mime: refactor mime detection to separate module; streamline

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: I489054d2537a4c0de32d79f793478c206a6a6964

src/mime.rs

@@ -0,0 +1,149 @@
+use imagesize::ImageType;
+
+/// Detect MIME type of clipboard data. We try binary detection first using
+/// [`imagesize`] followed by a check for text/uri-list for file manager copies
+/// and finally fall back to text/plain for UTF-8 or [`None`] for binary.
+pub fn detect_mime(data: &[u8]) -> Option<String> {
+  if data.is_empty() {
+    return None;
+  }
+
+  // Try image detection first
+  if let Ok(img_type) = imagesize::image_type(data) {
+    return Some(image_type_to_mime(img_type));
+  }
+
+  // Check if it's UTF-8 text
+  if let Ok(text) = std::str::from_utf8(data) {
+    let trimmed = text.trim();
+
+    // Check for text/uri-list format (file paths from file managers)
+    if is_uri_list(trimmed) {
+      return Some("text/uri-list".to_string());
+    }
+
+    // Default to plain text
+    return Some("text/plain".to_string());
+  }
+
+  // Unknown binary data
+  None
+}
+
+/// Convert [`imagesize`] [`ImageType`] to MIME type string
+fn image_type_to_mime(img_type: ImageType) -> String {
+  let mime = match img_type {
+    ImageType::Png => "image/png",
+    ImageType::Jpeg => "image/jpeg",
+    ImageType::Gif => "image/gif",
+    ImageType::Bmp => "image/bmp",
+    ImageType::Tiff => "image/tiff",
+    ImageType::Webp => "image/webp",
+    ImageType::Aseprite => "image/x-aseprite",
+    ImageType::Dds => "image/vnd.ms-dds",
+    ImageType::Exr => "image/aces",
+    ImageType::Farbfeld => "image/farbfeld",
+    ImageType::Hdr => "image/vnd.radiance",
+    ImageType::Ico => "image/x-icon",
+    ImageType::Ilbm => "image/ilbm",
+    ImageType::Jxl => "image/jxl",
+    ImageType::Ktx2 => "image/ktx2",
+    ImageType::Pnm => "image/x-portable-anymap",
+    ImageType::Psd => "image/vnd.adobe.photoshop",
+    ImageType::Qoi => "image/qoi",
+    ImageType::Tga => "image/x-tga",
+    ImageType::Vtf => "image/x-vtf",
+    ImageType::Heif(imagesize::Compression::Hevc) => "image/heic",
+    ImageType::Heif(_) => "image/heif",
+    _ => "application/octet-stream",
+  };
+  mime.to_string()
+}
+
+/// Check if text is a URI list per RFC 2483.
+///
+/// Used when copying files from file managers - they provide file paths
+/// as text/uri-list format (`file://` URIs, one per line, `#` for comments).
+fn is_uri_list(text: &str) -> bool {
+  if text.is_empty() {
+    return false;
+  }
+
+  // Must start with a URI scheme to even consider it
+  if !text.starts_with("file://")
+    && !text.starts_with("http://")
+    && !text.starts_with("https://")
+    && !text.starts_with("ftp://")
+    && !text.starts_with('#')
+  {
+    return false;
+  }
+
+  let lines: Vec<&str> = text.lines().map(str::trim).collect();
+
+  // Check first non-comment line is a URI
+  let first_content =
+    lines.iter().find(|l| !l.is_empty() && !l.starts_with('#'));
+
+  if let Some(line) = first_content {
+    line.starts_with("file://")
+      || line.starts_with("http://")
+      || line.starts_with("https://")
+      || line.starts_with("ftp://")
+  } else {
+    false
+  }
+}
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+
+  #[test]
+  fn test_empty_data() {
+    assert_eq!(detect_mime(b""), None);
+  }
+
+  #[test]
+  fn test_plain_text() {
+    let data = b"Hello, world!";
+    assert_eq!(detect_mime(data), Some("text/plain".to_string()));
+  }
+
+  #[test]
+  fn test_uri_list_single_file() {
+    let data = b"file:///home/user/document.pdf";
+    assert_eq!(detect_mime(data), Some("text/uri-list".to_string()));
+  }
+
+  #[test]
+  fn test_uri_list_multiple_files() {
+    let data = b"file:///home/user/file1.txt\nfile:///home/user/file2.txt";
+    assert_eq!(detect_mime(data), Some("text/uri-list".to_string()));
+  }
+
+  #[test]
+  fn test_uri_list_with_comments() {
+    let data = b"# Comment\nfile:///home/user/file.txt";
+    assert_eq!(detect_mime(data), Some("text/uri-list".to_string()));
+  }
+
+  #[test]
+  fn test_uri_list_http() {
+    let data = b"https://example.com/image.png";
+    assert_eq!(detect_mime(data), Some("text/uri-list".to_string()));
+  }
+
+  #[test]
+  fn test_not_uri_list() {
+    let data = b"This is just text with file:// in the middle";
+    assert_eq!(detect_mime(data), Some("text/plain".to_string()));
+  }
+
+  #[test]
+  fn test_unknown_binary() {
+    // Binary data that's not UTF-8 and not a known format
+    let data = b"\x80\x81\x82\x83\x84\x85\x86\x87";
+    assert_eq!(detect_mime(data), None);
+  }
+}