refactor(commons): unify the rich-text parser cache across Android + Desktop

Replaces the two forked cached parsers (amethyst CachedRichTextParser on
android.util.LruCache + desktop DesktopCachedRichTextParser on ConcurrentLruCache
with a naive isMarkdown) with one shared object in commons/jvmAndroid/richtext,
built on quartz ConcurrentLruCache and keeping amethyst's CommonMark-aware
computeIsMarkdown and content-addressed key (content+tags+callbackUri+authorPubKey).

- Add ConcurrentLruCache.trimToSize(maxItems) (+ tests) for the onTrimMemory path.
- Repoint all amethyst callers (incl. the markdown unit test) and both desktop
  callers; delete both forks.

Verified: :commons JVM, :desktopApp, :amethyst play debug + unit tests compile.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LUiGxXMbjVmgspa1X15o1V

amethyst/src/main/java/com/vitorpamplona/amethyst/AppModules.kt

@@ -28,6 +28,7 @@ import coil3.disk.DiskCache
 import coil3.memory.MemoryCache
 import com.vitorpamplona.amethyst.commons.model.NoteState
 import com.vitorpamplona.amethyst.commons.relayClient.BlockedRelayFilteringClient
+import com.vitorpamplona.amethyst.commons.richtext.CachedRichTextParser
 import com.vitorpamplona.amethyst.commons.robohash.CachedRobohash
 import com.vitorpamplona.amethyst.commons.scheduledposts.ScheduledPostStore
 import com.vitorpamplona.amethyst.commons.service.lnurl.OkHttpLnurlEndpointResolver
@@ -51,7 +52,6 @@ import com.vitorpamplona.amethyst.model.torState.AccountsTorStateConnector
 import com.vitorpamplona.amethyst.model.torState.TorRelayState
 import com.vitorpamplona.amethyst.napplet.DataStoreNappletPermissionStore
 import com.vitorpamplona.amethyst.napplet.DataStoreNostrSignerPermissionStore
-import com.vitorpamplona.amethyst.service.CachedRichTextParser
 import com.vitorpamplona.amethyst.service.calendar.CalendarReminderPrefs
 import com.vitorpamplona.amethyst.service.calendar.CalendarReminderWorker
 import com.vitorpamplona.amethyst.service.cast.CastRegistry

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/components/AmethystRichText.kt

@@ -35,6 +35,7 @@ import androidx.compose.ui.layout.ContentScale
 import androidx.compose.ui.platform.LocalUriHandler
 import com.vitorpamplona.amethyst.commons.model.ImmutableListOfLists
 import com.vitorpamplona.amethyst.commons.richtext.BlossomUriSegment
+import com.vitorpamplona.amethyst.commons.richtext.CachedRichTextParser
 import com.vitorpamplona.amethyst.commons.richtext.CashuSegment
 import com.vitorpamplona.amethyst.commons.richtext.ClinkOfferSegment
 import com.vitorpamplona.amethyst.commons.richtext.ConcordInviteLinkSegment
@@ -54,7 +55,6 @@ import com.vitorpamplona.amethyst.commons.ui.richtext.LocalRichTextInteractions
 import com.vitorpamplona.amethyst.commons.ui.richtext.LocalRichTextSegmentRenderer
 import com.vitorpamplona.amethyst.commons.ui.richtext.RichTextInteractions
 import com.vitorpamplona.amethyst.commons.ui.richtext.RichTextSegmentRenderer
-import com.vitorpamplona.amethyst.service.CachedRichTextParser
 import com.vitorpamplona.amethyst.ui.components.markdown.RenderContentAsMarkdown
 import com.vitorpamplona.amethyst.ui.navigation.navs.INav
 import com.vitorpamplona.amethyst.ui.navigation.routes.Route

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/components/RichTextViewer.kt

