Convert FileIoHandler.java to Kotlin (facebook#50612)

Summary:
Pull Request resolved: facebook#50612

Java to Kotlin conversion

Changelog:
[Internal]

Reviewed By: cortinico

Differential Revision: D72742937

fbshipit-source-id: b72b51460555226fa7fe99f4ca5290f46c478291

Author: alanleedev

packages/react-native/ReactAndroid/api/ReactAndroid.api

@@ -3238,9 +3238,9 @@ public abstract interface class com/facebook/react/modules/websocket/WebSocketMo
 	public abstract fun onMessage (Lokio/ByteString;Lcom/facebook/react/bridge/WritableMap;)V
 }
 
-public class com/facebook/react/packagerconnection/FileIoHandler : java/lang/Runnable {
+public final class com/facebook/react/packagerconnection/FileIoHandler : java/lang/Runnable {
 	public fun <init> ()V
-	public fun handlers ()Ljava/util/Map;
+	public final fun handlers ()Ljava/util/Map;
 	public fun run ()V
 }
 

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/packagerconnection/FileIoHandler.java

@@ -0,0 +1,161 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.react.packagerconnection
+
+import android.os.Handler
+import android.os.Looper
+import android.util.Base64
+import com.facebook.common.logging.FLog
+import java.io.FileInputStream
+import java.io.FileNotFoundException
+import java.io.IOException
+import org.json.JSONObject
+
+public class FileIoHandler : Runnable {
+
+  private class TtlFileInputStream(path: String?) {
+    private val stream = FileInputStream(path)
+    private var ttl: Long = System.currentTimeMillis() + FILE_TTL
+
+    private fun extendTtl() {
+      ttl = System.currentTimeMillis() + FILE_TTL
+    }
+
+    fun expiredTtl(): Boolean = System.currentTimeMillis() >= ttl
+
+    @Throws(IOException::class)
+    fun read(size: Int): String {
+      extendTtl()
+      val buffer = ByteArray(size)
+      val bytesRead = stream.read(buffer)
+      return Base64.encodeToString(buffer, 0, bytesRead, Base64.DEFAULT)
+    }
+
+    @Throws(IOException::class)
+    fun close() {
+      stream.close()
+    }
+  }
+
+  private var nextHandle = 1
+  private val handler = Handler(Looper.getMainLooper())
+  private val openFiles: MutableMap<Int, TtlFileInputStream> = mutableMapOf()
+  private val requestHandlers: MutableMap<String, RequestHandler> = mutableMapOf()
+
+  init {
+    requestHandlers["fopen"] =
+        object : RequestOnlyHandler() {
+          override fun onRequest(params: Any?, responder: Responder) {
+            synchronized(openFiles) {
+              try {
+                val paramsObj =
+                    params as JSONObject?
+                        ?: throw Exception(
+                            "params must be an object { mode: string, filename: string }")
+                val mode = paramsObj.optString("mode") ?: throw Exception("missing params.mode")
+                val filename =
+                    paramsObj.optString("filename") ?: throw Exception("missing params.filename")
+                require(mode == "r") { "unsupported mode: $mode" }
+
+                responder.respond(addOpenFile(filename))
+              } catch (e: Exception) {
+                responder.error(e.toString())
+              }
+            }
+          }
+        }
+    requestHandlers["fclose"] =
+        object : RequestOnlyHandler() {
+          override fun onRequest(params: Any?, responder: Responder) {
+            synchronized(openFiles) {
+              try {
+                if (params !is Number) {
+                  throw Exception("params must be a file handle")
+                }
+                val stream =
+                    openFiles[params]
+                        ?: throw Exception("invalid file handle, it might have timed out")
+
+                openFiles.remove(params)
+                stream.close()
+                responder.respond("")
+              } catch (e: Exception) {
+                responder.error(e.toString())
+              }
+            }
+          }
+        }
+    requestHandlers["fread"] =
+        object : RequestOnlyHandler() {
+          override fun onRequest(params: Any?, responder: Responder) {
+            synchronized(openFiles) {
+              try {
+                val paramsObj =
+                    params as JSONObject?
+                        ?: throw Exception(
+                            "params must be an object { file: handle, size: number }")
+                val file = paramsObj.optInt("file")
+                if (file == 0) {
+                  throw Exception("invalid or missing file handle")
+                }
+                val size = paramsObj.optInt("size")
+                if (size == 0) {
+                  throw Exception("invalid or missing read size")
+                }
+                val stream =
+                    openFiles[file]
+                        ?: throw Exception("invalid file handle, it might have timed out")
+
+                responder.respond(stream.read(size))
+              } catch (e: Exception) {
+                responder.error(e.toString())
+              }
+            }
+          }
+        }
+  }
+
+  public fun handlers(): Map<String, RequestHandler> = requestHandlers
+
+  @Throws(FileNotFoundException::class)
+  private fun addOpenFile(filename: String): Int {
+    val handle = nextHandle++
+    openFiles[handle] = TtlFileInputStream(filename)
+    if (openFiles.size == 1) {
+      handler.postDelayed(this@FileIoHandler, FILE_TTL)
+    }
+    return handle
+  }
+
+  override fun run() {
+    // clean up files that are past their expiry date
+    synchronized(openFiles) {
+      openFiles.entries.removeAll { (_, stream) ->
+        if (stream.expiredTtl()) {
+          try {
+            stream.close()
+          } catch (e: IOException) {
+            FLog.e(TAG, "Failed to close expired file", e)
+          }
+          true
+        } else {
+          false
+        }
+      }
+
+      if (openFiles.isNotEmpty()) {
+        handler.postDelayed(this, FILE_TTL)
+      }
+    }
+  }
+
+  private companion object {
+    private val TAG: String = JSPackagerClient::class.java.simpleName
+    private const val FILE_TTL = 30_000L
+  }
+}