Make math usable without RESTbase

* Do not contact RESTbase in texvc rendering mode and
  use the well established tex checking that is already build
  into texvc.
* Do not use RESTbase in LaTeXML mode.

Background:
In I1982612e8c6a356e3dbdf447724ac82e5968cc77 RESTbased replaced
texvccheck that was a derivate of texvc designed for people
that wanted to use secure MathML rendering using mathoid.
The integration of mathoid to restbase made this feature obsolete.
However, texvccheck was not only used to check the latex input
that was sent to mathoid, but also the string which was sent to texvc.
Since texvc has already build in tex checking this is not
required and does not improve security.
Finally, users updating from old versions of the math extension
(prior to 2014) that do not have textexvccheck installed,
do not need to compile the texvccheck binary after this change.

PS5: Also treats the case where VisualEditor is not installed.

Bug: T121173
Change-Id: I1bd076b09206869b5ed75280d22e1b36bfb8d8ad

MathInputCheckRestbase.php

@@ -38,6 +38,17 @@ class MathInputCheckRestbase extends MathInputCheck {
 		if ( isset( $e->error->message ) ){
 			if ( $e->error->message === 'Illegal TeX function' ) {
 				return $errorRenderer->getError( 'math_unknown_function', $e->error->found );
+			} elseif ( preg_match( '/Math extension/', $e->error->message ) ) {
+				$names = MathHooks::getMathNames();
+				$mode = $names['mathml'];
+				try {
+					$host = $this->restbaseInterface->getUrl( '' );
+				}
+				catch ( Exception $ignore ) {
+					$host = 'invalid';
+				}
+				$msg = $e->error->message;
+				return $errorRenderer->getError( 'math_invalidresponse', $mode, $host, $msg );
 			}
 			return $errorRenderer->getError( 'math_syntax_error' );
 		}

MathMathML.php

@@ -86,7 +86,7 @@ class MathMathML extends MathRenderer {
 	 * @see MathRenderer::render()
 	*/
 	public function render( $forceReRendering = false ) {
-		if ( $this->inputType == 'tex' ) {
+		if ( $this->inputType == 'tex' && $this->mode == 'mathml' ) {
 			$tex = $this->getTex();
 			$displaystyle = false;
 			if ( $this->getMathStyle() == 'inlineDisplaystyle' ) {

MathRenderer.php

@@ -573,14 +573,16 @@ abstract class MathRenderer {
 				}
 			}
 			$checker = new MathInputCheckRestbase( $this->userInputTex );
-			if ( $checker->isValid() ) {
-				$this->setTex( $checker->getValidTex() );
-				$this->texSecure = true;
-				return true;
-			} else {
-				$this->lastError = $checker->getError();
-				return false;
+			try {
+				if ( $checker->isValid() ) {
+					$this->setTex( $checker->getValidTex() );
+					$this->texSecure = true;
+					return true;
+				}
+			} catch ( MWException $e ) {
 			}
+			$this->lastError = $checker->getError();
+			return false;
 		}
 	}
 

MathRestbaseInterface.php

@@ -43,7 +43,7 @@ class MathRestbaseInterface {
 		$this->calculateHash();
 		$request = array(
 			'method' => 'GET',
-			'url'    => self::getUrl( "media/math/render/$type/{$this->hash}" )
+			'url'    => $this->getUrl( "media/math/render/$type/{$this->hash}" )
 		);
 		$serviceClient = $this->getServiceClient();
 		$response = $serviceClient->run( $request );
@@ -83,6 +83,9 @@ class MathRestbaseInterface {
 			if ( isset( $json->detail ) && isset( $json->detail->success ) ) {
 				$this->success = $json->detail->success;
 				$this->error = $json->detail;
+			} else {
+				$this->success = false;
+				$this->setErrorMessage( 'Math extension cannot connect to Restbase.' );
 			}
 			return false;
 		}
@@ -104,7 +107,7 @@ class MathRestbaseInterface {
 			'body'   => $post
 		);
 		$serviceClient = $this->getServiceClient();
-		$request['url'] = self::getUrl( "media/math/check/{$this->type}" );
+		$request['url'] = $this->getUrl( "media/math/check/{$this->type}" );
 		$response = $serviceClient->run( $request );
 		if ( $response['code'] === 200 ) {
 			$res = $response['body'];
@@ -156,7 +159,7 @@ class MathRestbaseInterface {
 	 * @return string
 	 * @throws MWException
 	 */
-	private static function getUrl( $path, $internal = true ) {
+	public function getUrl( $path, $internal = true ) {
 		global $wgVirtualRestConfig, $wgMathFullRestbaseURL, $wgVisualEditorFullRestbaseURL;
 		if ( $internal && isset( $wgVirtualRestConfig['modules']['restbase'] ) ) {
 			return "/mathoid/local/v1/$path";
@@ -167,8 +170,9 @@ class MathRestbaseInterface {
 		if ( $wgVisualEditorFullRestbaseURL ) {
 			return "{$wgVisualEditorFullRestbaseURL}v1/$path";
 		}
-		throw new MWException( 'Math extension can not find Restbase URL.'.
-			' Please specify $wgMathFullRestbaseURL.' );
+		$msg = 'Math extension can not find Restbase URL. Please specify $wgMathFullRestbaseURL.';
+		$this->setErrorMessage( $msg );
+		throw new MWException( $msg );
 	}
 
 	/**
@@ -190,7 +194,7 @@ class MathRestbaseInterface {
 		try {
 			$request = array(
 				'method' => 'GET',
-				'url'    => self::getUrl( '?spec' )
+				'url'    => $this->getUrl( '?spec' )
 			);
 		} catch ( Exception $e ) {
 			return false;
@@ -244,7 +248,7 @@ class MathRestbaseInterface {
 	 */
 	public function getFullSvgUrl() {
 		$this->calculateHash();
-		return self::getUrl( "media/math/render/svg/{$this->hash}", false );
+		return $this->getUrl( "media/math/render/svg/{$this->hash}", false );
 	}
 
 	/**
@@ -289,4 +293,11 @@ class MathRestbaseInterface {
 		return $this->type;
 	}
 
+	private function setErrorMessage( $msg ) {
+		$this->error = (object)array(
+				'error' =>
+						(object)array( 'message' => $msg )
+		);
+	}
+
 }

MathTexvc.php

@@ -465,4 +465,18 @@ class MathTexvc extends MathRenderer {
 	public function setOutputHash( $hash ) {
 		$this->hash = $hash;
 	}
+
+	/**
+	 * Skip tex check for texvc rendering mode.
+	 * Checking the tex code in texvc mode just adds a dependency to the
+	 * texvccheck binary which does not improve security since the same
+	 * checks are performed by texvc anyhow. Especially given the fact that
+	 * texvccheck was derived from texvc.
+	 * @return bool
+	 */
+	public function checkTex() {
+		return true;
+	}
+
+
 }