@@ -69,6 +69,7 @@ import com.vitorpamplona.amethyst.commons.model.ImmutableListOfLists
 import com.vitorpamplona.amethyst.commons.richtext.Base64Segment
 import com.vitorpamplona.amethyst.commons.richtext.BechSegment
 import com.vitorpamplona.amethyst.commons.richtext.BlossomUriSegment
+import com.vitorpamplona.amethyst.commons.richtext.CachedRichTextParser
 import com.vitorpamplona.amethyst.commons.richtext.CashuSegment
 import com.vitorpamplona.amethyst.commons.richtext.ClinkOfferSegment
 import com.vitorpamplona.amethyst.commons.richtext.ConcordInviteLinkSegment
@@ -102,7 +103,6 @@ import com.vitorpamplona.amethyst.model.LocalCache
 import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.amethyst.model.User
 import com.vitorpamplona.amethyst.model.checkForHashtagWithIcon
-import com.vitorpamplona.amethyst.service.CachedRichTextParser
 import com.vitorpamplona.amethyst.service.relayClient.reqCommand.user.UserFinderFilterAssemblerSubscription
 import com.vitorpamplona.amethyst.service.relayClient.reqCommand.user.observeUserInfo
 import com.vitorpamplona.amethyst.service.relayClient.reqCommand.user.observeUserNickname

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/feeds/PrefetchFeedMedia.kt

@@ -35,6 +35,7 @@ import coil3.imageLoader
 import coil3.request.ImageRequest
 import coil3.request.SuccessResult
 import com.vitorpamplona.amethyst.commons.model.toImmutableListOfLists
+import com.vitorpamplona.amethyst.commons.richtext.CachedRichTextParser
 import com.vitorpamplona.amethyst.commons.richtext.MediaUrlImage
 import com.vitorpamplona.amethyst.commons.richtext.MediaUrlVideo
 import com.vitorpamplona.amethyst.commons.richtext.RichTextParser
@@ -44,7 +45,6 @@ import com.vitorpamplona.amethyst.commons.ui.feeds.FeedState
 import com.vitorpamplona.amethyst.model.MediaAspectRatioCache
 import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.amethyst.model.UrlCachedPreviewer
-import com.vitorpamplona.amethyst.service.CachedRichTextParser
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
 import com.vitorpamplona.quartz.nip01Core.core.Event
 import com.vitorpamplona.quartz.nip10Notes.TextNoteEvent

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/MultiSetCompose.kt

@@ -69,11 +69,11 @@ import com.vitorpamplona.amethyst.commons.emojicoder.EmojiCoder
 import com.vitorpamplona.amethyst.commons.hashtags.Cashu
 import com.vitorpamplona.amethyst.commons.hashtags.CustomHashTagIcons
 import com.vitorpamplona.amethyst.commons.model.EmptyTagList
+import com.vitorpamplona.amethyst.commons.richtext.CachedRichTextParser
 import com.vitorpamplona.amethyst.commons.ui.components.AnimatedBorderTextCornerRadius
 import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.amethyst.model.NoteState
 import com.vitorpamplona.amethyst.model.User
-import com.vitorpamplona.amethyst.service.CachedRichTextParser
 import com.vitorpamplona.amethyst.service.relayClient.reqCommand.user.UserFinderFilterAssemblerSubscription
 import com.vitorpamplona.amethyst.service.relayClient.reqCommand.user.observeUserContactCardsScore
 import com.vitorpamplona.amethyst.service.relayClient.reqCommand.user.observeUserPicture

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/creators/previews/PreviewState.kt

@@ -21,7 +21,7 @@
 package com.vitorpamplona.amethyst.ui.note.creators.previews
 
 import androidx.compose.runtime.Stable
-import com.vitorpamplona.amethyst.service.CachedUrlParser
+import com.vitorpamplona.amethyst.commons.richtext.CachedUrlParser
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.FlowPreview
 import kotlinx.coroutines.flow.MutableStateFlow

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/elements/DisplayUncitedHashtags.kt

@@ -27,9 +27,9 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.produceState
 import com.vitorpamplona.amethyst.commons.model.toImmutableListOfLists
+import com.vitorpamplona.amethyst.commons.richtext.CachedRichTextParser
 import com.vitorpamplona.amethyst.commons.richtext.HashTagSegment
 import com.vitorpamplona.amethyst.commons.ui.components.ClickableTextColor
-import com.vitorpamplona.amethyst.service.CachedRichTextParser
 import com.vitorpamplona.amethyst.ui.navigation.navs.INav
 import com.vitorpamplona.amethyst.ui.navigation.routes.Route
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel

amethyst/src/test/java/com/vitorpamplona/amethyst/CachedRichTextParserMarkdownTest.kt

