fix: bridge remote clipboard image paste

refs #205

1 files changed, 128 insertions, 0 deletions

diff --git a/src/server/clipboard_image.rs b/src/server/clipboard_image.rs
new file mode 100644
index 00000000..299267d3
--- /dev/null
+++ b/src/server/clipboard_image.rs
@@ -0,0 +1,128 @@
+use std::fs;
+use std::io::{self, Write as _};
+use std::path::{Path, PathBuf};
+use std::time::{Duration, SystemTime, UNIX_EPOCH};
+
+const STAGED_CLIPBOARD_IMAGE_MAX_AGE: Duration = Duration::from_secs(24 * 60 * 60);
+
+pub(crate) struct StagedClipboardImage {
+    pub(crate) path: PathBuf,
+    pub(crate) paste_text: String,
+}
+
+pub(crate) fn stage(
+    client_id: u64,
+    extension: &str,
+    data: &[u8],
+) -> io::Result<StagedClipboardImage> {
+    use std::os::unix::fs::OpenOptionsExt;
+
+    let extension = sanitize_extension(extension);
+    let dir = ensure_staging_dir()?;
+    cleanup_stale(&dir);
+
+    let unique = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .map(|duration| duration.as_nanos())
+        .unwrap_or(0);
+
+    for attempt in 0..100 {
+        let path = dir.join(format!(
+            "client-{client_id}-clipboard-{unique}-{attempt}.{extension}"
+        ));
+        let mut file = match fs::OpenOptions::new()
+            .write(true)
+            .create_new(true)
+            .mode(0o600)
+            .open(&path)
+        {
+            Ok(file) => file,
+            Err(err) if err.kind() == io::ErrorKind::AlreadyExists => continue,
+            Err(err) => return Err(err),
+        };
+        file.write_all(data)?;
+        return Ok(StagedClipboardImage {
+            paste_text: path.to_string_lossy().into_owned(),
+            path,
+        });
+    }
+
+    Err(io::Error::new(
+        io::ErrorKind::AlreadyExists,
+        "failed to allocate unique clipboard image staging path",
+    ))
+}
+
+pub(crate) fn remove_files(paths: Vec<PathBuf>) {
+    for path in paths {
+        let _ = fs::remove_file(path);
+    }
+}
+
+fn sanitize_extension(extension: &str) -> &'static str {
+    if extension.eq_ignore_ascii_case("png") {
+        "png"
+    } else if extension.eq_ignore_ascii_case("jpg") || extension.eq_ignore_ascii_case("jpeg") {
+        "jpg"
+    } else if extension.eq_ignore_ascii_case("gif") {
+        "gif"
+    } else if extension.eq_ignore_ascii_case("webp") {
+        "webp"
+    } else if extension.eq_ignore_ascii_case("bmp") {
+        "bmp"
+    } else {
+        "png"
+    }
+}
+
+fn staging_dir() -> PathBuf {
+    let user_id = unsafe { libc::geteuid() };
+    std::env::temp_dir().join(format!("herdr-clipboard-images-{user_id}"))
+}
+
+fn ensure_staging_dir() -> io::Result<PathBuf> {
+    use std::os::unix::fs::PermissionsExt;
+
+    let dir = staging_dir();
+    fs::create_dir_all(&dir)?;
+    let metadata = fs::metadata(&dir)?;
+    if !metadata.is_dir() {
+        return Err(io::Error::other(format!(
+            "clipboard image staging path is not a directory: {}",
+            dir.display()
+        )));
+    }
+    fs::set_permissions(&dir, fs::Permissions::from_mode(0o700))?;
+    Ok(dir)
+}
+
+fn cleanup_stale(dir: &Path) {
+    let Ok(entries) = fs::read_dir(dir) else {
+        return;
+    };
+    for entry in entries.flatten() {
+        let path = entry.path();
+        let Ok(metadata) = entry.metadata() else {
+            continue;
+        };
+        let Ok(modified) = metadata.modified() else {
+            continue;
+        };
+        if modified.elapsed().unwrap_or_default() > STAGED_CLIPBOARD_IMAGE_MAX_AGE {
+            let _ = fs::remove_file(path);
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn sanitize_extension_accepts_known_image_extensions() {
+        assert_eq!(sanitize_extension("PNG"), "png");
+        assert_eq!(sanitize_extension("jpeg"), "jpg");
+        assert_eq!(sanitize_extension("webp"), "webp");
+        assert_eq!(sanitize_extension("sh"), "png");
+    }
+}