rapid-delete-lib 0.3.1

/*
  Copyright 2025 Adam Sweeney

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
*/

// NOTICE
// Modified from turbo-delete (https://github.com/suptejas/turbo-delete)
// Licensed under Apache-2.0
// Changes: refactored for library use

/*
  Copyright 2022 Tejas Ravishankar

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
*/

//! A library for fast, parallel directory deletion with permission handling.
//!
//! This library provides functionality to recursively delete directories,
//! automatically handling read-only files and permission issues that might
//! prevent deletion.

#[cfg(feature = "progressbar")]
use indicatif::ProgressBar;
use jwalk::DirEntry;
use rayon::iter::{IntoParallelRefIterator, ParallelBridge, ParallelIterator};
use rusty_pool::ThreadPool;
use std::{
    collections::BTreeMap,
    path::{Path, PathBuf},
};
use thiserror::Error;

#[derive(Error, Debug)]
pub enum RdError {
    #[error("Failed to read metadata for {0}: {1}")]
    MetadataError(PathBuf, std::io::Error),

    #[error("Failed to set permissions for: {0}: {1}")]
    PermissionError(PathBuf, std::io::Error),

    #[error("Failed to remove item {0}: {1}")]
    RemoveError(PathBuf, std::io::Error),

    #[error("Failed to walk directory: {0}: {1}")]
    WalkdirError(PathBuf, String),

    #[error("IO error: {0}")]
    Io(#[from] std::io::Error),
}

impl From<RdError> for std::io::Error {
    fn from(err: RdError) -> Self {
        match err {
            RdError::Io(e) => e,
            RdError::MetadataError(_, e) => e,
            RdError::PermissionError(_, e) => e,
            RdError::RemoveError(_, e) => e,
            RdError::WalkdirError(path, msg) => std::io::Error::new(
                std::io::ErrorKind::Other,
                format!("Failed to walk directory {}: {}", path.display(), msg),
            ),
        }
    }
}

/// Makes a file or directory writable by removing the read-only flag.
///
/// # Arguments
///
/// * `path` - The path to the file or directory to make writable
///
/// # Errors
///
/// Returns an error if:
/// * The metadata cannot be read
/// * The permissions cannot be set
fn set_writable(path: &Path) -> Result<(), RdError> {
    let mut perms = std::fs::metadata(path)
        .map_err(|err| RdError::MetadataError(path.to_path_buf(), err))?
        .permissions();

    perms.set_readonly(false);
    std::fs::set_permissions(path, perms)
        .map_err(|err| RdError::PermissionError(path.to_path_buf(), err))?;

    Ok(())
}

/// Recursively makes all files in a directory writable.
///
/// This function walks through all files in the given directory (following symlinks)
/// and removes the read-only flag from each file in parallel.
///
/// # Arguments
///
/// * `path` - The root directory path to process
///
/// # Errors
///
/// Returns an error if:
/// * The directory walk fails
/// * Any file's permissions cannot be modified
fn set_folder_writable(path: &Path) -> Result<(), RdError> {
    let entries: Vec<DirEntry<((), ())>> = jwalk::WalkDir::new(&path)
        .skip_hidden(false)
        .into_iter()
        .filter_map(|i| match i {
            Ok(entry) if entry.file_type().is_file() => Some(Ok(entry)),
            Ok(_) => None,
            Err(e) => Some(Err(e)),
        })
        .collect::<Result<Vec<_>, _>>()
        .map_err(|err| RdError::WalkdirError(path.to_path_buf(), err.to_string()))?;

    let errors: Vec<_> = entries
        .par_iter()
        .filter_map(|entry| set_writable(&entry.path()).err())
        .collect();

    if let Some(err) = errors.into_iter().next() {
        return Err(err);
    }

    Ok(())
}

/// Deletes a directory and all its contents in parallel.
///
/// This function performs a fast, parallel deletion of a directory by:
/// 1. Walking the directory tree to catalog all subdirectories by depth
/// 2. Deleting directories in parallel, starting from the deepest level
/// 3. If deletion fails, attempting to fix permission issues and retrying
///
/// The parallel approach significantly speeds up deletion of large directory trees.
///
/// # Arguments
///
/// * `dpath` - The path to the directory to delete
///
/// # Errors
///
/// Returns an error if:
/// * The directory walk fails
/// * Permissions cannot be fixed
/// * The final deletion attempt fails
///
/// # Examples
///
/// ```no_run
/// use std::path::PathBuf;
/// # use rapid_delete::delete_folder;
///
/// let path = PathBuf::from("/tmp/test_dir");
/// delete_folder(&path)?;
/// # Ok::<(), Box<dyn std::error::Error>>(())
/// ```
pub fn delete_folder(dpath: &Path) -> Result<(), RdError> {
    let mut tree: BTreeMap<u64, Vec<PathBuf>> = BTreeMap::new();

