<?php
-/**
- *
- * @package MediaWiki
- */
/**
* Pure virtual parent
- * @package MediaWiki
+ * @todo document (needs a one-sentence top-level class description, that answers the question: "what is a HistoryBlob?")
*/
-class HistoryBlob
+interface HistoryBlob
{
- function setMeta() {}
- function getMeta() {}
- function addItem() {}
- function getItem() {}
+ /**
+ * 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.
+ */
+ public 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
+ */
+ public 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
+ */
+ public function addItem( $text );
+
+ /**
+ * Get item by hash
+ */
+ public 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
+ public function setText( $text );
+
+ /**
+ * Get default text. This is called from Revision::getRevisionText()
+ */
+ function getText();
}
/**
* The real object
- * @package MediaWiki
+ * @todo document (needs one-sentence top-level class description + function descriptions).
*/
-class ConcatenatedGzipHistoryBlob
+class ConcatenatedGzipHistoryBlob implements HistoryBlob
{
- /* private */ var $mVersion = 0, $mCompressed = false, $mItems = array();
+ public $mVersion = 0, $mCompressed = false, $mItems = array(), $mDefaultHash = '';
+ public $mFast = 0, $mSize = 0;
- function HistoryBlob() {
+ /** Constructor */
+ public function ConcatenatedGzipHistoryBlob() {
if ( !function_exists( 'gzdeflate' ) ) {
- die( "Need zlib support to read or write this kind of history object (ConcatenatedGzipHistoryBlob)\n" );
+ throw new MWException( "Need zlib support to read or write this kind of history object (ConcatenatedGzipHistoryBlob)\n" );
}
}
-
- function setMeta( $metaData ) {
+
+ #
+ # HistoryBlob implementation:
+ #
+
+ /** @todo document */
+ public function setMeta( $metaData ) {
$this->uncompress();
$this->mItems['meta'] = $metaData;
}
- function getMeta() {
+ /** @todo document */
+ public function getMeta() {
$this->uncompress();
return $this->mItems['meta'];
}
-
- function addItem( $text ) {
+
+ /** @todo document */
+ public function addItem( $text ) {
$this->uncompress();
- $this->mItems[md5($text)] = $text;
+ $hash = md5( $text );
+ $this->mItems[$hash] = $text;
+ $this->mSize += strlen( $text );
+
+ $stub = new HistoryBlobStub( $hash );
+ return $stub;
}
- function getItem( $hash ) {
- $this->compress();
- return $this->mItems[$hash];
+ /** @todo document */
+ public function getItem( $hash ) {
+ $this->uncompress();
+ if ( array_key_exists( $hash, $this->mItems ) ) {
+ return $this->mItems[$hash];
+ } else {
+ return false;
+ }
+ }
+
+ /** @todo document */
+ public function setText( $text ) {
+ $this->uncompress();
+ $stub = $this->addItem( $text );
+ $this->mDefaultHash = $stub->mHash;
}
- function compress() {
+ /** @todo document */
+ public function getText() {
+ $this->uncompress();
+ return $this->getItem( $this->mDefaultHash );
+ }
+
+ # HistoryBlob implemented.
+
+
+ /** @todo document */
+ public function removeItem( $hash ) {
+ $this->mSize -= strlen( $this->mItems[$hash] );
+ unset( $this->mItems[$hash] );
+ }
+
+ /** @todo document */
+ public function compress() {
if ( !$this->mCompressed ) {
$this->mItems = gzdeflate( serialize( $this->mItems ) );
$this->mCompressed = true;
}
}
- function uncompress() {
+ /** @todo document */
+ public function uncompress() {
if ( $this->mCompressed ) {
$this->mItems = unserialize( gzinflate( $this->mItems ) );
+ $this->mCompressed = false;
}
}
+
+ /** @todo document */
function __sleep() {
- compress();
+ $this->compress();
+ return array( 'mVersion', 'mCompressed', 'mItems', 'mDefaultHash' );
}
+ /** @todo document */
function __wakeup() {
- uncompress();
+ $this->uncompress();
+ }
+
+ /**
+ * Determines if this object is happy
+ */
+ public 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();
+
+
+/**
+ * @todo document (needs one-sentence top-level class description + some function descriptions).
+ */
+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 = 'HistoryBlobStub::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;
+ }
+ $row->old_text=ExternalStore::fetchFromUrl($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.
+ */
+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;
}
}
-?>
dépôts / lhc / web / wiklou.git / blobdiff