From 2262cd4b6d08bc5644a45e557b00fb51caf717f5 Mon Sep 17 00:00:00 2001
From: Nick Hu <me@nickhu.co.uk>
Date: Wed, 8 Sep 2021 17:01:12 +0100
Subject: [PATCH] Gate LaTeX maths behind labs flag

---
 .../app/features/html/EventHtmlRenderer.kt    | 37 +++++++++++--------
 .../features/settings/VectorPreferences.kt    |  5 +++
 vector/src/main/res/values/strings.xml        |  1 +
 .../src/main/res/xml/vector_settings_labs.xml |  5 +++
 4 files changed, 33 insertions(+), 15 deletions(-)

diff --git a/vector/src/main/java/im/vector/app/features/html/EventHtmlRenderer.kt b/vector/src/main/java/im/vector/app/features/html/EventHtmlRenderer.kt
index e2fb385ae5..5c950b43e9 100644
--- a/vector/src/main/java/im/vector/app/features/html/EventHtmlRenderer.kt
+++ b/vector/src/main/java/im/vector/app/features/html/EventHtmlRenderer.kt
@@ -20,6 +20,7 @@ import android.content.Context
 import android.text.Spannable
 import androidx.core.text.toSpannable
 import im.vector.app.core.resources.ColorProvider
+import im.vector.app.features.settings.VectorPreferences
 import io.noties.markwon.AbstractMarkwonPlugin
 import io.noties.markwon.Markwon
 import io.noties.markwon.MarkwonPlugin
@@ -34,27 +35,33 @@ import javax.inject.Singleton
 
 @Singleton
 class EventHtmlRenderer @Inject constructor(htmlConfigure: MatrixHtmlPluginConfigure,
-                                            context: Context) {
+                                            context: Context,
+                                            private val vectorPreferences: VectorPreferences) {
 
     interface PostProcessor {
         fun afterRender(renderedText: Spannable)
     }
 
-    private val markwon = Markwon.builder(context)
+    private val builder = Markwon.builder(context)
             .usePlugin(HtmlPlugin.create(htmlConfigure))
-            .usePlugin(object : AbstractMarkwonPlugin() { // Markwon expects maths to be in a specific format: https://noties.io/Markwon/docs/v4/ext-latex
-                override fun processMarkdown(markdown: String): String {
-                    return markdown
-                            .replace(Regex("""<span\s+data-mx-maths="([^"]*)">.*?</span>""")) { matchResult -> "$$" + matchResult.groupValues[1] + "$$" }
-                            .replace(Regex("""<div\s+data-mx-maths="([^"]*)">.*?</div>""")) { matchResult -> "\n$$\n" + matchResult.groupValues[1] + "\n$$\n" }
-                }
-            })
-            .usePlugin(MarkwonInlineParserPlugin.create())
-            .usePlugin(JLatexMathPlugin.create(44F) { builder ->
-                builder.inlinesEnabled(true)
-                builder.theme().inlinePadding(JLatexMathTheme.Padding.symmetric(24, 8))
-            })
-            .build()
+
+    private val markwon = if (vectorPreferences.latexMathsIsEnabled()) {
+        builder
+                .usePlugin(object : AbstractMarkwonPlugin() { // Markwon expects maths to be in a specific format: https://noties.io/Markwon/docs/v4/ext-latex
+                    override fun processMarkdown(markdown: String): String {
+                        return markdown
+                                .replace(Regex("""<span\s+data-mx-maths="([^"]*)">.*?</span>""")) { matchResult -> "$$" + matchResult.groupValues[1] + "$$" }
+                                .replace(Regex("""<div\s+data-mx-maths="([^"]*)">.*?</div>""")) { matchResult -> "\n$$\n" + matchResult.groupValues[1] + "\n$$\n" }
+                    }
+                })
+                .usePlugin(MarkwonInlineParserPlugin.create())
+                .usePlugin(JLatexMathPlugin.create(44F) { builder ->
+                    builder.inlinesEnabled(true)
+                    builder.theme().inlinePadding(JLatexMathTheme.Padding.symmetric(24, 8))
+                })
+    } else {
+        builder
+    }.build()
 
