fix: markdown link crash (#2116)

Co-authored-by: Jakub Żerko <iot.zerko@gmail.com>

app/src/androidTest/java/com/wire/android/LinkSpannableStringTest.kt

@@ -0,0 +1,103 @@
+/*
+ * Wire
+ * Copyright (C) 2023 Wire Swiss GmbH
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see http://www.gnu.org/licenses/.
+ */
+package com.wire.android
+
+import android.text.style.URLSpan
+import android.text.util.Linkify
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.wire.android.ui.common.LinkSpannableString
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class LinkSpannableStringTest {
+
+    lateinit var linkSpannableString: LinkSpannableString
+
+    @Before
+    fun setUp() {
+        linkSpannableString = LinkSpannableString("Hello, world!")
+    }
+
+    @Test
+    fun givenValidIndices_whenSetSpanIsCalled_thenSpanIsSet() {
+        // Given
+        val start = 0
+        val end = 5
+
+        // When
+        linkSpannableString.setSpan(URLSpan("http://example.com"), start, end, 0)
+
+        // Then
+        assert(linkSpannableString.getSpans(start, end, URLSpan::class.java).isNotEmpty())
+    }
+
+    @Test
+    fun givenInvalidStartIndex_whenSetSpanIsCalled_thenSpanIsNotSet() {
+        // Given
+        val start = -1
+        val end = 5
+
+        // When
+        linkSpannableString.setSpan(URLSpan("http://example.com"), start, end, 0)
+
+        // Then
+        assert(linkSpannableString.getSpans(start, end, URLSpan::class.java).isEmpty())
+    }
+
+    @Test
+    fun givenInvalidEndIndex_whenSetSpanIsCalled_thenSpanIsNotSet() {
+        // Given
+        val start = 0
+        val end = 20
+
+        // When
+        linkSpannableString.setSpan(URLSpan("http://example.com"), start, end, 0)
+
+        // Then
+        assert(linkSpannableString.getSpans(start, end, URLSpan::class.java).isEmpty())
+    }
+
+    @Test
+    fun givenASetSpan_whenRemoveSpanIsCalled_thenSpanIsRemoved() {
+        // Given
+        val urlSpan = URLSpan("http://example.com")
+        linkSpannableString.setSpan(urlSpan, 0, 5, 0)
+
+        // When
+        linkSpannableString.removeSpan(urlSpan)
+
+        // Then
+        assert(linkSpannableString.getSpans(0, 5, URLSpan::class.java).isEmpty())
+    }
+
+    @Test
+    fun givenATextWithLink_whenGetLinkInfosIsCalled_thenLinkInfoIsReturned() {
+        // Given
+        val text = "Visit http://example.com for more info."
+        val mask = Linkify.WEB_URLS
+
+        // When
+        val linkInfos = LinkSpannableString.getLinkInfos(text, mask)
+
+        // Then
+        assert(linkInfos.size == 1)
+        assert(linkInfos[0].url == "http://example.com")
+    }
+}

app/src/main/kotlin/com/wire/android/ui/common/ClickableText.kt

@@ -41,6 +41,7 @@ import androidx.compose.ui.text.TextStyle
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.text.style.TextDecoration
 import androidx.compose.ui.text.style.TextOverflow
+import com.wire.android.appLogger
 
 @Composable
 fun ClickableText(
@@ -137,7 +138,11 @@ class LinkSpannableString(source: CharSequence) : SpannableString(source) {
     }
 
     override fun setSpan(what: Any?, start: Int, end: Int, flags: Int) {
-        super.setSpan(what, start, end, flags)
-        spanList.add(Data(what, start, end))
+        if (start >= 0 && end <= this.length && start <= end) {
+            super.setSpan(what, start, end, flags)
+            spanList.add(Data(what, start, end))
+        } else {
+            appLogger.e("[LinkSpannableString] Invalid span indices: start=$start, end=$end, length=$length")
+        }
     }
 }

app/src/main/kotlin/com/wire/android/ui/markdown/MarkdownComposer.kt

@@ -52,6 +52,8 @@ import org.commonmark.node.SoftLineBreak
 import org.commonmark.node.StrongEmphasis
 import org.commonmark.node.Text
 import org.commonmark.node.ThematicBreak
+import kotlin.math.max
+import kotlin.math.min
 import org.commonmark.node.Text as nodeText
 
 @Composable
@@ -192,7 +194,7 @@ fun inlineChildren(
     return updatedMentions
 }
 
-@Suppress("LongMethod")
+@Suppress("LongMethod", "ComplexMethod")
 fun appendLinksAndMentions(
     annotatedString: AnnotatedString.Builder,
     string: String,
@@ -233,22 +235,24 @@ fun appendLinksAndMentions(
         append(stringBuilder)
         with(nodeData.colorScheme) {
             linkInfos.forEach {
-                if (it.end - it.start <= 0) {
+                val safeStart = max(it.start, 0)
+                val safeEnd = min(it.end, length - 1)
+                if (safeStart > safeEnd) {
                     return@forEach
                 }
                 addStyle(
                     style = SpanStyle(
                         color = primary,
                         textDecoration = TextDecoration.Underline
                     ),
-                    start = it.start,
-                    end = it.end
+                    start = safeStart,
+                    end = safeEnd
                 )
                 addStringAnnotation(
                     tag = TAG_URL,
                     annotation = it.url,
-                    start = it.start,
-                    end = it.end
+                    start = safeStart,
+                    end = safeEnd
                 )
             }