chore: implement some IO utilities

src/main/kotlin/io/gitlab/jfronny/sdom/ui/ByteVirtualFile.kt

@@ -0,0 +1,21 @@
+package io.gitlab.jfronny.sdom.ui
+
+import com.intellij.openapi.fileTypes.FileType
+import com.intellij.testFramework.LightVirtualFileBase
+import com.intellij.util.LocalTimeCounter
+import java.io.ByteArrayInputStream
+import java.io.ByteArrayOutputStream
+import java.io.InputStream
+import java.io.OutputStream
+
+class ByteVirtualFile(name: String, fileType: FileType?, modificationStamp: Long, private val content: ByteArray) : LightVirtualFileBase(name, fileType, modificationStamp) {
+    constructor() : this("")
+    constructor(name: String) : this(name, ByteArray(0))
+    constructor(name: String, content: ByteArray) : this(name, null, LocalTimeCounter.currentTime(), content)
+    constructor(name: String, fileType: FileType?, content: ByteArray) : this(name, fileType, LocalTimeCounter.currentTime(), content)
+
+    override fun getOutputStream(requestor: Any?, newModificationStamp: Long, newTimeStamp: Long): OutputStream = ByteArrayOutputStream()
+    override fun contentsToByteArray(): ByteArray = this.content.copyOf()
+    override fun getInputStream(): InputStream = ByteArrayInputStream(content)
+    override fun getLength(): Long = content.size.toLong()
+}

src/main/kotlin/io/gitlab/jfronny/sdom/util/OSUtils.kt

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+package io.gitlab.jfronny.sdom.util
+
+import java.awt.Desktop
+import java.io.File
+import java.nio.file.Files
+import java.nio.file.Path
+import java.nio.file.Paths
+import java.util.regex.Pattern
+import java.util.stream.Stream
+
+object OSUtils {
+    var TYPE: Type? = System.getProperty("os.name", "generic").lowercase().let { os ->
+        if ((os.contains("mac")) || (os.contains("darwin"))) {
+            Type.MAC_OS
+        } else if (os.contains("win")) {
+            Type.WINDOWS
+        } else if (os.contains("nux")) {
+            Type.LINUX
+        } else {
+            null // probably fine :)
+        }
+    }
+
+    fun executablePathContains(executableName: String): Boolean {
+        return try {
+            Stream.of(
+                *System.getenv("PATH").split(Pattern.quote(File.pathSeparator).toRegex()).dropLastWhile { it.isEmpty() }
+                    .toTypedArray())
+                .map { path: String -> path.replace("\"", "") }
+                .map { first: String -> Paths.get(first) }
+                .anyMatch { path: Path ->
+                    (Files.exists(path.resolve(executableName))
+                            && Files.isExecutable(path.resolve(executableName)))
+                }
+        } catch (e: Exception) {
+            false
+        }
+    }
+
+    fun openFile(path: File) {
+        if (OSUtils.TYPE === OSUtils.Type.LINUX && OSUtils.executablePathContains("xdg-open")) {
+            Runtime.getRuntime().exec(arrayOf("xdg-open", path.absolutePath))
+        } else if (Desktop.isDesktopSupported() && Desktop.getDesktop().isSupported(Desktop.Action.BROWSE)) {
+            Desktop.getDesktop().open(path)
+        }
+    }
+
+    enum class Type {
+        WINDOWS, MAC_OS, LINUX
+    }
+}