@@ -20,7 +20,7 @@
  */
 package com.vitorpamplona.amethyst
 
-import com.vitorpamplona.amethyst.service.CachedRichTextParser
+import com.vitorpamplona.amethyst.commons.richtext.CachedRichTextParser
 import org.junit.Assert.assertFalse
 import org.junit.Assert.assertTrue
 import org.junit.Test

commons/src/jvmAndroid/kotlin/com/vitorpamplona/amethyst/commons/richtext/CachedRichTextParser.kt

@@ -18,21 +18,27 @@
  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
-package com.vitorpamplona.amethyst.service
+package com.vitorpamplona.amethyst.commons.richtext
 
-import android.util.LruCache
 import com.vitorpamplona.amethyst.commons.model.ImmutableListOfLists
-import com.vitorpamplona.amethyst.commons.richtext.RichTextParser
-import com.vitorpamplona.amethyst.commons.richtext.RichTextViewerState
-import com.vitorpamplona.amethyst.commons.richtext.UrlParser
+import com.vitorpamplona.quartz.utils.cache.ConcurrentLruCache
 
+/**
+ * The shared, cross-platform cache in front of [RichTextParser]. Both Amethyst
+ * Android and Amethyst Desktop render the same parsed [RichTextViewerState] from
+ * one place, so the same content quoted in multiple notes is only parsed once.
+ *
+ * Lives in `jvmAndroid` because it depends on [ConcurrentLruCache] (a JCA-free,
+ * lock-free-read LRU that is not in `commonMain`). iOS/`commonMain` callers use
+ * the uncached [RichTextParser] directly until a KMP cache is available.
+ */
 object CachedRichTextParser {
     // Global across every feed. Sized to hold the active feed's visible + prefetched
-    // (see PrefetchFeedMedia) working set plus a few other feeds' recent entries, so
-    // pre-parsed bodies survive until the render reads them and feed switches don't
-    // thrash. Each entry is one note's parsed segments — typically single-digit KB.
-    private val richTextCache = LruCache<Int, RichTextViewerState>(500)
-    private val isMarkdownCache = LruCache<Int, Boolean>(200)
+    // working set plus a few other feeds' recent entries, so pre-parsed bodies survive
+    // until the render reads them and feed switches don't thrash. Each entry is one
+    // note's parsed segments — typically single-digit KB.
+    private val richTextCache = ConcurrentLruCache<Int, RichTextViewerState>(500)
+    private val isMarkdownCache = ConcurrentLruCache<Int, Boolean>(200)
 
     private fun hashCodeCache(
         content: String,
@@ -69,7 +75,7 @@ object CachedRichTextParser {
         tags: ImmutableListOfLists<String>,
         callbackUri: String? = null,
         authorPubKey: String? = null,
-    ): RichTextViewerState? = richTextCache[hashCodeCache(content, tags, callbackUri, authorPubKey)]
+    ): RichTextViewerState? = richTextCache.get(hashCodeCache(content, tags, callbackUri, authorPubKey))
 
     fun parseText(
         content: String,
@@ -78,13 +84,13 @@ object CachedRichTextParser {
         authorPubKey: String? = null,
     ): RichTextViewerState {
         val key = hashCodeCache(content, tags, callbackUri, authorPubKey)
-        val cached = richTextCache[key]
+        val cached = richTextCache.get(key)
         return if (cached != null) {
             cached
         } else {
-            val newUrls = RichTextParser().parseText(content, tags, callbackUri, authorPubKey)
-            richTextCache.put(key, newUrls)
-            newUrls
+            val newState = RichTextParser().parseText(content, tags, callbackUri, authorPubKey)
+            richTextCache.put(key, newState)
+            newState
         }
     }
 
@@ -92,7 +98,7 @@ object CachedRichTextParser {
     // notes only pays for the scan once. The decision is purely a function of `content`.
     fun isMarkdown(content: String): Boolean {
         val key = content.hashCode()
-        isMarkdownCache[key]?.let { return it }
+        isMarkdownCache.get(key)?.let { return it }
         val result = computeIsMarkdown(content)
         isMarkdownCache.put(key, result)
         return result
@@ -296,15 +302,15 @@ object CachedRichTextParser {
 }
 
 object CachedUrlParser {
-    private val parsedUrlsCache = LruCache<Int, List<String>>(10)
+    private val parsedUrlsCache = ConcurrentLruCache<Int, List<String>>(10)
 
