mediawiki-extensions-Cite/src/ReferenceStack.php
Thiemo Kreuz 7fbd5de7f5 Merge two code paths related to follow
This patch also adds a test case that was missing before. If a
follow="…" is followed by another, normal <ref>, the internal key
(a.k.a. $this->refSequence) is not incremented. This was the case
before, just not covered by any test.

Change-Id: I102d1e67a6918017acc7e4a4663b08c828d101a6
2020-05-12 10:52:08 +02:00

418 lines
12 KiB
PHP

<?php
namespace Cite;
use LogicException;
use Parser;
use StripState;
/**
* Encapsulates most of Cite state during parsing. This includes metadata about each ref tag,
* and a rollback stack to correct confusion caused by lost context when `{{#tag` is used.
*
* @license GPL-2.0-or-later
*/
class ReferenceStack {
/**
* Data structure representing all <ref> tags parsed so far, indexed by group name (an empty
* string for the default group) and reference name.
*
* References without a name get a numeric index, starting from 0. Conflicts are avoided by
* disallowing numeric names (e.g. <ref name="1">) in {@see Cite::validateRef}.
*
* Elements (almost all are optional):
* - 'name': The original name="…" of a reference (also used as the array key), or null for
* anonymous references.
* - 'key': Sequence number for all references, no matter which group, starting from 1. Used to
* generate IDs and anchors.
* - 'number': Sequence number per group, starting from 1. To be used in the [1] footnote
* marker.
* - 'extendsIndex': Sequence number for sub-references with the same extends="…", starting
* from 1. Used in addition to the 'number' in [1.1] footnote markers.
* - 'count': How often a reference is reused. 0 means not reused, i.e. the reference appears
* only one time. -1 for anonymous references that cannot be reused.
* - 'extends': Marks a sub-reference. Points to the parent reference by name.
* - 'follow': Marks an incomplete follow="…". This is valid e.g. in the Page:… namespace on
* Wikisource.
* - '__placeholder__': Temporarily marks an incomplete parent reference that was referenced via
* extends="…" before it exists.
* - 'text': The content inside the <ref>…</ref> tag. Null for <ref /> without content. Also
* null for <ref></ref> without any non-whitespace content.
* - 'dir': Direction of the text. Should either be "ltr" or "rtl".
*
* @var array[][]
*/
private $refs = [];
/**
* Auto-incrementing sequence number for all <ref>, no matter which group
*
* @var int
*/
private $refSequence = 0;
/**
* Counter for the number of refs in each group.
* @var int[]
*/
private $groupRefSequence = [];
/**
* @var int[][]
*/
private $extendsCount = [];
/**
* <ref> call stack
* Used to cleanup out of sequence ref calls created by #tag
* See description of function rollbackRef.
*
* @var (array|false)[]
*/
private $refCallStack = [];
/**
* @deprecated We should be able to push this responsibility to calling code.
* @var ErrorReporter
*/
private $errorReporter;
/**
* @param ErrorReporter $errorReporter
*/
public function __construct( ErrorReporter $errorReporter ) {
$this->errorReporter = $errorReporter;
}
/**
* Leave a mark in the stack which matches an invalid ref tag.
*/
public function pushInvalidRef() {
$this->refCallStack[] = false;
}
/**
* Populate $this->refs and $this->refCallStack based on input and arguments to <ref>
*
* @param Parser $parser
* @param StripState $stripState
* @param ?string $text Content from the <ref> tag
* @param string[] $argv
* @param string $group
* @param ?string $name
* @param ?string $extends
* @param ?string $follow Guaranteed to not be a numeric string
* @param ?string $dir ref direction
*
* @return ?array ref structure, or null if no footnote marker should be rendered
* @suppress PhanTypePossiblyInvalidDimOffset To many complaints about array indizes
*/
public function pushRef(
Parser $parser,
StripState $stripState,
?string $text,
array $argv,
string $group,
?string $name,
?string $extends,
?string $follow,
?string $dir
) : ?array {
if ( !isset( $this->refs[$group] ) ) {
$this->refs[$group] = [];
$this->groupRefSequence[$group] = 0;
}
$ref = [
'count' => $name ? 0 : -1,
'dir' => $dir,
// This assumes we are going to register a new reference, instead of reusing one
'key' => ++$this->refSequence,
'name' => $name,
'text' => $text,
];
if ( $follow ) {
if ( !isset( $this->refs[$group][$follow] ) ) {
// Mark an incomplete follow="…" as such. This is valid e.g. in the Page:… namespace
// on Wikisource.
