Restrict empty-frame cache entries to their parent

Remove the parser's global $mTplExpandCache, and replace it with an
alternative that is separated by parent frame. This allows the integrity
of the empty-frame expansion cache to be maintained while also allowing
parent frame access.

A page with 3 copies of
http://ja.wikipedia.org/wiki/%E4%B8%AD%E5%A4%AE%E7%B7%9A_(%E9%9F%93%E5%9B%BD)
has the following statistics: Without this change, there are 4625 cache hits
on this page, and a sample of 3 parses took 16.6, 16.9, and 16.8 seconds.
With this change, there are 2588 cache hits, and a sample of 3 parses took
16.7, 16.7, and 17.0 seconds.

Change-Id: I621e9075e0f136ac188a4d2f53418b7cc957408d

diff --git a/includes/parser/Parser.php b/includes/parser/Parser.php
index d2a20df..cf174ec 100644 (file)
--- a/includes/parser/Parser.php
+++ b/includes/parser/Parser.php
@@ -167,7 +167,6 @@ class Parser {
        var $mLinkID;
        var $mIncludeSizes, $mPPNodeCount, $mGeneratedPPNodeCount, $mHighestExpansionDepth;
        var $mDefaultSort;
-       var $mTplExpandCache; # empty-frame expansion cache
        var $mTplRedirCache, $mTplDomCache, $mHeadings, $mDoubleUnderscores;
        var $mExpensiveFunctionCount; # number of expensive parser function calls
        var $mShowToc, $mForceTocPosition;
@@ -321,7 +320,7 @@ class Parser {
                $this->mStripState = new StripState( $this->mUniqPrefix );
 
                # Clear these on every parse, bug 4549
-               $this->mTplExpandCache = $this->mTplRedirCache = $this->mTplDomCache = array();
+               $this->mTplRedirCache = $this->mTplDomCache = array();
 
                $this->mShowToc = true;
                $this->mForceTocPosition = false;
@@ -3562,12 +3561,7 @@ class Parser {
                                $text = $newFrame->expand( $text, PPFrame::RECOVER_ORIG );
                        } elseif ( $titleText !== false && $newFrame->isEmpty() ) {
                                # Expansion is eligible for the empty-frame cache
-                               if ( isset( $this->mTplExpandCache[$titleText] ) ) {
-                                       $text = $this->mTplExpandCache[$titleText];
-                               } else {
-                                       $text = $newFrame->expand( $text );
-                                       $this->mTplExpandCache[$titleText] = $text;
-                               }
+                               $text = $newFrame->cachedExpand( $titleText, $text );
                        } else {
                                # Uncached expansion
                                $text = $newFrame->expand( $text );

diff --git a/includes/parser/Preprocessor.php b/includes/parser/Preprocessor.php
index b8e262a..25b34fa 100644 (file)
--- a/includes/parser/Preprocessor.php
+++ b/includes/parser/Preprocessor.php
@@ -94,6 +94,11 @@ interface PPFrame {
         */
        function newChild( $args = false, $title = false, $indexOffset = 0 );
 
+       /**
+        * Expand a document tree node, caching the result on its parent with the given key
+        */
+       function cachedExpand( $key, $root, $flags = 0 );
+
        /**
         * Expand a document tree node
         */

diff --git a/includes/parser/Preprocessor_DOM.php b/includes/parser/Preprocessor_DOM.php
index d15b43a..4f5ebc8 100644 (file)
--- a/includes/parser/Preprocessor_DOM.php
+++ b/includes/parser/Preprocessor_DOM.php
@@ -983,6 +983,11 @@ class PPFrame_DOM implements PPFrame {
         */
        var $depth;
 
