feat: Filetree API

app/src/androidTest/java/be/re/writand/ExampleInstrumentedTest.kt

@@ -3,10 +3,10 @@ package be.re.writand
 import androidx.test.platform.app.InstrumentationRegistry
 import androidx.test.ext.junit.runners.AndroidJUnit4
 
-import org.junit.Test
 import org.junit.runner.RunWith
 
 import org.junit.Assert.*
+import org.junit.Test
 
 /**
  * Instrumented test, which will execute on an Android device.

app/src/main/java/be/re/writand/data/local/FileManagerLocal.kt

@@ -0,0 +1,86 @@
+package be.re.writand.data.local
+
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import java.io.File
+import java.nio.file.Files
+import java.nio.file.NotDirectoryException
+import java.nio.file.Path
+import java.nio.file.Paths
+import java.util.PriorityQueue
+import java.util.Queue
+import kotlin.io.path.deleteExisting
+import kotlin.io.path.exists
+import kotlin.io.path.isDirectory
+import kotlin.io.path.name
+
+class FileManagerLocal : IFileManager {
+
+    /**
+     * Checks if a directory is empty.
+     * Requires API 26!
+     *
+     * @param[path] The path of the directory to be checked.
+     * @return returns true if the directory is empty. If [path] points to a file,
+     * false is immediately returned.
+     */
+    fun isDirectoryEmpty(path: Path): Boolean {
+        if (!path.isDirectory()) return false
+        return Files.list(path).count() == 0L
+    }
+
+    override suspend fun create(name: String, basePath: Path) {
+        if (!basePath.isDirectory()) throw NotDirectoryException(basePath.name)
+
+        val fullPath = Paths.get(basePath.toString(), name)
+        withContext(Dispatchers.IO) {
+            val res = fullPath.toFile().createNewFile()
+            if (!res) throw FileAlreadyExistsException(
+                fullPath.toFile(),
+                reason = "File already exists."
+            )
+        }
+    }
+
+    override suspend fun delete(path: Path) {
+        // path is a directory and is not empty, delete everything in this directory
+        if (path.isDirectory() && !isDirectoryEmpty(path)) {
+            val queue: Queue<Path> = PriorityQueue()
+            queue.add(path)
+
+            while (!queue.isEmpty()) {
+                val top = queue.poll()!!
+                if (top.isDirectory() && !isDirectoryEmpty(top)) {
+
+                    // add all the elements of the current directory to the queue
+                    for (dir in top.iterator()) {
+                        queue.add(dir)
+                    }
+
+                    // add the directory back into the queue (top is not an empty directory)
+                    queue.add(top)
+                } else {
+
+                    // top is a file or an empty directory
+                    top.deleteExisting()
+                }
+            }
+        } else {
+            path.deleteExisting()
+        }
+    }
+
+    override suspend fun move(from: Path, to: Path) {
+        withContext(Dispatchers.IO) {
+            Files.move(from, to)
+        }
+    }
+
+    override suspend fun rename(path: Path, newName: String) {
+        move(path, Paths.get(path.parent.toString(), newName))
+    }
+
+    override suspend fun walk(root: Path): FileTreeWalk {
+        return File(root.toUri()).walkTopDown()
+    }
+}