-    fun cachedParseValidUrls(content: String): List<String> = parsedUrlsCache[content.hashCode()]
+    fun cachedParseValidUrls(content: String): List<String>? = parsedUrlsCache.get(content.hashCode())
 
     fun parseValidUrls(content: String): List<String> {
         if (content.isEmpty()) return emptyList()
 
         val key = content.hashCode()
-        val cached = parsedUrlsCache[key]
+        val cached = parsedUrlsCache.get(key)
         return if (cached != null) {
             cached
         } else {

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/service/DesktopCachedRichTextParser.kt

@@ -1,54 +0,0 @@
-/*
- * Copyright (c) 2025 Vitor Pamplona
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy of
- * this software and associated documentation files (the "Software"), to deal in
- * the Software without restriction, including without limitation the rights to use,
- * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
- * Software, and to permit persons to whom the Software is furnished to do so,
- * subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
- * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
- * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
- * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
- * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
- */
-package com.vitorpamplona.amethyst.desktop.service
-
-import com.vitorpamplona.amethyst.commons.model.ImmutableListOfLists
-import com.vitorpamplona.amethyst.commons.richtext.RichTextParser
-import com.vitorpamplona.amethyst.commons.richtext.RichTextViewerState
-import com.vitorpamplona.quartz.utils.cache.ConcurrentLruCache
-
-object DesktopCachedRichTextParser {
-    private const val MAX_CACHE_SIZE = 50
-
-    // Lock-free get on the feed rich-text render path; the previous access-order
-    // synchronizedMap took a monitor even on reads.
-    private val cache = ConcurrentLruCache<String, RichTextViewerState>(MAX_CACHE_SIZE)
-
-    fun parseText(
-        content: String,
-        tags: ImmutableListOfLists<String>,
-        callbackUri: String? = null,
-    ): RichTextViewerState {
-        cache.get(content)?.let { return it }
-        val state = RichTextParser().parseText(content, tags, callbackUri)
-        cache.put(content, state)
-        return state
-    }
-
-    fun isMarkdown(content: String): Boolean =
-        content.startsWith("> ") ||
-            content.startsWith("# ") ||
-            content.contains("##") ||
-            content.contains("__") ||
-            content.contains("**") ||
-            content.contains("```") ||
-            content.contains("](")
-}

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/ui/note/DesktopRichText.kt

@@ -57,6 +57,7 @@ import com.vitorpamplona.amethyst.commons.icons.symbols.Icon
 import com.vitorpamplona.amethyst.commons.icons.symbols.MaterialSymbols
 import com.vitorpamplona.amethyst.commons.richtext.Base64Segment
 import com.vitorpamplona.amethyst.commons.richtext.BechSegment
+import com.vitorpamplona.amethyst.commons.richtext.CachedRichTextParser
 import com.vitorpamplona.amethyst.commons.richtext.CashuSegment
 import com.vitorpamplona.amethyst.commons.richtext.ImageGalleryParagraph
 import com.vitorpamplona.amethyst.commons.richtext.ImageSegment
@@ -75,7 +76,6 @@ import com.vitorpamplona.amethyst.commons.ui.richtext.LocalRichTextSegmentRender
 import com.vitorpamplona.amethyst.commons.ui.richtext.RichTextInteractions
 import com.vitorpamplona.amethyst.commons.ui.richtext.RichTextSegmentRenderer
 import com.vitorpamplona.amethyst.desktop.cache.DesktopLocalCache
-import com.vitorpamplona.amethyst.desktop.service.DesktopCachedRichTextParser
 import com.vitorpamplona.quartz.lightning.LnInvoiceUtil
 import com.vitorpamplona.quartz.nip19Bech32.Nip19Parser
 import com.vitorpamplona.quartz.nip19Bech32.entities.NEvent
@@ -112,7 +112,7 @@ fun DesktopRichText(
     callbacks: RichTextCallbacks = RichTextCallbacks(),
     modifier: Modifier = Modifier,
 ) {
-    if (DesktopCachedRichTextParser.isMarkdown(content)) {
+    if (CachedRichTextParser.isMarkdown(content)) {
         RenderMarkdown(
             content = content,
             onLinkClick = { url -> handleDesktopLinkClick(url, callbacks) },

