzipHistoryBlob)\n" );
}
}
- /** @todo document */
- function setMeta( $metaData ) {
- $this->uncompress();
- $this->mItems['meta'] = $metaData;
- }
-
- /** @todo document */
- function getMeta() {
- $this->uncompress();
- return $this->mItems['meta'];
- }
-
- /** @todo document */
- function addItem( $text ) {
+ public function addItem( $text ) {
$this->uncompress();
$hash = md5( $text );
$this->mItems[$hash] = $text;
$this->mSize += strlen( $text );
- $stub = new HistoryBlobStub( $hash );
- return $stub;
+ return $hash;
}
- /** @todo document */
- function getItem( $hash ) {
+ public function getItem( $hash ) {
$this->uncompress();
if ( array_key_exists( $hash, $this->mItems ) ) {
return $this->mItems[$hash];
}
}
- /** @todo document */
- function removeItem( $hash ) {
+ public function setText( $text ) {
+ $this->uncompress();
+ $this->mDefaultHash = $this->addItem( $text );
+ }
+
+ public function getText() {
+ $this->uncompress();
+ return $this->getItem( $this->mDefaultHash );
+ }
+
+ /**
+ * Remove an item
+ */
+ public function removeItem( $hash ) {
$this->mSize -= strlen( $this->mItems[$hash] );
unset( $this->mItems[$hash] );
}
- /** @todo document */
- function compress() {
+ /**
+ * Compress the bulk data in the object
+ */
+ public function compress() {
if ( !$this->mCompressed ) {
$this->mItems = gzdeflate( serialize( $this->mItems ) );
$this->mCompressed = true;
}
}
- /** @todo document */
- function uncompress() {
+ /**
+ * Uncompress bulk data
+ */
+ public function uncompress() {
if ( $this->mCompressed ) {
$this->mItems = unserialize( gzinflate( $this->mItems ) );
$this->mCompressed = false;
}
}
- /** @todo document */
- function getText() {
- $this->uncompress();
- return $this->getItem( $this->mDefaultHash );
- }
- /** @todo document */
- function setText( $text ) {
- $this->uncompress();
- $stub = $this->addItem( $text );
- $this->mDefaultHash = $stub->mHash;
- }
-
- /** @todo document */
function __sleep() {
$this->compress();
return array( 'mVersion', 'mCompressed', 'mItems', 'mDefaultHash' );
}
- /** @todo document */
function __wakeup() {
$this->uncompress();
}
/**
- * Determines if this object is happy
+ * Helper function for compression jobs
+ * Returns true until the object is "full" and ready to be committed
*/
- function isHappy( $maxFactor, $factorThreshold ) {
+ public function isHappy( $maxFactor, $factorThreshold ) {
if ( count( $this->mItems ) == 0 ) {
return true;
}
/**
- * @package MediaWiki
+ * Pointer object for an item within a CGZ blob stored in the text table.
*/
class HistoryBlobStub {
var $mOldId, $mHash, $mRef;
- /** @todo document */
+ /**
+ * @param string $hash The content hash of the text
+ * @param integer $oldid The old_id for the CGZ object
+ */
function HistoryBlobStub( $hash = '', $oldid = 0 ) {
$this->mHash = $hash;
}
$this->mOldId = $id;
}
- /**
- * Sets the location (old_id) of the referring object
- */
+ /**
+ * Sets the location (old_id) of the referring object
+ */
function setReferrer( $id ) {
$this->mRef = $id;
}
- /**
- * Gets the location of the referring object
- */
+ /**
+ * Gets the location of the referring object
+ */
function getReferrer() {
return $this->mRef;
}
- /** @todo document */
function getText() {
- $fname = 'HistoryBlob::getText';
+ $fname = 'HistoryBlobStub::getText';
global $wgBlobCache;
if( isset( $wgBlobCache[$this->mOldId] ) ) {
$obj = $wgBlobCache[$this->mOldId];
} else {
- $dbr =& wfGetDB( DB_SLAVE );
+ $dbr = wfGetDB( DB_SLAVE );
$row = $dbr->selectRow( 'text', array( 'old_flags', 'old_text' ), array( 'old_id' => $this->mOldId ) );
if( !$row ) {
return false;
return $obj->getItem( $this->mHash );
}
- /** @todo document */
+ /**
+ * Get the content hash
+ */
function getHash() {
return $this->mHash;
}
*
* Serialized HistoryBlobCurStub objects will be inserted into the text table
* on conversion if $wgFastSchemaUpgrades is set to true.
