make path changes LSP spec conform (#8949)

Currently, helix implements operations which change the paths of files
incorrectly and inconsistently. This PR ensures that we do the following
whenever a buffer is renamed (`:move` and workspace edits)

* always send did_open/did_close notifications
* send will_rename/did_rename requests correctly
  * send them to all LSP servers not just those that are active for a
    buffer
  * also send these requests for paths that are not yet open in a buffer (if
    triggered from workspace edit).
  * only send these if the server registered interests in the path
* autodetect language, indent, line ending, ..

This PR also centralizes the infrastructure for path setting and
therefore `:w <path>` benefits from similar fixed (but without didRename)

1 files changed, 229 insertions, 0 deletions

diff --git a/helix-view/src/handlers/lsp.rs b/helix-view/src/handlers/lsp.rs
index 1dae45dd..beb106b2 100644
--- a/helix-view/src/handlers/lsp.rs
+++ b/helix-view/src/handlers/lsp.rs
@@ -1,4 +1,8 @@
+use crate::editor::Action;
+use crate::Editor;
 use crate::{DocumentId, ViewId};
+use helix_lsp::util::generate_transaction_from_edits;
+use helix_lsp::{lsp, OffsetEncoding};
 
 pub enum CompletionEvent {
     /// Auto completion was triggered by typing a word char
@@ -39,3 +43,228 @@ pub enum SignatureHelpEvent {
     Cancel,
     RequestComplete { open: bool },
 }
+
+#[derive(Debug)]
+pub struct ApplyEditError {
+    pub kind: ApplyEditErrorKind,
+    pub failed_change_idx: usize,
+}
+
+#[derive(Debug)]
+pub enum ApplyEditErrorKind {
+    DocumentChanged,
+    FileNotFound,
+    UnknownURISchema,
+    IoError(std::io::Error),
+    // TODO: check edits before applying and propagate failure
+    // InvalidEdit,
+}
+
+impl ToString for ApplyEditErrorKind {
+    fn to_string(&self) -> String {
+        match self {
+            ApplyEditErrorKind::DocumentChanged => "document has changed".to_string(),
+            ApplyEditErrorKind::FileNotFound => "file not found".to_string(),
+            ApplyEditErrorKind::UnknownURISchema => "URI schema not supported".to_string(),
+            ApplyEditErrorKind::IoError(err) => err.to_string(),
+        }
+    }
+}
+
+impl Editor {
+    fn apply_text_edits(
+        &mut self,
+        uri: &helix_lsp::Url,
+        version: Option<i32>,
+        text_edits: Vec<lsp::TextEdit>,
+        offset_encoding: OffsetEncoding,
+    ) -> Result<(), ApplyEditErrorKind> {
+        let path = match uri.to_file_path() {
+            Ok(path) => path,
+            Err(_) => {
+                let err = format!("unable to convert URI to filepath: {}", uri);
+                log::error!("{}", err);
+                self.set_error(err);
+                return Err(ApplyEditErrorKind::UnknownURISchema);
+            }
+        };
+
+        let doc_id = match self.open(&path, Action::Load) {
+            Ok(doc_id) => doc_id,
+            Err(err) => {
+                let err = format!("failed to open document: {}: {}", uri, err);
+                log::error!("{}", err);
+                self.set_error(err);
+                return Err(ApplyEditErrorKind::FileNotFound);
+            }
+        };
+
+        let doc = doc_mut!(self, &doc_id);
+        if let Some(version) = version {
+            if version != doc.version() {
+                let err = format!("outdated workspace edit for {path:?}");
+                log::error!("{err}, expected {} but got {version}", doc.version());
+                self.set_error(err);
+                return Err(ApplyEditErrorKind::DocumentChanged);
+            }
+        }
+
+        // Need to determine a view for apply/append_changes_to_history
+        let view_id = self.get_synced_view_id(doc_id);
+        let doc = doc_mut!(self, &doc_id);
+
+        let transaction = generate_transaction_from_edits(doc.text(), text_edits, offset_encoding);
+        let view = view_mut!(self, view_id);
+        doc.apply(&transaction, view.id);
+        doc.append_changes_to_history(view);
+        Ok(())
+    }
+
+    // TODO make this transactional (and set failureMode to transactional)
+    pub fn apply_workspace_edit(
+        &mut self,
+        offset_encoding: OffsetEncoding,
+        workspace_edit: &lsp::WorkspaceEdit,
+    ) -> Result<(), ApplyEditError> {
+        if let Some(ref document_changes) = workspace_edit.document_changes {
+            match document_changes {
+                lsp::DocumentChanges::Edits(document_edits) => {
+                    for (i, document_edit) in document_edits.iter().enumerate() {
+                        let edits = document_edit
+                            .edits
+                            .iter()
+                            .map(|edit| match edit {
+                                lsp::OneOf::Left(text_edit) => text_edit,
+                                lsp::OneOf::Right(annotated_text_edit) => {
+                                    &annotated_text_edit.text_edit
+                                }
+                            })
+                            .cloned()
+                            .collect();
+                        self.apply_text_edits(
+                            &document_edit.text_document.uri,
+                            document_edit.text_document.version,
+                            edits,
