Add ExternalImageAndroid.kt

mirai-core/src/androidMain/kotlin/net/mamoe/mirai/utils/ExternalImageAndroid.kt

+@file:Suppress("EXPERIMENTAL_API_USAGE")
+
+package net.mamoe.mirai.utils
+
+import android.graphics.BitmapFactory
+import io.ktor.util.asStream
+import kotlinx.coroutines.Dispatchers.IO
+import kotlinx.coroutines.withContext
+import kotlinx.io.core.Input
+import kotlinx.io.core.IoBuffer
+import kotlinx.io.core.copyTo
+import kotlinx.io.errors.IOException
+import kotlinx.io.streams.asInput
+import kotlinx.io.streams.asOutput
+import java.io.File
+import java.io.InputStream
+import java.net.URL
+
+/*
+ * 将各类型图片容器转为 [ExternalImage]
+ */
+
+/**
+ * 读取文件头识别图片属性, 然后构造 [ExternalImage]
+ */
+@Throws(IOException::class)
+fun File.toExternalImage(): ExternalImage {
+    val input = BitmapFactory.decodeFile(this.absolutePath)
+    checkNotNull(input) { "Unable to read file(path=${this.path}), BitmapFactory.decodeFile returned null" }
+
+    return ExternalImage(
+        width = input.width,
+        height = input.height,
+        md5 = this.inputStream().use { it.md5() },
+        imageFormat = this.nameWithoutExtension,
+        input = this.inputStream().asInput(IoBuffer.Pool),
+        inputSize = this.length()
+    )
+}
+
+/**
+ * 在 [IO] 中进行 [File.toExternalImage]
+ */
+@Suppress("unused")
+suspend fun File.suspendToExternalImage(): ExternalImage = withContext(IO) { toExternalImage() }
+
+/**
+ * 下载文件到临时目录然后调用 [File.toExternalImage]
+ */
+@Throws(IOException::class)
+fun URL.toExternalImage(): ExternalImage {
+    val file = createTempFile().apply { deleteOnExit() }
+    file.outputStream().asOutput().use { output ->
+        openStream().asInput().use { input ->
+            input.copyTo(output)
+        }
+    }
+    return file.toExternalImage()
+}
+
+/**
+ * 在 [IO] 中进行 [URL.toExternalImage]
+ */
+@Suppress("unused")
+suspend fun URL.suspendToExternalImage(): ExternalImage = withContext(IO) { toExternalImage() }
+
+/**
+ * 保存为临时文件然后调用 [File.toExternalImage]
+ */
+@Throws(IOException::class)
+fun InputStream.toExternalImage(): ExternalImage {
+    val file = createTempFile().apply { deleteOnExit() }
+    file.outputStream().asOutput().use {
+        this.asInput().copyTo(it)
+    }
+    this.close()
+    return file.toExternalImage()
+}
+
+/**
+ * 在 [IO] 中进行 [InputStream.toExternalImage]
+ */
+@Suppress("unused")
+suspend fun InputStream.suspendToExternalImage(): ExternalImage = withContext(IO) { toExternalImage() }
+
+/**
+ * 保存为临时文件然后调用 [File.toExternalImage]
+ */
+@Throws(IOException::class)
+fun Input.toExternalImage(): ExternalImage {
+    val file = createTempFile().apply { deleteOnExit() }
+    file.outputStream().asOutput().use {
+        this.asStream().asInput().copyTo(it)
+    }
+    return file.toExternalImage()
+}
+
+/**
+ * 在 [IO] 中进行 [Input.toExternalImage]
+ */
+@Suppress("unused")
+suspend fun Input.suspendToExternalImage(): ExternalImage = withContext(IO) { toExternalImage() }