Add contents to file object, Echo command implementation

Author: geektimus

filesystem/src/main/scala/com/codingmaniacs/scala/exercises/fs/commands/Command.scala

@@ -35,6 +35,7 @@ object Command {
   val TOUCH = "touch"
   val CD = "cd"
   val RM = "rm"
+  val ECHO = "echo"
 
   def emptyCommand: Command = new Command {
     override def apply(state: State): State = state
@@ -77,6 +78,12 @@ object Command {
       } else {
         new Rm(tokens(1))
       }
+    } else if (ECHO.equals(tokens(0))) {
+      if (tokens.length < 2) {
+        incompleteCommand(ECHO)
+      } else {
+        new Echo(tokens.tail)
+      }
     } else {
       new UnknownCommand
     }

filesystem/src/main/scala/com/codingmaniacs/scala/exercises/fs/commands/Echo.scala

@@ -0,0 +1,110 @@
+/*
+ * Copyright (c) 2019 Geektimus
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package com.codingmaniacs.scala.exercises.fs.commands
+
+import com.codingmaniacs.scala.exercises.fs.State
+import com.codingmaniacs.scala.exercises.fs.directories.Directory
+import com.codingmaniacs.scala.exercises.fs.files.File
+
+import scala.annotation.tailrec
+
+class Echo(items: Array[String]) extends Command {
+
+  def createContent(items: Array[String], topIndex: Int): String = {
+
+    @tailrec
+    def createContentRec(currIdx: Int, acc: String): String =
+      currIdx match {
+        case i if i >= topIndex => acc
+        case i => createContentRec(i + 1, acc + items(currIdx))
+      }
+
+    createContentRec(0, "")
+  }
+
+  def getRootAfterEcho(
+    currentDir: Directory,
+    path: List[String],
+    contents: String,
+    append: Boolean
+  ): Directory =
+    if (path.isEmpty) {
+      currentDir
+    } else if (path.tail.isEmpty) {
+      val dirEntry = currentDir.findEntry(path.head)
+      if (dirEntry == null) {
+        currentDir.addEntry(new File(currentDir.path, path.head, contents))
+      } else if (dirEntry.isDirectory) {
+        currentDir
+      } else {
+        if (append) {
+          currentDir.replaceEntry(path.head, dirEntry.asFile.appendContents(contents))
+        } else {
+          currentDir.replaceEntry(path.head, dirEntry.asFile.setContents(contents))
+        }
+      }
+    } else {
+      val nextDir = currentDir.findEntry(path.head).asDirectory
+      val newNextDir = getRootAfterEcho(nextDir, path.tail, contents, append)
+
+      if (newNextDir == nextDir) {
+        currentDir
+      } else {
+        currentDir.replaceEntry(path.head, newNextDir)
+      }
+    }
+
+  def doEcho(state: State, contents: String, filename: String, append: Boolean): State =
+    if (filename.contains(Directory.SEPARATOR)) {
+      state.setMessage("Echo: Filename must not contain separators")
+    } else {
+      val newRoot: Directory = getRootAfterEcho(
+        state.root,
+        state.workingDir.getAllFoldersInPath :+ filename,
+        contents,
+        append
+      )
+      if (newRoot == state.root) {
+        state.setMessage(s"$filename: no such file")
+      } else {
+        State(newRoot, newRoot.findDescendant(state.workingDir.getAllFoldersInPath))
+      }
+    }
+
+  override def apply(state: State): State =
+    if (items.isEmpty) {
+      state
+    } else if (items.size == 1) {
+      state.setMessage(items(0))
+    } else {
+      val op = items(items.length - 2)
+      val filename = items(items.length - 1)
+      val contents = createContent(items, items.length - 2)
+      if (">>".equals(op)) {
+        doEcho(state, contents, filename, append = true)
+      } else if (">".equals(op)) {
+        doEcho(state, contents, filename, append = false)
+      } else {
+        state.setMessage(createContent(items, items.length))
+      }
+    }
+}

filesystem/src/main/scala/com/codingmaniacs/scala/exercises/fs/directories/Directory.scala

@@ -59,8 +59,8 @@ class Directory(
     findEntryHelper(entryName, contents)
   }
 
-  def replaceEntry(entryName: String, newEntry: Directory): Directory =
-    new Directory(parentPath, name, contents.filter(p => !p.name.equals(entryName)) :+ newEntry)
+  def replaceEntry(entryName: String, newEntry: DirEntry): Directory =
+    new Directory(parentPath, name, contents.filter(e => !e.name.equals(entryName)) :+ newEntry)
 
   def isRoot: Boolean = parentPath.isEmpty
 

filesystem/src/main/scala/com/codingmaniacs/scala/exercises/fs/files/File.scala

@@ -23,7 +23,7 @@ package com.codingmaniacs.scala.exercises.fs.files
 
 import com.codingmaniacs.scala.exercises.fs.directories.{ DirEntry, Directory }
 
-class File(override val parentPath: String, override val name: String)
+class File(override val parentPath: String, override val name: String, val contents: String)
     extends DirEntry(parentPath, name) {
   override def asDirectory: Directory =
     throw new FileSystemException("A file cannot be converted to a directory!")
@@ -34,10 +34,17 @@ class File(override val parentPath: String, override val name: String)
 
   override def isDirectory: Boolean = false
   override def isFile: Boolean = !isDirectory
+
+  def setContents(newContents: String): File =
+    new File(parentPath, name, newContents)
+
+  def appendContents(newContents: String): File =
+    setContents(contents + "\n" + newContents)
+
 }
 
 object File {
 
   def empty(parentPath: String, name: String): File =
-    new File(parentPath, name)
+    new File(parentPath, name, "")
 }