    let entries: Vec<DirEntry<((), ())>> = jwalk::WalkDir::new(&dpath)
        .skip_hidden(false)
        .into_iter()
        .par_bridge()
        .filter_map(|i| match i {
            Ok(entry) if entry.path().is_dir() => Some(Ok(entry)),
            Ok(_) => None,
            Err(e) => Some(Err(e)),
        })
        .collect::<Result<Vec<_>, _>>()
        .map_err(|err| RdError::WalkdirError(dpath.to_path_buf(), err.to_string()))?;

    #[cfg(feature = "progressbar")]
    let pb = ProgressBar::new(entries.len() as u64);

    for entry in entries {
        tree.entry(entry.depth as u64)
            .or_insert_with(Vec::new)
            .push(entry.path());
    }

    let pool = ThreadPool::default();

    let mut handles = vec![];

    for (_, entries) in tree.into_iter().rev() {
        #[cfg(feature = "progressbar")]
        let pb = pb.clone();
        handles.push(pool.evaluate(move || {
            entries.par_iter().for_each(|entry| {
                let _ = std::fs::remove_dir_all(entry);
                #[cfg(feature = "progressbar")]
                pb.inc(1);
            });
        }));
    }

    for handle in handles {
        handle.await_complete();
    }

    if dpath.exists() {
        // Try to fix permisssion issues and delete again
        set_folder_writable(&dpath)?;

        std::fs::remove_dir_all(dpath)
            .map_err(|err| RdError::RemoveError(dpath.to_path_buf(), err))?;
    }

    #[cfg(feature = "progressbar")]
    pb.finish();

    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::fs;
    use tempfile::TempDir;

    /// Helper to create a test directory structure
    fn create_test_structure(base: &Path) -> std::io::Result<()> {
        // Create nested directories
        fs::create_dir_all(base.join("dir1/subdir1"))?;
        fs::create_dir_all(base.join("dir1/subdir2"))?;
        fs::create_dir_all(base.join("dir2"))?;

        // Create some files
        fs::write(base.join("file1.txt"), "content1")?;
        fs::write(base.join("dir1/file2.txt"), "content2")?;
        fs::write(base.join("dir1/subdir1/file3.txt"), "content3")?;
        fs::write(base.join("dir2/file4.txt"), "content4")?;

        Ok(())
    }

    /// Helper to make files read-only
    fn make_readonly(path: &Path) -> std::io::Result<()> {
        let mut perms = fs::metadata(path)?.permissions();
        perms.set_readonly(true);
        fs::set_permissions(path, perms)?;
        Ok(())
    }

    #[test]
    fn test_delete_empty_directory() {
        let temp_dir = TempDir::new().unwrap();
        let test_path = temp_dir.path().join("empty_dir");
        fs::create_dir(&test_path).unwrap();

        assert!(test_path.exists());
        delete_folder(&test_path).unwrap();
        assert!(!test_path.exists());
    }

    #[test]
    fn test_delete_directory_with_files() {
        let temp_dir = TempDir::new().unwrap();
        let test_path = temp_dir.path().join("dir_with_files");
        fs::create_dir(&test_path).unwrap();
        fs::write(test_path.join("file1.txt"), "content").unwrap();
        fs::write(test_path.join("file2.txt"), "content").unwrap();

        assert!(test_path.exists());
        delete_folder(&test_path).unwrap();
        assert!(!test_path.exists());
    }

    #[test]
    fn test_delete_nested_directory_structure() {
        let temp_dir = TempDir::new().unwrap();
        let test_path = temp_dir.path().join("nested");
        create_test_structure(&test_path).unwrap();

        assert!(test_path.exists());
        assert!(test_path.join("dir1/subdir1/file3.txt").exists());

        delete_folder(&test_path).unwrap();

        assert!(!test_path.exists());
        assert!(!test_path.join("dir1").exists());
    }