app/src/main/java/be/re/writand/data/local/IFileManager.kt

@@ -0,0 +1,64 @@
+package be.re.writand.data.local
+
+import java.nio.file.Path
+import java.nio.file.InvalidPathException
+import java.nio.file.NotDirectoryException
+import java.io.IOException
+import java.io.IOError
+
+/**
+ * An interface to handle the File trees.
+ * File is used to mention both real files and directories at the same time.
+ */
+interface IFileManager {
+    /**
+    * Create a new File.
+    * @param[name] the name of the new File.
+     * @param[basePath] the path where the new File should be created in.
+     * @throws InvalidPathException
+     * @throws FileAlreadyExistsException
+     * @throws NotDirectoryException
+     * @throws IOException
+     * @throws SecurityException
+    * */
+    suspend fun create(name: String, basePath: Path)
+
+    /**
+     * Delete a File.
+     * Symbolic links are followed.
+     * @param[path] the path pointing to the File to be deleted.
+     * @throws NoSuchFileException
+     */
+    suspend fun delete(path: Path)
+
+    /**
+     * Move a File to a different location.
+     * If the File to be moved is a symbolic link, then the link itself is moved instead of the
+     * target of the link.
+     * @param[from] the start location.
+     * @param[to] the destination.
+     * @throws FileAlreadyExistsException
+     * @throws IOException
+     * @throws SecurityException
+     */
+    suspend fun move(from: Path, to: Path)
+
+    /**
+     * Rename a file to a new name
+     * @param[path] the path to the File to rename
+     * @param[newName] the new name to be given to [path]
+     * @throws FileAlreadyExistsException
+     * @throws IOException
+     * @throws SecurityException
+     */
+    suspend fun rename(path: Path, newName: String)
+
+    /**
+     * Walk the directory and build a File tree.
+     * @throws NullPointerException
+     * @throws IllegalArgumentException
+     * @throws IOError
+     * @throws SecurityException
+     */
+    suspend fun walk(root: Path): FileTreeWalk
+}

app/src/test/java/be/re/writand/ExampleUnitTest.kt

@@ -1,17 +0,0 @@
-package be.re.writand
-
-import org.junit.Test
-
-import org.junit.Assert.*
-
-/**
- * Example local unit test, which will execute on the development machine (host).
- *
- * See [testing documentation](http://d.android.com/tools/testing).
- */
-class ExampleUnitTest {
-    @Test
-    fun addition_isCorrect() {
-        assertEquals(4, 2 + 2)
-    }
-}

app/src/test/java/be/re/writand/FileManagerLocalTest.kt

@@ -0,0 +1,70 @@
+package be.re.writand
+
+import android.annotation.SuppressLint
+import be.re.writand.data.local.FileManagerLocal
+import org.junit.jupiter.api.Assertions.assertFalse
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.BeforeAll
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+import org.mockito.Mock
+import org.mockito.Mockito.mockStatic
+import org.mockito.MockitoAnnotations
+import org.mockito.kotlin.any
+import org.mockito.kotlin.whenever
+import java.nio.file.FileSystem
+import java.nio.file.Files
+import java.nio.file.Path
+import java.nio.file.spi.FileSystemProvider
+import java.util.stream.Stream
+import kotlin.io.path.isDirectory
+
+/**
+ * The class containing all the tests for [FileManagerLocal].
+ */
+class FileManagerLocalTest {
+    private lateinit var fileManager: FileManagerLocal
+
+    @Mock
+    private lateinit var path: Path
+
+    @Mock
+    private lateinit var provider: FileSystemProvider
+
+    @Mock
+    private lateinit var fileSystem: FileSystem
+
+    @BeforeEach
+    fun setup() {
+        fileManager = FileManagerLocal()
+        MockitoAnnotations.openMocks(this)
+    }
+
+    companion object {
+        @SuppressLint("CheckResult")
+        @JvmStatic
+        @BeforeAll
+        fun setupStatic(): Unit {
+            mockStatic(Files::class.java)
+        }
+    }
+
+    @SuppressLint("CheckResult")
+    @Test
+    fun testIsDirectoryEmptySuccess() {
+        whenever(fileSystem.provider()).thenReturn(provider)
+        whenever(path.fileSystem).thenReturn(fileSystem)
+        whenever(Files.list(any())).thenReturn(Stream.empty())
+        whenever(path.isDirectory()).thenReturn(true)
+        assertTrue(fileManager.isDirectoryEmpty(path))
+    }
+
+    @Test
+    fun testIsDirectoryNotEmptySuccess() {
+        whenever(fileSystem.provider()).thenReturn(provider)
+        whenever(path.fileSystem).thenReturn(fileSystem)
+        whenever(Files.list(any())).thenReturn(Stream.of(path))
+        whenever(path.isDirectory()).thenReturn(true)
+        assertFalse(fileManager.isDirectoryEmpty(path))
+    }
+}