- *
- * @package MediaWiki
*/
class HistoryBlobCurStub {
var $mCurId;
- /** @todo document */
+ /**
+ * @param integer $curid The cur_id pointed to
+ */
function HistoryBlobCurStub( $curid = 0 ) {
$this->mCurId = $curid;
}
$this->mCurId = $id;
}
- /** @todo document */
function getText() {
- $dbr =& wfGetDB( DB_SLAVE );
+ $dbr = wfGetDB( DB_SLAVE );
$row = $dbr->selectRow( 'cur', array( 'cur_text' ), array( 'cur_id' => $this->mCurId ) );
if( !$row ) {
return false;
}
}
+/**
+ * Diff-based history compression
+ * Requires xdiff 1.5+ and zlib
+ */
+class DiffHistoryBlob implements HistoryBlob {
+ /** Uncompressed item cache */
+ var $mItems = array();
+
+ /**
+ * Array of diffs, where $this->mDiffs[0] is the diff between
+ * $this->mDiffs[0] and $this->mDiffs[1]
+ */
+ var $mDiffs = array();
+
+ /**
+ * The key for getText()
+ */
+ var $mDefaultKey;
+
+ /**
+ * Compressed storage
+ */
+ var $mCompressed;
+
+ /**
+ * True if the object is locked against further writes
+ */
+ var $mFrozen = false;
+
+
+ function __construct() {
+ if ( !function_exists( 'xdiff_string_bdiff' ) ){
+ throw new MWException( "Need xdiff 1.5+ support to read or write DiffHistoryBlob\n" );
+ }
+ if ( !function_exists( 'gzdeflate' ) ) {
+ throw new MWException( "Need zlib support to read or write DiffHistoryBlob\n" );
+ }
+ }
+
+ function addItem( $text ) {
+ if ( $this->mFrozen ) {
+ throw new MWException( __METHOD__.": Cannot add more items after sleep/wakeup" );
+ }
+
+ $this->mItems[] = $text;
+ $i = count( $this->mItems ) - 1;
+ if ( $i > 0 ) {
+ # Need to do a null concatenation with warnings off, due to bugs in the current version of xdiff
+ # "String is not zero-terminated"
+ wfSuppressWarnings();
+ $this->mDiffs[] = xdiff_string_bdiff( $this->mItems[$i-1], $text ) . '';
+ wfRestoreWarnings();
+ }
+ return $i;
+ }
-?>
+ function getItem( $key ) {
+ if ( $key > count( $this->mDiffs ) + 1 ) {
+ return false;
+ }
+ $key = intval( $key );
+ if ( $key == 0 ) {
+ return $this->mItems[0];
+ }
+
+ $last = count( $this->mItems ) - 1;
+ for ( $i = $last + 1; $i <= $key; $i++ ) {
+ # Need to do a null concatenation with warnings off, due to bugs in the current version of xdiff
+ # "String is not zero-terminated"
+ wfSuppressWarnings();
+ $this->mItems[$i] = xdiff_string_bpatch( $this->mItems[$i - 1], $this->mDiffs[$i - 1] ) . '';
+ wfRestoreWarnings();
+ }
+ return $this->mItems[$key];
+ }
+
+ function setText( $text ) {
+ $this->mDefaultKey = $this->addItem( $text );
+ }
+
+ function getText() {
+ return $this->getItem( $this->mDefaultKey );
+ }
+
+ function __sleep() {
+ if ( !isset( $this->mItems[0] ) ) {
+ // Empty object
+ $info = false;
+ } else {
+ $info = array(
+ 'base' => $this->mItems[0],
+ 'diffs' => $this->mDiffs
+ );
+ }
+ if ( isset( $this->mDefaultKey ) ) {
+ $info['default'] = $this->mDefaultKey;
+ }
+ $this->mCompressed = gzdeflate( serialize( $info ) );
+ return array( 'mCompressed' );
+ }
+
+ function __wakeup() {
+ // addItem() doesn't work if mItems is partially filled from mDiffs
+ $this->mFrozen = true;
+ $info = unserialize( gzinflate( $this->mCompressed ) );
+ unset( $this->mCompressed );
+
+ if ( !$info ) {
+ // Empty object
+ return;
+ }
+
+ if ( isset( $info['default'] ) ) {
+ $this->mDefaultKey = $info['default'];
+ }
+ $this->mItems[0] = $info['base'];
+ $this->mDiffs = $info['diffs'];
+ }
+}
dépôts / lhc / web / wiklou.git / blobdiff