diff options
Diffstat (limited to 'includes/HistoryBlob.php')
| -rw-r--r-- | includes/HistoryBlob.php | 308 |
1 files changed, 308 insertions, 0 deletions
diff --git a/includes/HistoryBlob.php b/includes/HistoryBlob.php new file mode 100644 index 00000000..8f5d3624 --- /dev/null +++ b/includes/HistoryBlob.php @@ -0,0 +1,308 @@ +<?php +/** + * + * @package MediaWiki + */ + +/** + * Pure virtual parent + * @package MediaWiki + */ +class 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 + */ + function addItem() {} + + /** + * Get item by hash + */ + function getItem( $hash ) {} + + # 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() {} + + /** + * Get default text. This is called from Revision::getRevisionText() + */ + function getText() {} +} + +/** + * The real object + * @package MediaWiki + */ +class ConcatenatedGzipHistoryBlob extends HistoryBlob +{ + /* private */ var $mVersion = 0, $mCompressed = false, $mItems = array(), $mDefaultHash = ''; + /* private */ var $mFast = 0, $mSize = 0; + + 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 ) { + $this->uncompress(); + $hash = md5( $text ); + $this->mItems[$hash] = $text; + $this->mSize += strlen( $text ); + + $stub = new HistoryBlobStub( $hash ); + return $stub; + } + + /** @todo document */ + function getItem( $hash ) { + $this->uncompress(); + if ( array_key_exists( $hash, $this->mItems ) ) { + return $this->mItems[$hash]; + } else { + return false; + } + } + + /** @todo document */ + function removeItem( $hash ) { + $this->mSize -= strlen( $this->mItems[$hash] ); + unset( $this->mItems[$hash] ); + } + + /** @todo document */ + function compress() { + if ( !$this->mCompressed ) { + $this->mItems = gzdeflate( serialize( $this->mItems ) ); + $this->mCompressed = true; + } + } + + /** @todo document */ + 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 + */ + function isHappy( $maxFactor, $factorThreshold ) { + if ( count( $this->mItems ) == 0 ) { + return true; + } + if ( !$this->mFast ) { + $this->uncompress(); + $record = serialize( $this->mItems ); + $size = strlen( $record ); + $avgUncompressed = $size / count( $this->mItems ); + $compressed = strlen( gzdeflate( $record ) ); + + if ( $compressed < $factorThreshold * 1024 ) { + return true; + } else { + return $avgUncompressed * $maxFactor < $compressed; + } + } else { + return count( $this->mItems ) <= 10; + } + } +} + + +/** + * One-step cache variable to hold base blobs; operations that + * pull multiple revisions may often pull multiple times from + * the same blob. By keeping the last-used one open, we avoid + * redundant unserialization and decompression overhead. + */ +global $wgBlobCache; +$wgBlobCache = array(); + + +/** + * @package MediaWiki + */ +class HistoryBlobStub { + var $mOldId, $mHash, $mRef; + + /** @todo document */ + function HistoryBlobStub( $hash = '', $oldid = 0 ) { + $this->mHash = $hash; + } + + /** + * Sets the location (old_id) of the main object to which this object + * points + */ + function setLocation( $id ) { + $this->mOldId = $id; + } + + /** + * Sets the location (old_id) of the referring object + */ + function setReferrer( $id ) { + $this->mRef = $id; + } + + /** + * Gets the location of the referring object + */ + function getReferrer() { + return $this->mRef; + } + + /** @todo document */ + function getText() { + $fname = 'HistoryBlob::getText'; + global $wgBlobCache; + if( isset( $wgBlobCache[$this->mOldId] ) ) { + $obj = $wgBlobCache[$this->mOldId]; + } else { + $dbr =& wfGetDB( DB_SLAVE ); + $row = $dbr->selectRow( 'text', array( 'old_flags', 'old_text' ), array( 'old_id' => $this->mOldId ) ); + if( !$row ) { + return false; + } + $flags = explode( ',', $row->old_flags ); + if( in_array( 'external', $flags ) ) { + $url=$row->old_text; + @list($proto,$path)=explode('://',$url,2); + if ($path=="") { + wfProfileOut( $fname ); + return false; + } + require_once('ExternalStore.php'); + $row->old_text=ExternalStore::fetchFromUrl($url); + + } + if( !in_array( 'object', $flags ) ) { + return false; + } + + if( in_array( 'gzip', $flags ) ) { + // This shouldn't happen, but a bug in the compress script + // may at times gzip-compress a HistoryBlob object row. + $obj = unserialize( gzinflate( $row->old_text ) ); + } else { + $obj = unserialize( $row->old_text ); + } + + if( !is_object( $obj ) ) { + // Correct for old double-serialization bug. + $obj = unserialize( $obj ); + } + + // Save this item for reference; if pulling many + // items in a row we'll likely use it again. + $obj->uncompress(); + $wgBlobCache = array( $this->mOldId => $obj ); + } + return $obj->getItem( $this->mHash ); + } + + /** @todo document */ + function getHash() { + return $this->mHash; + } +} + + +/** + * To speed up conversion from 1.4 to 1.5 schema, text rows can refer to the + * leftover cur table as the backend. This avoids expensively copying hundreds + * of megabytes of data during the conversion downtime. + * + * 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 */ + function HistoryBlobCurStub( $curid = 0 ) { + $this->mCurId = $curid; + } + + /** + * Sets the location (cur_id) of the main object to which this object + * points + */ + function setLocation( $id ) { + $this->mCurId = $id; + } + + /** @todo document */ + function getText() { + $dbr =& wfGetDB( DB_SLAVE ); + $row = $dbr->selectRow( 'cur', array( 'cur_text' ), array( 'cur_id' => $this->mCurId ) ); + if( !$row ) { + return false; + } + return $row->cur_text; + } +} + + +?> |