     val plugins: List<MarkwonPlugin> = markwon.plugins
 
diff --git a/vector/src/main/java/im/vector/app/features/settings/VectorPreferences.kt b/vector/src/main/java/im/vector/app/features/settings/VectorPreferences.kt
index 0b7b495f48..1e673e7b4f 100755
--- a/vector/src/main/java/im/vector/app/features/settings/VectorPreferences.kt
+++ b/vector/src/main/java/im/vector/app/features/settings/VectorPreferences.kt
@@ -100,6 +100,7 @@ class VectorPreferences @Inject constructor(private val context: Context) {
         private const val SETTINGS_SEND_MESSAGE_WITH_ENTER = "SETTINGS_SEND_MESSAGE_WITH_ENTER"
         private const val SETTINGS_ENABLE_CHAT_EFFECTS = "SETTINGS_ENABLE_CHAT_EFFECTS"
         private const val SETTINGS_SHOW_EMOJI_KEYBOARD = "SETTINGS_SHOW_EMOJI_KEYBOARD"
+        private const val SETTINGS_LABS_ENABLE_LATEX_MATHS = "SETTINGS_LABS_ENABLE_LATEX_MATHS"
 
         // Room directory
         private const val SETTINGS_ROOM_DIRECTORY_SHOW_ALL_PUBLIC_ROOMS = "SETTINGS_ROOM_DIRECTORY_SHOW_ALL_PUBLIC_ROOMS"
@@ -337,6 +338,10 @@ class VectorPreferences @Inject constructor(private val context: Context) {
         return defaultPrefs.getBoolean(SETTINGS_LABS_UNREAD_NOTIFICATIONS_AS_TAB, false)
     }
 
+    fun latexMathsIsEnabled(): Boolean {
+        return defaultPrefs.getBoolean(SETTINGS_LABS_ENABLE_LATEX_MATHS, false)
+    }
+
     fun failFast(): Boolean {
         return BuildConfig.DEBUG || (developerMode() && defaultPrefs.getBoolean(SETTINGS_DEVELOPER_MODE_FAIL_FAST_PREFERENCE_KEY, false))
     }
diff --git a/vector/src/main/res/values/strings.xml b/vector/src/main/res/values/strings.xml
index 453b5ba432..f96320175a 100644
--- a/vector/src/main/res/values/strings.xml
+++ b/vector/src/main/res/values/strings.xml
@@ -3595,4 +3595,5 @@
     <string name="link_this_email_settings_link">Link this email with your account</string>
     <!-- %s will be replaced by the value of link_this_email_settings_link and styled as a link -->
     <string name="link_this_email_with_your_account">%s in Settings to receive invites directly in Element.</string>
+    <string name="labs_enable_latex_maths">Enable LaTeX mathematics</string>
 </resources>
diff --git a/vector/src/main/res/xml/vector_settings_labs.xml b/vector/src/main/res/xml/vector_settings_labs.xml
index 6260f65fd9..e7f06bc3b3 100644
--- a/vector/src/main/res/xml/vector_settings_labs.xml
+++ b/vector/src/main/res/xml/vector_settings_labs.xml
@@ -50,6 +50,11 @@
         android:key="SETTINGS_LABS_USE_RESTRICTED_JOIN_RULE"
         android:title="@string/labs_use_restricted_join_rule"
         android:summary="@string/labs_use_restricted_join_rule_desc"/>
+
+    <im.vector.app.core.preference.VectorSwitchPreference
+        android:defaultValue="false"
+        android:key="SETTINGS_LABS_ENABLE_LATEX_MATHS"
+        android:title="@string/labs_enable_latex_maths"/>
     <!--</im.vector.app.core.preference.VectorPreferenceCategory>-->