    #[test]
    fn test_delete_directory_with_readonly_files() {
        let temp_dir = TempDir::new().unwrap();
        let test_path = temp_dir.path().join("readonly_test");
        create_test_structure(&test_path).unwrap();

        // Make some files read-only
        make_readonly(&test_path.join("file1.txt")).unwrap();
        make_readonly(&test_path.join("dir1/file2.txt")).unwrap();

        assert!(test_path.exists());
        delete_folder(&test_path).unwrap();
        assert!(!test_path.exists());
    }

    #[test]
    fn test_delete_nonexistent_directory() {
        let temp_dir = TempDir::new().unwrap();
        let test_path = temp_dir.path().join("does_not_exist");

        // Should handle gracefully - directory doesn't exist
        let result = delete_folder(&test_path);

        // This might succeed (nothing to delete) or fail with WalkdirError
        // depending on jwalk's behavior
        match result {
            Ok(_) => assert!(!test_path.exists()),
            Err(RdError::WalkdirError(_, _)) => {}
            Err(e) => panic!("Unexpected error: {:?}", e),
        }
    }

    #[test]
    fn test_delete_directory_with_symlinks() {
        let temp_dir = TempDir::new().unwrap();

        // Create a directory outside the target
        let external_dir = temp_dir.path().join("external");
        fs::create_dir(&external_dir).unwrap();
        fs::write(external_dir.join("important.txt"), "don't delete me").unwrap();

        // Create target directory with symlink
        let test_path = temp_dir.path().join("with_symlink");
        fs::create_dir(&test_path).unwrap();

        #[cfg(unix)]
        {
            use std::os::unix::fs::symlink;
            symlink(&external_dir, test_path.join("link_to_external")).unwrap();
        }

        #[cfg(windows)]
        {
            use std::os::windows::fs::symlink_dir;
            symlink_dir(&external_dir, test_path.join("link_to_external")).unwrap();
        }

        // Delete target directory
        delete_folder(&test_path).unwrap();

        // Target should be gone
        assert!(!test_path.exists());

        // External directory should still exist (wasn't followed)
        assert!(external_dir.exists());
        assert!(external_dir.join("important.txt").exists());
    }

    #[test]
    fn test_set_writable_on_readonly_file() {
        let temp_dir = TempDir::new().unwrap();
        let file_path = temp_dir.path().join("readonly_file.txt");
        fs::write(&file_path, "content").unwrap();

        // Make it read-only
        make_readonly(&file_path).unwrap();
        let perms = fs::metadata(&file_path).unwrap().permissions();
        assert!(perms.readonly());

        // Make it writable using our function
        set_writable(&file_path).unwrap();

        let perms = fs::metadata(&file_path).unwrap().permissions();
        assert!(!perms.readonly());
    }

    #[test]
    fn test_delete_large_directory_structure() {
        let temp_dir = TempDir::new().unwrap();
        let test_path = temp_dir.path().join("large_structure");
        fs::create_dir(&test_path).unwrap();

        // Create many nested directories and files
        for i in 0..10 {
            let dir = test_path.join(format!("dir_{}", i));
            fs::create_dir(&dir).unwrap();

            for j in 0..5 {
                fs::write(dir.join(format!("file_{}.txt", j)), "content").unwrap();
            }

            // Create a subdirectory
            let subdir = dir.join("subdir");
            fs::create_dir(&subdir).unwrap();
            for k in 0..3 {
                fs::write(subdir.join(format!("subfile_{}.txt", k)), "content").unwrap();
            }
        }

        assert!(test_path.exists());
        delete_folder(&test_path).unwrap();
        assert!(!test_path.exists());
    }

    #[test]
    fn test_error_on_invalid_path() {
        // Test with a path that can't be walked (e.g., a file instead of directory)
        let temp_dir = TempDir::new().unwrap();
        let file_path = temp_dir.path().join("not_a_dir.txt");
        fs::write(&file_path, "content").unwrap();

        let result = delete_folder(&file_path);

        // Should succeed (remove_dir_all works on files too) or error gracefully
        // Behavior depends on the implementation
        match result {
            Ok(_) => assert!(!file_path.exists()),
            Err(_) => {} // Acceptable to error on non-directory
        }
    }
}