+       /**
+        * @var array
+        */
+       protected $childExpansionCache;
+
        /**
         * Construct a new preprocessor frame.
         * @param Preprocessor $preprocessor The parent preprocessor
@@ -994,6 +999,7 @@ class PPFrame_DOM implements PPFrame {
                $this->titleCache = array( $this->title ? $this->title->getPrefixedDBkey() : false );
                $this->loopCheckHash = array();
                $this->depth = 0;
+               $this->childExpansionCache = array();
        }
 
        /**
@@ -1043,6 +1049,18 @@ class PPFrame_DOM implements PPFrame {
                return new PPTemplateFrame_DOM( $this->preprocessor, $this, $numberedArgs, $namedArgs, $title );
        }
 
+       /**
+        * @throws MWException
+        * @param string|int $key
+        * @param string|PPNode_DOM|DOMDocument $root
+        * @param int $flags
+        * @return string
+        */
+       function cachedExpand( $key, $root, $flags = 0 ) {
+               // we don't have a parent, so we don't have a cache
+               return $this->expand( $root, $flags );
+       }
+
        /**
         * @throws MWException
         * @param string|PPNode_DOM|DOMDocument $root
@@ -1526,6 +1544,20 @@ class PPTemplateFrame_DOM extends PPFrame_DOM {
                return $s;
        }
 
+       /**
+        * @throws MWException
+        * @param string|int $key
+        * @param string|PPNode_DOM|DOMDocument $root
+        * @param int $flags
+        * @return string
+        */
+       function cachedExpand( $key, $root, $flags = 0 ) {
+               if ( !isset( $this->parent->childExpansionCache[$key] ) ) {
+                       $this->parent->childExpansionCache[$key] = $this->expand( $root, $flags );
+               }
+               return $this->parent->childExpansionCache[$key];
+       }
+
        /**
         * Returns true if there are no arguments in this frame
         *

diff --git a/includes/parser/Preprocessor_Hash.php b/includes/parser/Preprocessor_Hash.php
index a464461..cb652ac 100644 (file)
--- a/includes/parser/Preprocessor_Hash.php
+++ b/includes/parser/Preprocessor_Hash.php
@@ -919,6 +919,11 @@ class PPFrame_Hash implements PPFrame {
         */
        var $depth;
 
+       /**
+        * @var array
+        */
+       protected $childExpansionCache;
+
        /**
         * Construct a new preprocessor frame.
         * @param Preprocessor $preprocessor The parent preprocessor
@@ -930,6 +935,7 @@ class PPFrame_Hash implements PPFrame {
                $this->titleCache = array( $this->title ? $this->title->getPrefixedDBkey() : false );
                $this->loopCheckHash = array();
                $this->depth = 0;
+               $this->childExpansionCache = array();
        }
 
        /**
@@ -972,6 +978,18 @@ class PPFrame_Hash implements PPFrame {
                return new PPTemplateFrame_Hash( $this->preprocessor, $this, $numberedArgs, $namedArgs, $title );
        }
 
+       /**
+        * @throws MWException
+        * @param string|int $key
+        * @param string|PPNode_Hash|DOMDocument $root
+        * @param int $flags
+        * @return string
+        */
+       function cachedExpand( $key, $root, $flags = 0 ) {
+               // we don't have a parent, so we don't have a cache
+               return $this->expand( $root, $flags );
+       }
+
        /**
         * @throws MWException
         * @param string|PPNode$root
@@ -1426,6 +1444,20 @@ class PPTemplateFrame_Hash extends PPFrame_Hash {
                return $s;
        }
 
+       /**
+        * @throws MWException
+        * @param string|int $key
+        * @param string|PPNode_Hash|DOMDocument $root
+        * @param int $flags
+        * @return string
+        */
+       function cachedExpand( $key, $root, $flags = 0 ) {
+               if ( !isset( $this->parent->childExpansionCache[$key] ) ) {
+                       $this->parent->childExpansionCache[$key] = $this->expand( $root, $flags );
+               }
+               return $this->parent->childExpansionCache[$key];
+       }
+
        /**
         * Returns true if there are no arguments in this frame
         *