1 files changed, 76 insertions, 29 deletions

diff --git a/src/main/kotlin/WebOS.kt b/src/main/kotlin/WebOS.kt
index d1b0d81..6fe4ceb 100644
--- a/src/main/kotlin/WebOS.kt
+++ b/src/main/kotlin/WebOS.kt
@@ -16,7 +16,6 @@ fun main() {
 
 data class CharacterRun(val text: String, val color: String)
 
-
 abstract class Activity(val console: Console) {
 	abstract fun render(columns: Int, rows: Int): List<List<CharacterRun>>
 }
@@ -30,6 +29,16 @@ class Console(val os: WebOS, val renderElement: Element?) {
 
 	var shouldRerender = true
 
+	lateinit var currentUser: User
+
+	private var _workingDirectory: AbsolutPath? = null
+
+	var workingDirectory: AbsolutPath
+		get() {
+			if (_workingDirectory == null) _workingDirectory = currentUser.homeDirectory; return _workingDirectory!!
+		}
+		set(value) { _workingDirectory = value }
+
 	fun openActivity(activity: Activity) {
 		activityStack.addLast(activity)
 		invalidateRender()
@@ -58,45 +67,84 @@ class Console(val os: WebOS, val renderElement: Element?) {
 class WebOS {
 	private val _consoles = mutableListOf<Console>()
 	val consoles get() = _consoles.toList()
-	val fileSystem = FileSystem()
+	val IOHandler = IOHandler()
 	fun registerConsole(element: Element) {
 		_consoles.add(Console(this, element))
 	}
 }
 
-interface User {
-	val name: String
-	val homeDirectory: Path
+data class User(
+	val name: String,
+	val homeDirectory: AbsolutPath
+)
+
+data class RelativePath internal constructor(override val parts: List<String>) : Path {
+	override fun toAbsolutPath(context: Console): AbsolutPath {
+		val result = mutableListOf<String>()
+		for (part in parts) {
+			when (part) {
+				"." -> result.addAll(context.workingDirectory.parts)
+				"~" -> result.addAll(context.currentUser.homeDirectory.parts)
+				".." -> { result.removeLast() }
+				else -> result.add(part)
+			}
+		}
+		return AbsolutPath(result)
+	}
+}
+
+data class AbsolutPath internal constructor(override val parts: List<String>) : Path {
+	override fun toAbsolutPath(context: Console): AbsolutPath = this
 }
 
-data class Path private constructor(val parts: List<String>) {
+sealed interface Path {
+	val parts: List<String>
+	fun toAbsolutPath(context: Console): AbsolutPath
 	companion object {
-		fun of(text: String) =
-			Path(text.split("/"))
-		fun of(vararg parts: String): Path {
-			if(parts.any { it.contains("/") })
-				throw IllegalArgumentException("Path parts cannot contain forward slashes")
-			return Path(parts.toList())
+		fun of(string: String): Path {
+			val isAbsolut = string.first() == '/'
+			val parts = string.split("/")
+			val aparts = parts.subList(1, parts.size)
+			if (aparts.contains(".") || aparts.contains("~"))
+				throw IllegalArgumentException("'.' and '~' are only allowed at the beginning of a relative path")
+			if (!isAbsolut) return RelativePath(parts)
+			if (aparts.contains("..")) throw IllegalArgumentException("'..' is only allowed in a relative path")
+			return AbsolutPath(aparts)
 		}
 	}
 }
 
 class FileSystem {
-	val mounts = mutableMapOf<Path, Mount>()
-	fun mount(path: Path, mount:Mount) {
-		mounts[path] = mount
+	fun read(relativePath: Path): ReadResult = TODO()
+	fun write(path: Path, data: ByteArray): Unit = TODO()
+	fun stat(path: Path): Unit = TODO()
+}
+
+class IOHandler {
+	val mounts = mutableListOf<Mount>()
+	fun mount(absolutPath: AbsolutPath, fileSystem: FileSystem) {
+		mounts += Mount(absolutPath, fileSystem)
+	}
+	fun unmount(mountPoint: AbsolutPath) {
+		mounts.removeAll { it.mountPoint == mountPoint }
 	}
-	fun <T>findMountFor(path: Path, operation: Mount.(relativePath: Path) -> T) :T{
-		val (mountPath, mount) = mounts.filterKeys {
-			// path.startsWith(it)
-			true
-		}.maxByOrNull { it.key.parts.size} ?: throw IllegalStateException("No mount present")
-		return mount.operation(mountPath.relativize(path))
+	fun <T> findMountFor(context: Console, path: Path, operation: FileSystem.(relativePath: Path) -> T): T {
+		val absolutPath = path.toAbsolutPath(context)
+		val mount = mounts.filter {
+			var result = true
+			it.mountPoint.parts.forEachIndexed { index, part -> if (absolutPath.parts[index] != part) {
+				result = false
+			} }
+			result
+		}.maxByOrNull { it.mountPoint.parts.size} ?: throw IllegalStateException("No mount present")
+		return mount.fileSystem.operation(
+			AbsolutPath(absolutPath.parts.subList(mount.mountPoint.parts.size, absolutPath.parts.size))
+		)
 	}
 
-	fun read(path: Path): ReadResult = findMountFor(path) { read(it) }
-	fun write(path: Path, data: ByteArray): Unit = TODO()
-	fun stat(path: Path): Unit = TODO()
+	fun read(context: Console, path: Path): ReadResult = findMountFor(context, path) { read(it) }
+	fun write(context: Console, path: Path, data: ByteArray): Unit = findMountFor(context, path) { write(it, data) }
+	fun stat(context: Console, path: Path): Unit = findMountFor(context, path) { stat(it) }
 }
 
 sealed class ReadResult {
@@ -104,11 +152,10 @@ sealed class ReadResult {
 	object NotFound
 	object NoAccess
 }
-interface Mount {
-	fun read(relativePath: Path): ReadResult = TODO()
-	fun write(path: Path, data: ByteArray): Unit = TODO()
-	fun stat(path: Path): Unit = TODO()
-}
+data class Mount (
+	val mountPoint: AbsolutPath,
+	val fileSystem: FileSystem
+)
 
 data class Stat(
 	val exists: Boolean,