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/ui/note/NoteCard.kt

@@ -56,12 +56,12 @@ import androidx.compose.ui.unit.dp
 import coil3.compose.AsyncImage
 import com.vitorpamplona.amethyst.commons.model.EmptyTagList
 import com.vitorpamplona.amethyst.commons.model.ImmutableListOfLists
+import com.vitorpamplona.amethyst.commons.richtext.CachedRichTextParser
 import com.vitorpamplona.amethyst.commons.richtext.RichTextParser
 import com.vitorpamplona.amethyst.commons.richtext.UrlParser
 import com.vitorpamplona.amethyst.commons.ui.note.ReplyContext
 import com.vitorpamplona.amethyst.commons.ui.note.ReplyToLabel
 import com.vitorpamplona.amethyst.desktop.cache.DesktopLocalCache
-import com.vitorpamplona.amethyst.desktop.service.DesktopCachedRichTextParser
 import com.vitorpamplona.amethyst.desktop.ui.components.ToggleableTimeAgoText
 import com.vitorpamplona.amethyst.desktop.ui.media.AnimatedGifImage
 import com.vitorpamplona.amethyst.desktop.ui.media.AudioPlayer
@@ -293,7 +293,7 @@ fun NoteCard(
                 if (strippedContent.isNotBlank()) {
                     val richState =
                         remember(strippedContent, note.tags) {
-                            DesktopCachedRichTextParser.parseText(strippedContent, note.tags)
+                            CachedRichTextParser.parseText(strippedContent, note.tags)
                         }
                     DesktopRichText(
                         content = strippedContent,

quartz/src/jvmAndroid/kotlin/com/vitorpamplona/quartz/utils/cache/ConcurrentLruCache.kt

@@ -87,5 +87,19 @@ class ConcurrentLruCache<K : Any, V : Any>(
         }
     }
 
+    /**
+     * Evicts the oldest entries until at most [maxItems] remain. Used to shed
+     * memory on pressure (e.g. `onTrimMemory`). A [maxItems] of 0 or less clears
+     * the cache; values above the current size are a no-op.
+     */
+    fun trimToSize(maxItems: Int) {
+        synchronized(writeLock) {
+            while (order.size > maxItems) {
+                val oldest = order.removeFirstOrNull() ?: break
+                map.remove(oldest)
+            }
+        }
+    }
+
     fun size(): Int = map.size
 }

quartz/src/jvmAndroidTest/kotlin/com/vitorpamplona/quartz/utils/cache/ConcurrentLruCacheTest.kt

@@ -100,6 +100,38 @@ class ConcurrentLruCacheTest {
         assertNull(cache.get("a"))
     }
 
+    @Test
+    fun `trimToSize evicts oldest down to the target`() {
+        val cache = ConcurrentLruCache<String, Int>(10)
+        cache.put("a", 1)
+        cache.put("b", 2)
+        cache.put("c", 3)
+        cache.trimToSize(1)
+        assertEquals(1, cache.size())
+        // Oldest (a, b) evicted; newest (c) kept.
+        assertNull(cache.get("a"))
+        assertNull(cache.get("b"))
+        assertEquals(3, cache.get("c"))
+    }
+
+    @Test
+    fun `trimToSize above current size is a no-op`() {
+        val cache = ConcurrentLruCache<String, Int>(10)
+        cache.put("a", 1)
+        cache.put("b", 2)
+        cache.trimToSize(5)
+        assertEquals(2, cache.size())
+    }
+
+    @Test
+    fun `trimToSize to zero clears`() {
+        val cache = ConcurrentLruCache<String, Int>(10)
+        cache.put("a", 1)
+        cache.trimToSize(0)
+        assertEquals(0, cache.size())
+        assertNull(cache.get("a"))
+    }
+
     @Test
     fun `size never exceeds capacity under concurrent puts`() {
         val cap = 100