file-dialogs.md

File Dialogs and Operations

Overview

The file operations module provides native file dialog integration and file I/O utilities for opening, reading, and writing files. It uses the rfd crate for cross-platform native file dialogs.

The application integrates these dialogs into the File menu and supports keyboard shortcuts for common operations.

Key Files

• src/files/mod.rs - Module declaration and re-exports
• src/files/dialogs.rs - Native file dialog functions using rfd
• src/files/operations.rs - File I/O utilities with error handling

Implementation Details

File Dialog Functions

The dialogs.rs module provides three main dialog functions:

// Open single file (legacy, less commonly used)
pub fn open_file_dialog(initial_dir: Option<&PathBuf>) -> Option<PathBuf>

// Open multiple files (primary open method - supports Ctrl/Shift selection)
pub fn open_multiple_files_dialog(initial_dir: Option<&PathBuf>) -> Vec<PathBuf>

// Save file dialog
pub fn save_file_dialog(initial_dir: Option<&PathBuf>, default_name: Option<&str>) -> Option<PathBuf>

Note: The app primarily uses open_multiple_files_dialog for File > Open, allowing users to select multiple files at once.

All dialogs include filters for:

• Markdown Files (.md, .markdown, .mdown, .mkd, .mkdn)
• Text Files (.txt, .text)
• All Files (*)

FileDialogOptions Builder

For more control, use the FileDialogOptions builder:

let path = FileDialogOptions::new()
    .title("Open Markdown File")
    .initial_dir(PathBuf::from("/home/user/docs"))
    .open_file();

File Operations

The operations.rs module provides utilities:

Function	Purpose
read_file_contents()	Read file with error handling
write_file_contents()	Write file, creating parent dirs
validate_file_path()	Check path exists and is readable
get_file_size()	Get file size in bytes
is_likely_text_file()	Heuristic check for text vs binary
ensure_parent_dir()	Create parent directories if needed

Error Handling

File operations return Result<T> with these error types:

• Error::FileNotFound - File doesn't exist
• Error::PermissionDenied - Access denied
• Error::FileRead - Read failure with source error
• Error::FileWrite - Write failure with source error

Dependencies Used

• rfd = "0.14" - Rusty File Dialogs for native OS dialogs
• log - Logging for debug/info/warn messages

Menu Integration

The File menu in app.rs provides these operations:

Menu Item	Shortcut	Handler	Description
New	Ctrl+N	state.new_tab()	Creates a new empty tab
Open...	Ctrl+O	handle_open_file()	Opens native file dialog
Save	Ctrl+S	handle_save_file()	Saves to existing path (or triggers Save As)
Save As...	Ctrl+Shift+S	handle_save_as_file()	Opens native save dialog
Exit	-	request_exit()	Exits with unsaved changes check

Keyboard Shortcuts

Shortcuts are handled in handle_keyboard_shortcuts() using egui's input system:

enum KeyboardAction {
    Save,      // Ctrl+S
    SaveAs,    // Ctrl+Shift+S
    Open,      // Ctrl+O
    New,       // Ctrl+N
}

The handler detects key presses in an input closure and returns an action enum to avoid borrow conflicts, then executes the action outside the closure.

Usage

Opening Files (Multiple Selection)

use crate::files::dialogs::open_multiple_files_dialog;

// In app.rs handle_open_file()
let paths = open_multiple_files_dialog(initial_dir.as_ref());

for path in paths {
    match self.state.open_file(path) {
        Ok(_) => success_count += 1,
        Err(e) => warn!("Failed to open: {}", e),
    }
}

// Show toast for multiple files
if file_count > 1 && success_count > 0 {
    self.state.show_toast(format!("Opened {} files", success_count), time, 2.0);
}

Reading File Contents

use crate::files::operations::read_file_contents;

match read_file_contents(&path) {
    Ok(content) => println!("Content: {}", content),
    Err(Error::FileNotFound(_)) => println!("File not found"),
    Err(e) => println!("Error: {}", e),
}

Saving a File

// Save to existing path (handle_save_file)
fn handle_save_file(&mut self) {
    let has_path = self.state.active_tab()
        .map(|t| t.path.is_some())
        .unwrap_or(false);

    if has_path {
        match self.state.save_active_tab() {
            Ok(_) => debug!("File saved"),
            Err(e) => self.state.set_status(format!("Error: {}", e)),
        }
    } else {
        self.handle_save_as_file(); // No path, trigger Save As
    }
}

Save As

use crate::files::dialogs::save_file_dialog;

// Get initial directory and default filename
let initial_dir = /* from current file or recent files */;
let default_name = /* from tab path or "untitled.md" */;

if let Some(path) = save_file_dialog(initial_dir.as_ref(), Some(&default_name)) {
    match self.state.save_active_tab_as(path.clone()) {
        Ok(_) => self.state.set_status(format!("Saved: {}", path.display())),
        Err(e) => self.state.set_status(format!("Error: {}", e)),
    }
}

Writing File Contents (Low-level)

use crate::files::operations::write_file_contents;

write_file_contents(&path, "# Hello World")?;
// Parent directories are created automatically

Dirty State Tracking

The Tab struct tracks unsaved changes:

impl Tab {
    /// Check if content differs from saved version
    pub fn is_modified(&self) -> bool {
        self.content != self.original_content
    }

    /// Mark current content as saved
    pub fn mark_saved(&mut self) {
        self.original_content = self.content.clone();
    }

    /// Title shows asterisk for modified tabs
    pub fn title(&self) -> String {
        let name = /* filename or "Untitled" */;
        if self.is_modified() {
            format!("{}*", name)
        } else {
            name.to_string()
        }
    }
}

Tests

Run file operation tests:

cargo test files::

Test coverage includes:

• Reading existing files
• Reading non-existent files (FileNotFound error)
• Writing files (creates parent directories)
• Path validation
• File size retrieval
• Text vs binary file detection
• FileDialogOptions builder pattern