Move FileUtils to file package and define more file util functions

A lot of utils have been defined now that can be used to safely manage files.

The java java.io.File API has poor support for detecting symlinks including broken symlinks. Android implementation also has issues. Check FileTypes.getFileType() function for more info. For this reason, the UnixFileAttributes and related classes has been ported from AOSP to get file attributes and type.

Some file utils and android versions use google's Guava com.google.common.io.MoreFiles library for managing files, specially for safer directory deletion with SecureDirectoryStream.

Some file utils and android versions use org.apache.commons.io.FileUtils for managing files. The library version used is 2.5 and it must not be incremented for compatibility with android version < 8, otherwise runtime crashes will occur.

Author: agnostic-apollo

app/build.gradle

@@ -9,18 +9,22 @@ android {
     ndkVersion project.properties.ndkVersion
 
     dependencies {
-        implementation "androidx.annotation:annotation:1.1.0"
-        implementation 'androidx.appcompat:appcompat:1.2.0'
-        implementation 'androidx.core:core:1.5.0-beta03'
+        implementation "androidx.annotation:annotation:1.2.0"
+        implementation "androidx.core:core:1.5.0-rc01"
         implementation "androidx.drawerlayout:drawerlayout:1.1.1"
-        implementation 'androidx.preference:preference:1.1.1'
+        implementation "androidx.preference:preference:1.1.1"
         implementation "androidx.viewpager:viewpager:1.0.0"
-        implementation 'com.google.guava:guava:24.1-jre'
-        implementation  "io.noties.markwon:core:$markwon_version"
-        implementation  "io.noties.markwon:ext-strikethrough:$markwon_version"
-        implementation  "io.noties.markwon:linkify:$markwon_version"
-        implementation  "io.noties.markwon:recycler:$markwon_version"
+        implementation "com.google.guava:guava:24.1-jre"
+        implementation "io.noties.markwon:core:$markwon_version"
+        implementation "io.noties.markwon:ext-strikethrough:$markwon_version"
+        implementation "io.noties.markwon:linkify:$markwon_version"
+        implementation "io.noties.markwon:recycler:$markwon_version"
         implementation project(":terminal-view")
+
+        // Do not increment version higher than 2.5 or there
+        // will be runtime exceptions on android < 8
+        // due to missing classes like java.nio.file.Path.
+        implementation "commons-io:commons-io:2.5"
     }
 
     defaultConfig {
@@ -95,10 +99,8 @@ android {
 }
 
 dependencies {
-    implementation 'androidx.appcompat:appcompat:1.2.0'
-    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
-    testImplementation 'junit:junit:4.13.1'
-    testImplementation 'org.robolectric:robolectric:4.4'
+    testImplementation "junit:junit:4.13.1"
+    testImplementation "org.robolectric:robolectric:4.4"
 }
 
 task versionName {

app/src/main/java/com/termux/app/RunCommandService.java

@@ -14,7 +14,7 @@
 import com.termux.R;
 import com.termux.app.TermuxConstants.TERMUX_APP.RUN_COMMAND_SERVICE;
 import com.termux.app.TermuxConstants.TERMUX_APP.TERMUX_SERVICE;
-import com.termux.app.utils.FileUtils;
+import com.termux.app.file.FileUtils;
 import com.termux.app.utils.Logger;
 import com.termux.app.utils.NotificationUtils;
 import com.termux.app.utils.PluginUtils;
@@ -354,9 +354,9 @@ public int onStartCommand(Intent intent, int flags, int startId) {
 
         // If executable is not a regular file, or is not readable or executable, then just return
         // Setting of missing read and execute permissions is not done
-        errmsg = FileUtils.validateRegularFileExistenceAndPermissions(this, executionCommand.executable,
-            null, PluginUtils.PLUGIN_EXECUTABLE_FILE_PERMISSIONS,
-            false, false);
+        errmsg = FileUtils.validateRegularFileExistenceAndPermissions(this, "executable", executionCommand.executable, null,
+            PluginUtils.PLUGIN_EXECUTABLE_FILE_PERMISSIONS, true, true,
+            false);
         if (errmsg != null) {
             errmsg  += "\n" + this.getString(R.string.msg_executable_absolute_path, executionCommand.executable);
             executionCommand.setStateFailed(ExecutionCommand.RESULT_CODE_FAILED, errmsg, null);
@@ -376,10 +376,9 @@ public int onStartCommand(Intent intent, int flags, int startId) {
             // under {@link TermuxConstants#TERMUX_FILES_DIR_PATH}
             // We try to set execute permissions, but ignore if they are missing, since only read and write permissions are required
             // for working directories.
-            errmsg = FileUtils.validateDirectoryExistenceAndPermissions(this, executionCommand.workingDirectory,
-                TermuxConstants.TERMUX_FILES_DIR_PATH, PluginUtils.PLUGIN_WORKING_DIRECTORY_PERMISSIONS,
-                true, true, false,
-                true);
+            errmsg = FileUtils.validateDirectoryFileExistenceAndPermissions(this, "working", executionCommand.workingDirectory, TermuxConstants.TERMUX_FILES_DIR_PATH, true,
+                PluginUtils.PLUGIN_WORKING_DIRECTORY_PERMISSIONS, true, true,
+                true, true);
             if (errmsg != null) {
                 errmsg  += "\n" + this.getString(R.string.msg_working_directory_absolute_path, executionCommand.workingDirectory);
                 executionCommand.setStateFailed(ExecutionCommand.RESULT_CODE_FAILED, errmsg, null);