$this->refs[$group][] = $ref + [ 'follow' => $follow ];
$this->refCallStack[] = [ 'new', $this->refSequence, $group, $name, $extends, $text,
$argv ];
} elseif ( $text !== null ) {
// We know the parent already, so just perform the follow="…" and bail out
$this->appendText( $group, $follow, ' ' . $text );
$this->refSequence--;
}
// A follow="…" never gets its own footnote marker
return null;
}
if ( !$name ) {
// This is an anonymous reference, which will be given a numeric index.
$this->refs[$group][] = &$ref;
$action = 'new';
} elseif ( isset( $this->refs[$group][$name]['__placeholder__'] ) ) {
// Populate a placeholder.
unset( $this->refs[$group][$name]['__placeholder__'] );
unset( $ref['number'] );
$ref = array_merge( $ref, $this->refs[$group][$name] );
$this->refs[$group][$name] =& $ref;
$action = 'new-from-placeholder';
} elseif ( !isset( $this->refs[$group][$name] ) ) {
// Valid key with first occurrence
$this->refs[$group][$name] = &$ref;
$action = 'new';
} else {
// Change an existing entry.
$ref = &$this->refs[$group][$name];
$ref['count']++;
// Rollback the global counter since we won't create a new ref.
$this->refSequence--;
if ( $ref['text'] === null && $text !== null ) {
// If no text was set before, use this text
$ref['text'] = $text;
// Use the dir parameter only from the full definition of a named ref tag
$ref['dir'] = $dir;
$action = 'assign';
} else {
if ( $text !== null
// T205803 different strip markers might hide the same text
&& $stripState->unstripBoth( $text )
!== $stripState->unstripBoth( $ref['text'] )
) {
// two refs with same name and different text
// add error message to the original ref
// TODO: standardize error display and move to `validateRef`.
$ref['text'] .= ' ' . $this->errorReporter->plain(
$parser, 'cite_error_references_duplicate_key', $name
);
}
$action = 'increment';
}
}
$ref['number'] = $ref['number'] ?? ++$this->groupRefSequence[$group];
// Do not mess with a known parent a second time
if ( $extends && !isset( $ref['extendsIndex'] ) ) {
$this->extendsCount[$group][$extends] =
( $this->extendsCount[$group][$extends] ?? 0 ) + 1;
$ref['extends'] = $extends;
$ref['extendsIndex'] = $this->extendsCount[$group][$extends];
if ( isset( $this->refs[$group][$extends]['number'] ) ) {
// Adopt the parent's number.
$ref['number'] = $this->refs[$group][$extends]['number'];
// Roll back the group sequence number.
--$this->groupRefSequence[$group];
} else {
// Transfer my number to parent ref.
$this->refs[$group][$extends] = [
'number' => $ref['number'],
'__placeholder__' => true,
];
}
} elseif ( $extends && $ref['extends'] !== $extends ) {
// TODO: Change the error message to talk about "conflicting content or parent"?
$error = $this->errorReporter->plain( $parser, 'cite_error_references_duplicate_key',
$name );
if ( isset( $ref['text'] ) ) {
$ref['text'] .= ' ' . $error;
} else {
$ref['text'] = $error;
}
}
$this->refCallStack[] = [ $action, $ref['key'], $group, $name, $extends, $text, $argv ];
return $ref;
}
/**
* Undo the changes made by the last $count ref tags. This is used when we discover that the
* last few tags were actually inside of a references tag.
*
* @param int $count
*
* @return array[] Refs to restore under the correct context, as a list of [ $text, $argv ]
*/
public function rollbackRefs( int $count ) : array {
$redoStack = [];
while ( $count-- && $this->refCallStack ) {
$call = array_pop( $this->refCallStack );
if ( $call ) {
$redoStack[] = $this->rollbackRef( ...$call );
}
}
// Drop unused rollbacks, this group is finished.
