From 292f8a3850c3450c117850a8836538d3eda356f2 Mon Sep 17 00:00:00 2001
From: Vitor Pamplona <vitor@vitorpamplona.com>
Date: Mon, 6 Apr 2026 19:22:24 -0400
Subject: [PATCH] Migrates the SHA256 hasher out of the threadpool

---
 .../EventHasherSerializer.jvmAndroid.kt       |  5 +++--
 .../crypto/HashingByteArrayBuilder.kt         | 11 +++-------
 .../quartz/utils/sha256/Sha256.jvmAndroid.kt  | 21 ++++++++++---------
 3 files changed, 17 insertions(+), 20 deletions(-)

diff --git a/quartz/src/jvmAndroid/kotlin/com/vitorpamplona/quartz/nip01Core/crypto/EventHasherSerializer.jvmAndroid.kt b/quartz/src/jvmAndroid/kotlin/com/vitorpamplona/quartz/nip01Core/crypto/EventHasherSerializer.jvmAndroid.kt
index 53b83e0bd..fc98a34b8 100644
--- a/quartz/src/jvmAndroid/kotlin/com/vitorpamplona/quartz/nip01Core/crypto/EventHasherSerializer.jvmAndroid.kt
+++ b/quartz/src/jvmAndroid/kotlin/com/vitorpamplona/quartz/nip01Core/crypto/EventHasherSerializer.jvmAndroid.kt
@@ -32,7 +32,7 @@ import com.vitorpamplona.quartz.nip01Core.core.HexKey
 import com.vitorpamplona.quartz.nip01Core.core.fastForEach
 import com.vitorpamplona.quartz.nip01Core.jackson.JacksonMapper
 import com.vitorpamplona.quartz.utils.Hex
-import com.vitorpamplona.quartz.utils.sha256.pool
+import com.vitorpamplona.quartz.utils.sha256.threadLocalDigest
 import java.io.IOException
 
 actual object EventHasherSerializer {
@@ -127,7 +127,8 @@ actual object EventHasherSerializer {
         content: String,
     ): Boolean {
         val br: BufferRecycler = JacksonMapper.mapper.factory._getBufferRecycler()
-        val bb = HashingByteArrayBuilder(br, pool)
+        val digest = threadLocalDigest.get()
+        val bb = HashingByteArrayBuilder(br, digest)
         try {
             val generator = JacksonMapper.mapper.createGenerator(bb, JsonEncoding.UTF8)
             generator.enable(JsonGenerator.Feature.COMBINE_UNICODE_SURROGATES_IN_UTF8)
diff --git a/quartz/src/jvmAndroid/kotlin/com/vitorpamplona/quartz/nip01Core/crypto/HashingByteArrayBuilder.kt b/quartz/src/jvmAndroid/kotlin/com/vitorpamplona/quartz/nip01Core/crypto/HashingByteArrayBuilder.kt
index 2b832bad1..d6bda4442 100644
--- a/quartz/src/jvmAndroid/kotlin/com/vitorpamplona/quartz/nip01Core/crypto/HashingByteArrayBuilder.kt
+++ b/quartz/src/jvmAndroid/kotlin/com/vitorpamplona/quartz/nip01Core/crypto/HashingByteArrayBuilder.kt
@@ -21,8 +21,8 @@
 package com.vitorpamplona.quartz.nip01Core.crypto
 
 import com.fasterxml.jackson.core.util.BufferRecycler
-import com.vitorpamplona.quartz.utils.sha256.Sha256Pool
 import java.io.OutputStream
+import java.security.MessageDigest
 import kotlin.math.max
 import kotlin.math.min
 
@@ -34,20 +34,15 @@ import kotlin.math.min
  */
 class HashingByteArrayBuilder(
     private val bufferRecycler: BufferRecycler,
-    private val hashPool: Sha256Pool,
+    private val hasher: MessageDigest,
 ) : OutputStream() {
     var buf: ByteArray = bufferRecycler.allocByteBuffer(BufferRecycler.BYTE_WRITE_CONCAT_BUFFER)
     var bufLength: Int = 0
 
-    // lazy minimizes lock conflicts with the pool
-    val hasher by lazy {
-        hashPool.acquire()
-    }
-
     fun release() {
         bufLength = 0
         bufferRecycler.releaseByteBuffer(BufferRecycler.BYTE_WRITE_CONCAT_BUFFER, buf)
-        hashPool.release(hasher)
+        hasher.reset()
         buf = EMPTY_ARRAY
     }
 
diff --git a/quartz/src/jvmAndroid/kotlin/com/vitorpamplona/quartz/utils/sha256/Sha256.jvmAndroid.kt b/quartz/src/jvmAndroid/kotlin/com/vitorpamplona/quartz/utils/sha256/Sha256.jvmAndroid.kt
index 5ac3608ba..0dc972d8f 100644
--- a/quartz/src/jvmAndroid/kotlin/com/vitorpamplona/quartz/utils/sha256/Sha256.jvmAndroid.kt
+++ b/quartz/src/jvmAndroid/kotlin/com/vitorpamplona/quartz/utils/sha256/Sha256.jvmAndroid.kt
@@ -30,16 +30,13 @@ import java.security.MessageDigest
  * (lock acquire + release) for ~2µs of actual hashing. ThreadLocal eliminates all locking
  * since each thread gets its own MessageDigest instance. digest() implicitly resets state.
  */
-private val threadLocalDigest =
+val threadLocalDigest =
     ThreadLocal.withInitial {
         MessageDigest.getInstance("SHA-256")
     }
 
 actual fun sha256(data: ByteArray): ByteArray = threadLocalDigest.get().digest(data)
 
-/** Pool for incremental hashing (used by EventHasherSerializer, HashingByteArrayBuilder). */
-val pool = Sha256Pool(25)
-
 /**
  * Calculate SHA256 hash while counting bytes read from the stream.
  * Returns both the hash and the number of bytes processed.
@@ -55,11 +52,15 @@ fun sha256StreamWithCount(
 ): Pair<ByteArray, Long> {
     val countingStream = CountingInputStream(inputStream)
     val digest = threadLocalDigest.get()
-    val buffer = ByteArray(bufferSize)
-    var bytesRead: Int
-    while (countingStream.read(buffer).also { bytesRead = it } != -1) {
-        digest.update(buffer, 0, bytesRead)
+    try {
+        val buffer = ByteArray(bufferSize)
+        var bytesRead: Int
+        while (countingStream.read(buffer).also { bytesRead = it } != -1) {
+            digest.update(buffer, 0, bytesRead)
+        }
+        return Pair(digest.digest(), countingStream.bytesRead)
+    } catch (e: Exception) {
+        digest.reset() // Clean up state on failure
+        throw e
     }
-    val hash = digest.digest()
-    return Pair(hash, countingStream.bytesRead)
 }