feat(editor): paste and drop images into Markdown files (#489)

Pasting or dropping an image into a Markdown editor saves it beside the document in `assets/` and inserts a URL-encoded relative link as one undo step, in local and remote projects. Existing names get numbered suffixes; the folder and clipboard name pattern are in Settings › Editor › General. Non-Markdown editors, text paste and other dropped files keep their behavior.

Fixes #308

crates/ide-core/src/editor_settings.rs

@@ -12,6 +12,8 @@ use std::collections::BTreeMap;
 pub struct EditorGeneralSettings {
     /// Change font size with ⌘ + mouse wheel.
     pub wheel_zoom: bool,
+    pub markdown_image_folder: String,
+    pub markdown_image_name_pattern: String,
     /// Drag-and-drop of selected text inside the editor.
     pub drag_and_drop: bool,
     /// When the caret moves out of view: `minimize` scrolling | `center` the caret line.
@@ -35,6 +37,8 @@ impl Default for EditorGeneralSettings {
     fn default() -> Self {
         Self {
             wheel_zoom: false,
+            markdown_image_folder: "assets".into(),
+            markdown_image_name_pattern: "image-{timestamp}".into(),
             drag_and_drop: true,
             caret_scroll: "minimize".into(),
             soft_wrap_files: "*.md; *.txt; *.rst; *.adoc".into(),

crates/ide-host/src/ops/fs.rs

@@ -49,6 +49,10 @@ pub fn create_file(host: &Host, window: &str, path: PathBuf) -> IdeResult<()> {
     }
 }
 
+pub async fn create_file_bytes(host: &Host, path: PathBuf, data: Vec<u8>) -> IdeResult<()> {
+    host.blocking(move || ide_vfs::create_file_bytes(&path, &data)).await
+}
+
 /// Toggle Read-only Attribute: sets the writable bit (and the open document's
 /// state). Returns whether the file is read-only now.
 pub fn set_writable(host: &Host, window: &str, path: PathBuf, writable: bool) -> IdeResult<bool> {

crates/ide-host/src/rpc.rs

@@ -168,6 +168,9 @@ impl Dispatcher {
         .add("cancel_task", |c| async move { Ok(ide_core::task::cancel(c.arg::<TaskId>("id")?)) })
         .add("fs_read_dir", |c| async move { ops::fs::read_dir(&c.host, &c.window, c.arg("path")?) })
         .add("fs_create_file", |c| async move { ops::fs::create_file(&c.host, &c.window, c.arg("path")?) })
+        .add("fs_create_file_bytes", |c| async move {
+            ops::fs::create_file_bytes(&c.host, c.arg("path")?, c.arg("data")?).await
+        })
         .add("fs_create_dir", |c| async move { ide_vfs::create_dir(&c.arg::<PathBuf>("path")?) })
         .add("fs_rename", |c| async move { ide_vfs::rename(&c.arg::<PathBuf>("from")?, &c.arg::<PathBuf>("to")?) })
         .add("fs_set_writable", |c| async move {

crates/ide-vfs/src/lib.rs

@@ -232,6 +232,12 @@ pub fn save_text(path: &Path, text: &str, encoding: &str, has_bom: bool) -> IdeR
 pub fn create_file(path: &Path) -> IdeResult<()> {
     ops::create_file(path)
 }
+
+/// Creates a binary file exclusively, including missing parent directories.
+pub fn create_file_bytes(path: &Path, data: &[u8]) -> IdeResult<()> {
+    ops::create_file_bytes(path, data)
+}
+
 /// Creates a directory and missing parents; `AlreadyExists` if present.
 pub fn create_dir(path: &Path) -> IdeResult<()> {
     ops::create_dir(path)

crates/ide-vfs/src/ops.rs

@@ -35,6 +35,17 @@ pub(crate) fn create_file(path: &Path) -> IdeResult<()> {
     Ok(())
 }
 
+pub(crate) fn create_file_bytes(path: &Path, data: &[u8]) -> IdeResult<()> {
+    use std::io::Write;
+    if exists(path) {
+        return Err(already_exists(path));
+    }
+    ensure_parent(path)?;
+    let mut file = fs::OpenOptions::new().write(true).create_new(true).open(path)?;
+    file.write_all(data)?;
+    Ok(())
+}
+
 /// IDEA's "Toggle Read-only Attribute": read-only clears every write bit,
 /// writable adds the owner's.
 pub(crate) fn set_writable(path: &Path, writable: bool) -> IdeResult<()> {

crates/ide-vfs/tests/vfs.rs

@@ -367,3 +367,34 @@ fn worktree_and_nested_repository_local_excludes_are_reflected_in_listings() {
     let entries = ide_vfs::read_dir(&nested, &[]).unwrap();
     assert!(entries.iter().find(|e| e.name == "private").unwrap().ignored);
 }
+
+#[test]
+fn create_file_bytes_is_exclusive() {
+    let dir = tempfile::tempdir().unwrap();
+    let path = dir.path().join("image.png");
+    let bytes = [0, 255, 128, 10];
+    ide_vfs::create_file_bytes(&path, &bytes).unwrap();
+    let error = ide_vfs::create_file_bytes(&path, b"replacement").unwrap_err();
+    assert_eq!(error.kind, ide_core::error::ErrorKind::AlreadyExists);
+    assert_eq!(std::fs::read(&path).unwrap(), bytes);
+}
+
+#[test]
+fn create_file_bytes_creates_parents() {
+    let dir = tempfile::tempdir().unwrap();
+    let path = dir.path().join("nested/assets/image.png");
+    ide_vfs::create_file_bytes(&path, &[0, 255]).unwrap();
+    assert_eq!(std::fs::read(path).unwrap(), [0, 255]);
+}
+
+#[cfg(unix)]
+#[test]
+fn create_file_bytes_does_not_follow_existing_symlink() {
+    let dir = tempfile::tempdir().unwrap();
+    let target = dir.path().join("target.png");
+    let link = dir.path().join("link.png");
+    std::os::unix::fs::symlink(&target, &link).unwrap();
+    let error = ide_vfs::create_file_bytes(&link, b"data").unwrap_err();
+    assert_eq!(error.kind, ide_core::error::ErrorKind::AlreadyExists);
+    assert!(!target.exists());
+}