Speed up raw mode readRawByte (#221)

mordant/api/mordant.api

@@ -1355,7 +1355,7 @@ public final class com/github/ajalt/mordant/terminal/YesNoPrompt : com/github/aj
 
 public abstract class com/github/ajalt/mordant/terminal/terminalinterface/TerminalInterfaceJvmPosix : com/github/ajalt/mordant/terminal/terminalinterface/TerminalInterfacePosix {
 	public fun <init> ()V
-	protected fun readRawByte (Lkotlin/time/TimeMark;)I
+	protected fun readRawByte ()Ljava/lang/Integer;
 }
 
 public abstract class com/github/ajalt/mordant/terminal/terminalinterface/TerminalInterfacePosix : com/github/ajalt/mordant/terminal/StandardTerminalInterface {
@@ -1369,7 +1369,7 @@ public abstract class com/github/ajalt/mordant/terminal/terminalinterface/Termin
 	public abstract fun getTermiosConstants ()Lcom/github/ajalt/mordant/terminal/terminalinterface/TerminalInterfacePosix$TermiosConstants;
 	protected abstract fun isatty (I)Z
 	public fun readInputEvent (Lkotlin/time/TimeMark;Lcom/github/ajalt/mordant/input/MouseTracking;)Lcom/github/ajalt/mordant/input/InputEvent;
-	protected abstract fun readRawByte (Lkotlin/time/TimeMark;)I
+	protected abstract fun readRawByte ()Ljava/lang/Integer;
 	public abstract fun setStdinTermios (Lcom/github/ajalt/mordant/terminal/terminalinterface/TerminalInterfacePosix$Termios;)V
 	public fun stdinInteractive ()Z
 	public fun stdoutInteractive ()Z

mordant/src/commonMain/kotlin/com/github/ajalt/mordant/internal/Utf8.kt

@@ -1,8 +1,8 @@
 package com.github.ajalt.mordant.internal
 
 /** Read bytes from a UTF-8 encoded stream, and return the next codepoint. */
-internal fun readBytesAsUtf8(readByte: () -> Int): Int {
-    val byte = readByte()
+internal fun readBytesAsUtf8(readByte: () -> Int?): Int? {
+    val byte = readByte() ?: return null
     val byteLength: Int
     var codepoint: Int
     when {
@@ -29,7 +29,7 @@ internal fun readBytesAsUtf8(readByte: () -> Int): Int {
     }
 
     repeat(byteLength - 1) {
-        val next = readByte()
+        val next = readByte() ?: return null
         if (next and 0b1100_0000 != 0b1000_0000) error("Invalid UTF-8 byte")
         codepoint = codepoint shl 6 or (next and 0b0011_1111)
     }

mordant/src/commonMain/kotlin/com/github/ajalt/mordant/terminal/TerminalInterface.kt

@@ -4,6 +4,7 @@ import com.github.ajalt.mordant.input.InputEvent
 import com.github.ajalt.mordant.input.MouseTracking
 import com.github.ajalt.mordant.rendering.AnsiLevel
 import com.github.ajalt.mordant.rendering.Size
+import kotlin.jvm.JvmInline
 import kotlin.time.Duration
 import kotlin.time.TimeMark
 
@@ -53,6 +54,7 @@ interface TerminalInterface {
      * @param timeout The point in time that this call should block to while waiting for an event.
      *   If the timeout is in the past, this method should not block.
      * @param mouseTracking The current mouse tracking mode.
+     * @return The event, or `null` if no event is available but this call should be retried
      */
     fun readInputEvent(timeout: TimeMark, mouseTracking: MouseTracking): InputEvent? {
         throw NotImplementedError("Reading input events is not supported on this terminal")

mordant/src/commonMain/kotlin/com/github/ajalt/mordant/terminal/terminalinterface/PosixEventParser.kt

@@ -13,13 +13,21 @@ private const val ESC = '\u001b'
 
 
 internal class PosixEventParser(
-    private val readRawByte: (timeout: TimeMark) -> Int,
+    private val readRawByte: () -> Int?,
 ) {
+    private fun readRawByte(timeout: TimeMark): Int? {
+        do {
+            val byte = readRawByte()
+            if (byte != null) return byte
+        } while (timeout.hasNotPassedNow())
+        return null
+    }
+
     /*
       Some patterns seen in terminal key escape codes, derived from combos seen
       at https://github.com/nodejs/node/blob/main/lib/internal/readline/utils.js
     */
-    fun readInputEvent(timeout: TimeMark): InputEvent {
+    fun readInputEvent(timeout: TimeMark): InputEvent? {
         var ctrl = false
         var alt = false
         var shift = false
@@ -28,12 +36,13 @@ internal class PosixEventParser(
         val s = StringBuilder()
         var ch: Char
 