+                            offset_encoding,
+                        )
+                        .map_err(|kind| ApplyEditError {
+                            kind,
+                            failed_change_idx: i,
+                        })?;
+                    }
+                }
+                lsp::DocumentChanges::Operations(operations) => {
+                    log::debug!("document changes - operations: {:?}", operations);
+                    for (i, operation) in operations.iter().enumerate() {
+                        match operation {
+                            lsp::DocumentChangeOperation::Op(op) => {
+                                self.apply_document_resource_op(op).map_err(|io| {
+                                    ApplyEditError {
+                                        kind: ApplyEditErrorKind::IoError(io),
+                                        failed_change_idx: i,
+                                    }
+                                })?;
+                            }
+
+                            lsp::DocumentChangeOperation::Edit(document_edit) => {
+                                let edits = document_edit
+                                    .edits
+                                    .iter()
+                                    .map(|edit| match edit {
+                                        lsp::OneOf::Left(text_edit) => text_edit,
+                                        lsp::OneOf::Right(annotated_text_edit) => {
+                                            &annotated_text_edit.text_edit
+                                        }
+                                    })
+                                    .cloned()
+                                    .collect();
+                                self.apply_text_edits(
+                                    &document_edit.text_document.uri,
+                                    document_edit.text_document.version,
+                                    edits,
+                                    offset_encoding,
+                                )
+                                .map_err(|kind| {
+                                    ApplyEditError {
+                                        kind,
+                                        failed_change_idx: i,
+                                    }
+                                })?;
+                            }
+                        }
+                    }
+                }
+            }
+
+            return Ok(());
+        }
+
+        if let Some(ref changes) = workspace_edit.changes {
+            log::debug!("workspace changes: {:?}", changes);
+            for (i, (uri, text_edits)) in changes.iter().enumerate() {
+                let text_edits = text_edits.to_vec();
+                self.apply_text_edits(uri, None, text_edits, offset_encoding)
+                    .map_err(|kind| ApplyEditError {
+                        kind,
+                        failed_change_idx: i,
+                    })?;
+            }
+        }
+
+        Ok(())
+    }
+
+    fn apply_document_resource_op(&mut self, op: &lsp::ResourceOp) -> std::io::Result<()> {
+        use lsp::ResourceOp;
+        use std::fs;
+        match op {
+            ResourceOp::Create(op) => {
+                let path = op.uri.to_file_path().unwrap();
+                let ignore_if_exists = op.options.as_ref().map_or(false, |options| {
+                    !options.overwrite.unwrap_or(false) && options.ignore_if_exists.unwrap_or(false)
+                });
+                if !ignore_if_exists || !path.exists() {
+                    // Create directory if it does not exist
+                    if let Some(dir) = path.parent() {
+                        if !dir.is_dir() {
+                            fs::create_dir_all(dir)?;
+                        }
+                    }
+
+                    fs::write(&path, [])?;
+                    self.language_servers.file_event_handler.file_changed(path);
+                }
+            }
+            ResourceOp::Delete(op) => {
+                let path = op.uri.to_file_path().unwrap();
+                if path.is_dir() {
+                    let recursive = op
+                        .options
+                        .as_ref()
+                        .and_then(|options| options.recursive)
+                        .unwrap_or(false);
+
+                    if recursive {
+                        fs::remove_dir_all(&path)?
+                    } else {
+                        fs::remove_dir(&path)?
+                    }
+                    self.language_servers.file_event_handler.file_changed(path);
+                } else if path.is_file() {
+                    fs::remove_file(&path)?;
+                }
+            }
+            ResourceOp::Rename(op) => {
+                let from = op.old_uri.to_file_path().unwrap();
+                let to = op.new_uri.to_file_path().unwrap();
+                let ignore_if_exists = op.options.as_ref().map_or(false, |options| {
+                    !options.overwrite.unwrap_or(false) && options.ignore_if_exists.unwrap_or(false)
+                });
+                if !ignore_if_exists || !to.exists() {
+                    self.move_path(&from, &to)?;
+                }
+            }
+        }
+        Ok(())
+    }
+}