From 3dddf9f8cf656be08825cb37afa86b29317f25a7 Mon Sep 17 00:00:00 2001
From: Cedrick Cooke <development@cedrickc.net>
Date: Wed, 2 Nov 2022 11:10:13 -0700
Subject: [PATCH] Allow for manual cursor control (#77)

---
 core/src/jsMain/kotlin/Cursor.kt      | 16 +++++++++++
 core/src/jsMain/kotlin/Transaction.kt | 39 ++++++++++++++++++++++++---
 core/src/jsTest/kotlin/Samples.kt     |  6 ++---
 3 files changed, 55 insertions(+), 6 deletions(-)

diff --git a/core/src/jsMain/kotlin/Cursor.kt b/core/src/jsMain/kotlin/Cursor.kt
index 4e0d36d..b5d288f 100644
--- a/core/src/jsMain/kotlin/Cursor.kt
+++ b/core/src/jsMain/kotlin/Cursor.kt
@@ -12,6 +12,22 @@ public open class Cursor internal constructor(
     public val primaryKey: dynamic
         get() = cursor.primaryKey
 
+    public fun `continue`() {
+        cursor.`continue`()
+    }
+
+    public fun advance(count: Int) {
+        cursor.advance(count)
+    }
+
+    public fun `continue`(key: Key) {
+        cursor.`continue`(key.toJs())
+    }
+
+    public fun continuePrimaryKey(key: Key, primaryKey: Key) {
+        cursor.continuePrimaryKey(key.toJs(), primaryKey.toJs())
+    }
+
     public enum class Direction(internal val constant: String) {
         Next("next"),
         NextUnique("nextunique"),
diff --git a/core/src/jsMain/kotlin/Transaction.kt b/core/src/jsMain/kotlin/Transaction.kt
index 8a5203d..494c835 100644
--- a/core/src/jsMain/kotlin/Transaction.kt
+++ b/core/src/jsMain/kotlin/Transaction.kt
@@ -3,7 +3,6 @@ package com.juul.indexeddb
 import com.juul.indexeddb.external.IDBCursor
 import com.juul.indexeddb.external.IDBRequest
 import com.juul.indexeddb.external.IDBTransaction
-import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.channels.awaitClose
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.callbackFlow
@@ -46,37 +45,71 @@ public open class Transaction internal constructor(
         }
     }
 
+    @Deprecated(
+        "In the future, `autoContinue` will be a required parameter.",
+        ReplaceWith("openCursor(query, direction, cursorStart, autoContinue = true)"),
+    )
+    public suspend fun Queryable.openCursor(
+        query: Key? = null,
+        direction: Cursor.Direction = Cursor.Direction.Next,
+        cursorStart: CursorStart? = null,
+    ): Flow<CursorWithValue> = openCursor(
+        query,
+        direction,
+        cursorStart,
+        autoContinue = true,
+    )
+
     public suspend fun Queryable.openCursor(
         query: Key? = null,
         direction: Cursor.Direction = Cursor.Direction.Next,
         cursorStart: CursorStart? = null,
+        autoContinue: Boolean,
     ): Flow<CursorWithValue> = openCursorImpl(
         query,
         direction,
         cursorStart,
         open = this::requestOpenCursor,
         wrap = ::CursorWithValue,
+        autoContinue,
+    )
+
+    @Deprecated(
+        "In the future, `autoContinue` will be a required parameter.",
+        ReplaceWith("openKeyCursor(query, direction, cursorStart, autoContinue = true)"),
+    )
+    public suspend fun Queryable.openKeyCursor(
+        query: Key? = null,
+        direction: Cursor.Direction = Cursor.Direction.Next,
+        cursorStart: CursorStart? = null,
+    ): Flow<Cursor> = openKeyCursor(
+        query,
+        direction,
+        cursorStart,
+        autoContinue = true,
     )
 
     public suspend fun Queryable.openKeyCursor(
         query: Key? = null,
         direction: Cursor.Direction = Cursor.Direction.Next,
         cursorStart: CursorStart? = null,
+        autoContinue: Boolean,
     ): Flow<Cursor> = openCursorImpl(
         query,
         direction,
         cursorStart,
         open = this::requestOpenKeyCursor,
         wrap = ::Cursor,
+        autoContinue,
     )
 
-    @OptIn(ExperimentalCoroutinesApi::class)
     private suspend fun <T : Cursor, U : IDBCursor> openCursorImpl(
         query: Key?,
         direction: Cursor.Direction,
         cursorStart: CursorStart?,
         open: (Key?, Cursor.Direction) -> Request<U?>,
         wrap: (U) -> T,
+        autoContinue: Boolean,
     ): Flow<T> = callbackFlow {
         var cursorStartAction = cursorStart
         val request = open(query, direction).request
@@ -89,7 +122,7 @@ public open class Transaction internal constructor(
             } else if (cursor != null) {
                 val result = trySend(wrap(cursor))
                 when {
-                    result.isSuccess -> cursor.`continue`()
+                    result.isSuccess -> if (autoContinue) cursor.`continue`()
                     result.isFailure -> channel.close(IllegalStateException("Send failed. Did you suspend illegally?"))
                     result.isClosed -> channel.close()
                 }
diff --git a/core/src/jsTest/kotlin/Samples.kt b/core/src/jsTest/kotlin/Samples.kt
index 974fc31..6760068 100644
--- a/core/src/jsTest/kotlin/Samples.kt
+++ b/core/src/jsTest/kotlin/Samples.kt
@@ -54,7 +54,7 @@ class Samples {
         val charlie = database.transaction("customers") {
             objectStore("customers")
                 .index("name")
-                .openCursor()
+                .openCursor(autoContinue = true)
                 .map { it.value as Customer }
                 .first { it.age < 32 }
         }
@@ -73,7 +73,7 @@ class Samples {
         val skipTwoYoungest = database.transaction("customers") {
             objectStore("customers")
                 .index("age")
-                .openCursor(cursorStart = CursorStart.Advance(2))
+                .openCursor(cursorStart = CursorStart.Advance(2), autoContinue = true)
                 .map { it.value as Customer }
                 .map { it.name }
                 .toList()
@@ -83,7 +83,7 @@ class Samples {
         val skipUntil33 = database.transaction("customers") {
             objectStore("customers")
                 .index("age")
-                .openCursor(cursorStart = CursorStart.Continue(Key(33)))
+                .openCursor(cursorStart = CursorStart.Continue(Key(33)), autoContinue = true)
                 .map { it.value as Customer }
                 .map { it.name }
                 .toList()