-        fun read() {
-            ch = readRawByte(timeout).toChar()
+        fun read(): Char? {
+            ch = readRawByte(timeout)?.toChar() ?: return null
             s.append(ch)
+            return ch
         }
 
-        val first = codepointToString(readUtf8Int(timeout))
+        val first = codepointToString(readUtf8Int(timeout) ?: return null)
         if (first.length > 1) {
             return KeyboardEvent(first) // Got a utf8 char like an emoji
         } else {
@@ -42,11 +51,7 @@ internal class PosixEventParser(
 
         if (ch == ESC) {
             escaped = true
-            try {
-                read()
-            } catch (e: RuntimeException) {
-                return KeyboardEvent("Escape")
-            }
+            read() ?: return KeyboardEvent("Escape")
             if (ch == ESC) {
                 return KeyboardEvent("Escape")
             }
@@ -60,11 +65,11 @@ internal class PosixEventParser(
             if (ch == 'O') {
                 // ESC O letter
                 // ESC O modifier letter
-                read()
+                read() ?: return null
 
                 if (ch in '0'..'9') {
                     modifier = ch.code - 1
-                    read()
+                    read() ?: return null
                 }
 
                 code.append(ch)
@@ -75,12 +80,12 @@ internal class PosixEventParser(
                 // ESC [ [ num char
                 // For mouse events:
                 // ESC [ M byte byte byte
-                read()
+                read() ?: return null
 
                 if (ch == '[') {
                     // escape codes might have a second bracket
                     code.append(ch)
-                    read()
+                    read() ?: return null
                 } else if (ch == 'M') {
                     // mouse event
                     return processMouseEvent(timeout)
@@ -91,16 +96,16 @@ internal class PosixEventParser(
                 // leading digits
                 repeat(3) {
                     if (ch in '0'..'9') {
-                        read()
+                        read() ?: return null
                     }
                 }
 
                 // modifier
                 if (ch == ';') {
-                    read()
+                    read() ?: return null
 
                     if (ch in '0'..'9') {
-                        read()
+                        read() ?: return null
                     }
                 }
 
@@ -342,17 +347,17 @@ internal class PosixEventParser(
         )
     }
 
-    private fun processMouseEvent(timeout: TimeMark): InputEvent {
+    private fun processMouseEvent(timeout: TimeMark): InputEvent? {
         // Mouse event coordinates are raw values, not decimal text, and they're sometimes utf-8
         // encoded to fit larger values.
-        val cb = readUtf8Int(timeout)
-        val cx = readUtf8Int(timeout) - 33
+        val cb = readUtf8Int(timeout) ?: return null
+        val cx = (readUtf8Int(timeout) ?: return null) - 33
         // XXX: I've seen the terminal not send the third byte like `ESC [ M # W`, but I can't find
         // that pattern documented anywhere, so maybe it's an issue with the terminal emulator not
         // encoding utf8 correctly?
-        val cy = runCatching {
-            readUtf8Int(TimeSource.Monotonic.markNow() + 1.milliseconds) - 33
-        }.getOrElse { 0 }
+        val cy = readUtf8Int(TimeSource.Monotonic.markNow() + 1.milliseconds).let {
+            if (it == null) 0 else it - 33
+        }
         val shift = (cb and 4) != 0
         val alt = (cb and 8) != 0
         val ctrl = (cb and 16) != 0
@@ -373,7 +378,7 @@ internal class PosixEventParser(
     }
 
     /** Read one utf-8 encoded codepoint from the input stream. */
-    private fun readUtf8Int(timeout: TimeMark): Int {
+    private fun readUtf8Int(timeout: TimeMark): Int? {
         return readBytesAsUtf8 { readRawByte(timeout) }
     }
 }

mordant/src/commonMain/kotlin/com/github/ajalt/mordant/terminal/terminalinterface/TerminalInterface.posix.kt

