rawlib 0.3.1

High-performance RAW image thumbnail extractor with batch processing support
Documentation 
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//! Utility functions

use crate::error::{Error, Result};
use log::debug;
use std::path::{Path, PathBuf};

/// 查找可用的文件名（通过添加数字后缀）
/// 
/// 例如: file.jpg -> file_1.jpg -> file_2.jpg ...
pub fn find_available_filename(base: &Path) -> Result<PathBuf> {
    if !base.exists() {
        return Ok(base.to_path_buf());
    }
    
    let parent = base.parent().unwrap_or_else(|| Path::new("."));
    let stem = base.file_stem()
        .and_then(|s| s.to_str())
        .ok_or_else(|| Error::Config { 
            message: format!("Invalid file name: {}", base.display()) 
        })?;
    let extension = base.extension()
        .and_then(|e| e.to_str())
        .unwrap_or("");
    
    for i in 1..10000 {
        let new_name = if extension.is_empty() {
            format!("{}_{}", stem, i)
        } else {
            format!("{}_{}.{}", stem, i, extension)
        };
        
        let new_path = parent.join(&new_name);
        if !new_path.exists() {
            debug!("Found available filename: {}", new_path.display());
            return Ok(new_path);
        }
    }
    
    Err(Error::CannotCreateOutput { 
        path: base.to_path_buf(), 
        attempts: 10000 
    })
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::fs;
    use tempfile::TempDir;
    
    #[test]
    fn test_find_available_filename() {
        let temp_dir = TempDir::new().unwrap();
        let base = temp_dir.path().join("test.jpg");
        
        // 文件不存在时返回原文件名
        let result = find_available_filename(&base).unwrap();
        assert_eq!(result, base);
        
        // 创建文件后，应该返回 test_1.jpg
        fs::write(&base, b"test").unwrap();
        let result = find_available_filename(&base).unwrap();
        assert_eq!(result, temp_dir.path().join("test_1.jpg"));
        
        // 创建 test_1.jpg 后，应该返回 test_2.jpg
        fs::write(&result, b"test").unwrap();
        let result = find_available_filename(&base).unwrap();
        assert_eq!(result, temp_dir.path().join("test_2.jpg"));
    }
    
    #[test]
    fn test_find_available_filename_no_extension() {
        let temp_dir = TempDir::new().unwrap();
        let base = temp_dir.path().join("test");
        
        fs::write(&base, b"test").unwrap();
        let result = find_available_filename(&base).unwrap();
        assert_eq!(result, temp_dir.path().join("test_1"));
    }
}