From bdf09125c45151dc18a93e723586dbb1071c5e0c Mon Sep 17 00:00:00 2001
From: Andreas Gohr <andi@splitbrain.org>
Date: Mon, 28 Sep 2020 16:59:46 +0200
Subject: [PATCH] set page context in Handler

Under some circumstances it is useful to know if the current parsing
process is running in a page context or not.

One of the examples is the struct plugin's use of the PARSER_HANDLER_DONE
event to automatically inject its own output instruction. Currently this
instruction is injected in each and every processing and only on rendering
is decided if there is anything to output.

This patch injects a page hint into the Handler when the handler was
created from our p_wiki_xhtml() method (and only then). Plugins can use
the getPage() method to check the context if needed.

Note: currently p_wiki_xhtml() also modifies the global $ID variable
which might also used as context hint (but will also be set during
on-the-fly renders, eg. the preview intro text).

It would probably be a good idea to check if it would be better when all
handle methods rely on getPage() instead of global $ID instead. This
would be a major change in parsing though and needs serious testing
while this addition has basically no consequences currently.
---
 inc/parser/handler.php | 26 ++++++++++++++++++++++++++
 inc/parserutils.php    | 21 +++++++++++++--------
 2 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/inc/parser/handler.php b/inc/parser/handler.php
index a3609609c..3538c78b0 100644
--- a/inc/parser/handler.php
+++ b/inc/parser/handler.php
@@ -30,6 +30,9 @@ class Doku_Handler {
     /** @var bool should blocks be rewritten? FIXME seems to always be true */
     protected $rewriteBlocks = true;
 
+    /** @var string|null the currently processed page, null for on the fly renders */
+    protected $page = null;
+
     /**
      * Doku_Handler constructor.
      */
@@ -37,6 +40,29 @@ class Doku_Handler {
         $this->callWriter = new CallWriter($this);
     }
 
+    /**
+     * Set the currently processed page
+     *
+     * @param string $id
+     */
+    public function setPage($id)
+    {
+        $this->page = $id;
+    }
+
+    /**
+     * Get the currently processed page
+     *
+     * This may return null when the parsing/handling process is called "on the fly", eg. to
+     * render a wiki text snippet somewhere.
+     *
+     * @return string|null
+     */
+    public function getPage()
+    {
+        return $this->page;
+    }
+
     /**
      * Add a new call by passing it to the current CallWriter
      *
diff --git a/inc/parserutils.php b/inc/parserutils.php
index 846be54db..ffbcc872c 100644
--- a/inc/parserutils.php
+++ b/inc/parserutils.php
@@ -80,7 +80,7 @@ function p_wiki_xhtml($id, $rev='', $excuse=true,$date_at=''){
     if($rev || $date_at){
         if(file_exists($file)){
             //no caching on old revisions
-            $ret = p_render('xhtml',p_get_instructions(io_readWikiPage($file,$id,$rev)),$info,$date_at);
+            $ret = p_render('xhtml',p_get_instructions(io_readWikiPage($file,$id,$rev), $id),$info,$date_at);
         }elseif($excuse){
             $ret = p_locale_xhtml('norev');
         }
@@ -193,27 +193,32 @@ function p_cached_instructions($file,$cacheonly=false,$id='') {
 /**
  * turns a page into a list of instructions
  *
- * @author Harry Fuecks <hfuecks@gmail.com>
+ * @param string $text raw wiki syntax text
+ * @param string $id optional hint on the currently processed page
+ * @return array a list of instruction arrays
  * @author Andreas Gohr <andi@splitbrain.org>
  *
- * @param string $text  raw wiki syntax text
- * @return array a list of instruction arrays
+ * @author Harry Fuecks <hfuecks@gmail.com>
  */
-function p_get_instructions($text){
+function p_get_instructions($text, $id=''){
 
     $modes = p_get_parsermodes();
 
     // Create the parser and handler
-    $Parser = new Parser(new Doku_Handler());
+    $handler = new Doku_Handler();
+    if($id !== '') {
+        $handler->setPage($id);
+    }
+    $parser = new Parser($handler);
 
     //add modes to parser
     foreach($modes as $mode){
-        $Parser->addMode($mode['mode'],$mode['obj']);
+        $parser->addMode($mode['mode'],$mode['obj']);
     }
 
     // Do the parsing
     Event::createAndTrigger('PARSER_WIKITEXT_PREPROCESS', $text);
-    $p = $Parser->parse($text);
+    $p = $parser->parse($text);
     //  dbg($p);
     return $p;
 }