@@ -92,7 +92,13 @@ abstract class TerminalInterfacePosix : StandardTerminalInterface() {
     abstract fun setStdinTermios(termios: Termios)
     abstract val termiosConstants: TermiosConstants
     protected abstract fun isatty(fd: Int): Boolean
-    protected abstract fun readRawByte(timeout: TimeMark): Int
+
+    /**
+     * Read a byte from the terminal, or `null` if no byte is available.
+     *
+     * This will only be called while raw mode is active.
+     */
+    protected abstract fun readRawByte(): Int?
 
     override fun stdoutInteractive(): Boolean = isatty(STDOUT_FILENO)
     override fun stdinInteractive(): Boolean = isatty(STDIN_FILENO)
@@ -127,7 +133,7 @@ abstract class TerminalInterfacePosix : StandardTerminalInterface() {
     }
 
     override fun readInputEvent(timeout: TimeMark, mouseTracking: MouseTracking): InputEvent? {
-        return PosixEventParser { t -> readRawByte(t) }.readInputEvent(timeout)
+        return PosixEventParser { readRawByte() }.readInputEvent(timeout)
     }
 }
 

mordant/src/jsCommonMain/kotlin/com/github/ajalt/mordant/terminal/terminalinterface/TerminalInterface.jsCommon.kt

@@ -40,13 +40,8 @@ internal abstract class TerminalInterfaceNode<BufferT> : TerminalInterfaceJsComm
     abstract fun readSync(fd: Int, buffer: BufferT, offset: Int, len: Int): Int
 
     override fun readInputEvent(timeout: TimeMark, mouseTracking: MouseTracking): InputEvent? {
-        return PosixEventParser { t ->
-            val buf = allocBuffer(1)
-            do {
-                val c = readByteWithBuf(buf)?.let { it[0].code }
-                if (c != null) return@PosixEventParser c
-            } while (t.hasNotPassedNow())
-            throw RuntimeException("Timeout reading from stdin (timeout=${timeout.elapsedNow()})")
+        return PosixEventParser {
+            readByteWithBuf(allocBuffer(1))?.let { it[0].code }
         }.readInputEvent(timeout)
     }
 

mordant/src/jvmMain/kotlin/com/github/ajalt/mordant/terminal/terminalinterface/TerminalInterface.jvm.posix.kt

@@ -1,16 +1,10 @@
 package com.github.ajalt.mordant.terminal.terminalinterface
 
-import kotlin.time.TimeMark
-
 /**
  * A base class for terminal interfaces for JVM POSIX systems that uses `System.in` for input.
  */
 abstract class TerminalInterfaceJvmPosix : TerminalInterfacePosix() {
-    override fun readRawByte(timeout: TimeMark): Int {
-        do {
-            val c = System.`in`.read()
-            if (c >= 0) return c
-        } while (timeout.hasNotPassedNow())
-        throw RuntimeException("Timeout reading from stdin (timeout=$timeout)")
+    override fun readRawByte(): Int? {
+        return System.`in`.read().takeUnless { it <= 0 }
     }
 }

mordant/src/posixMain/kotlin/com/github/ajalt/mordant/terminal/terminalinterface/TerminalInterface.native.posix.kt

@@ -4,21 +4,18 @@ import kotlinx.cinterop.ByteVar
 import kotlinx.cinterop.alloc
 import kotlinx.cinterop.memScoped
 import kotlinx.cinterop.value
-import kotlin.time.TimeMark
 
 internal abstract class TerminalInterfaceNativePosix : TerminalInterfacePosix() {
     override fun isatty(fd: Int): Boolean {
         return platform.posix.isatty(fd) != 0
     }
 
-    override fun readRawByte(timeout: TimeMark): Int = memScoped {
-        do {
-            val c = alloc<ByteVar>()
-            val read = readIntoBuffer(c)
-            if (read < 0) throw RuntimeException("Error reading from stdin")
-            if (read > 0) return c.value.toInt()
-        } while (timeout.hasNotPassedNow())
-        throw RuntimeException("Timeout reading from stdin (timeout=$timeout)")
+    override fun readRawByte(): Int? = memScoped {
+        val c = alloc<ByteVar>()
+        val read = readIntoBuffer(c)
+        if (read < 0) throw RuntimeException("Error reading from stdin")
+        if (read > 0) return c.value.toInt()
+        return null
     }
 
     // `read` has different byte widths on linux and apple