$this->refCallStack = [];
return array_reverse( $redoStack );
}
/**
* Partially undoes the effect of calls to stack()
*
* Called by guardedReferences()
*
* The option to define <ref> within <references> makes the
* behavior of <ref> context dependent. This is normally fine
* but certain operations (especially #tag) lead to out-of-order
* parser evaluation with the <ref> tags being processed before
* their containing <reference> element is read. This leads to
* stack corruption that this function works to fix.
*
* This function is not a total rollback since some internal
* counters remain incremented. Doing so prevents accidentally
* corrupting certain links.
*
* @param string $action
* @param int $key Autoincrement counter for this ref.
* @param string $group
* @param ?string $name The name attribute passed in the ref tag.
* @param ?string $extends
* @param ?string $text
* @param array $argv
*
* @return array [ $text, $argv ] Ref redo item.
*/
private function rollbackRef(
string $action,
int $key,
string $group,
?string $name,
?string $extends,
?string $text,
array $argv
) : array {
if ( !$this->hasGroup( $group ) ) {
throw new LogicException( "Cannot roll back ref with unknown group \"$group\"." );
}
$lookup = $name ?: null;
if ( $lookup === null ) {
// Find anonymous ref by key.
foreach ( $this->refs[$group] as $k => $v ) {
if ( isset( $this->refs[$group][$k]['key'] ) &&
$this->refs[$group][$k]['key'] === $key
) {
$lookup = $k;
break;
}
}
}
// Obsessive sanity checks that the specified element exists.
if ( $lookup === null ) {
throw new LogicException( "Cannot roll back unknown ref by key $key." );
} elseif ( !isset( $this->refs[$group][$lookup] ) ) {
throw new LogicException( "Cannot roll back missing named ref \"$lookup\"." );
} elseif ( $this->refs[$group][$lookup]['key'] !== $key ) {
throw new LogicException(
"Cannot roll back corrupt named ref \"$lookup\" which should have had key $key." );
}
if ( $extends ) {
$this->extendsCount[$group][$extends]--;
}
switch ( $action ) {
case 'new':
// Rollback the addition of new elements to the stack
unset( $this->refs[$group][$lookup] );
if ( !$this->refs[$group] ) {
$this->popGroup( $group );
} elseif ( isset( $this->groupRefSequence[$group] ) ) {
$this->groupRefSequence[$group]--;
}
// TODO: Don't we need to rollback extendsCount as well?
break;
case 'new-from-placeholder':
$this->refs[$group][$lookup]['__placeholder__'] = true;
unset( $this->refs[$group][$lookup]['count'] );
break;
case 'assign':
// Rollback assignment of text to pre-existing elements
$this->refs[$group][$lookup]['text'] = null;
$this->refs[$group][$lookup]['count']--;
break;
case 'increment':
// Rollback increase in named ref occurrences
$this->refs[$group][$lookup]['count']--;
break;
default:
throw new LogicException( "Unknown call stack action \"$action\"" );
}
return [ $text, $argv ];
}
/**
* Clear state for a single group.
*
* @param string $group
*
* @return array[] The references from the removed group
*/
public function popGroup( string $group ) : array {
$refs = $this->getGroupRefs( $group );
unset( $this->refs[$group] );
unset( $this->groupRefSequence[$group] );
unset( $this->extendsCount[$group] );
return $refs;
}
/**
* Retruns true if the group exists and contains references.
*
* @param string $group
*
* @return bool
*/
public function hasGroup( string $group ) : bool {
return isset( $this->refs[$group] ) && $this->refs[$group];
}
/**
* Returns a list of all groups with references.
*
* @return string[]
*/
public function getGroups() : array {
$groups = [];
foreach ( $this->refs as $group => $refs ) {
if ( $refs ) {
$groups[] = $group;
}
}
return $groups;
}
/**
* Return all references for a group.
*
* @param string $group
*
* @return array[]
*/
public function getGroupRefs( string $group ) : array {
return $this->refs[$group] ?? [];
}
/**
* @param string $group
* @param string $name
* @param string $text
*/
public function appendText( string $group, string $name, string $text ) {
if ( isset( $this->refs[$group][$name]['text'] ) ) {
$this->refs[$group][$name]['text'] .= $text;
} else {
$this->refs[$group][$name]['text'] = $text;
}
}
}