refactor: drop change.rs <3 (#447)

![patrick-zen
png](https://github.com/user-attachments/assets/bc491335-4f23-47d0-ace6-2c408eb1e93e)

as per PR title. notable changes:
- drop `change.rs` in favour of a simple `update_document` api that
replaces the content
- simplify `StatementId` to just be a simple wrapper around the actual
statement string. The content is wrapped in an `Arc<str>` to make
cloning cheap. turns out string interning only makes sense when we have
a lot of duplicate strings. `Arc<str>` is much more efficient and
simpler in our case.
- Remove `document.rs` and merge it into `parsed_document` to then
rename it to `Document`
- replaces the `strum` usage to get the available command because it
didn't feel right to make an empty string the default for a StatementId.
replaced it with a simple manual implementation.

I ran a few benchmarks and the statement splitter performance seems to
be good enough to run it on every keystroke on the entire file.
```sh
large statement with length 863000                                                                            
                        time:   [23.180 ms 23.278 ms 23.386 ms]

small statement with length 19000                                                                            
                        time:   [886.69 µs 890.91 µs 896.35 µs]
```

ToDo
- [ ] add some tests
- [x] cleanup

Author: psteinroe

.claude/settings.local.json

@@ -6,7 +6,8 @@
       "Bash(cargo test:*)",
       "Bash(cargo run:*)",
       "Bash(cargo check:*)",
-      "Bash(cargo fmt:*)"
+      "Bash(cargo fmt:*)",
+      "Bash(cargo doc:*)"
     ],
     "deny": []
   }

Cargo.lock

@@ -2,13 +2,14 @@ use crate::execute::diagnostics::{ResultExt, ResultIoExt};
 use crate::execute::process_file::SharedTraversalOptions;
 use pgt_diagnostics::{Error, category};
 use pgt_fs::{File, OpenOptions, PgTPath};
-use pgt_workspace::workspace::{ChangeParams, FileGuard, OpenFileParams};
+use pgt_workspace::workspace::{FileGuard, OpenFileParams};
 use pgt_workspace::{Workspace, WorkspaceError};
 use std::path::{Path, PathBuf};
 
 /// Small wrapper that holds information and operations around the current processed file
 pub(crate) struct WorkspaceFile<'ctx, 'app> {
     guard: FileGuard<'app, dyn Workspace + 'ctx>,
+    #[allow(dead_code)]
     file: Box<dyn File>,
     pub(crate) path: PathBuf,
 }
@@ -57,19 +58,4 @@ impl<'ctx, 'app> WorkspaceFile<'ctx, 'app> {
     pub(crate) fn input(&self) -> Result<String, WorkspaceError> {
         self.guard().get_file_content()
     }
-
-    /// It updates the workspace file with `new_content`
-    #[allow(dead_code)]
-    pub(crate) fn update_file(&mut self, new_content: impl Into<String>) -> Result<(), Error> {
-        let new_content = new_content.into();
-
-        self.file
-            .set_content(new_content.as_bytes())
-            .with_file_path(self.path.display().to_string())?;
-        self.guard.change_file(
-            self.file.file_version(),
-            vec![ChangeParams::overwrite(new_content)],
-        )?;
-        Ok(())
-    }
 }

crates/pgt_cli/src/execute/process_file/workspace_file.rs

@@ -1,4 +1,5 @@
 use crate::adapters::{PositionEncoding, WideEncoding, negotiated_encoding};
+use crate::handlers::code_actions::command_id;
 use pgt_workspace::features::code_actions::CommandActionCategory;
 use strum::IntoEnumIterator;
 use tower_lsp::lsp_types::{
@@ -7,8 +8,6 @@ use tower_lsp::lsp_types::{
     TextDocumentSyncOptions, TextDocumentSyncSaveOptions, WorkDoneProgressOptions,
 };
 
-use crate::handlers::code_actions::command_id;
-
 /// The capabilities to send from server as part of [`InitializeResult`]
 ///
 /// [`InitializeResult`]: lspower::lsp::InitializeResult
@@ -54,7 +53,6 @@ pub(crate) fn server_capabilities(capabilities: &ClientCapabilities) -> ServerCa
             commands: CommandActionCategory::iter()
                 .map(|c| command_id(&c))
                 .collect::<Vec<String>>(),
-
             ..Default::default()
         }),
         document_formatting_provider: None,

crates/pgt_lsp/src/capabilities.rs

@@ -1,10 +1,9 @@
-use crate::adapters::from_lsp;
 use crate::{
     diagnostics::LspError, documents::Document, session::Session, utils::apply_document_changes,
 };
 use anyhow::Result;
 use pgt_workspace::workspace::{
-    ChangeFileParams, ChangeParams, CloseFileParams, GetFileContentParams, OpenFileParams,
+    ChangeFileParams, CloseFileParams, GetFileContentParams, OpenFileParams,
 };
 use tower_lsp::lsp_types;
 use tracing::error;
@@ -48,40 +47,28 @@ pub(crate) async fn did_change(
 
     let pgt_path = session.file_path(&url)?;
 
-    let old_doc = session.document(&url)?;
     let old_text = session.workspace.get_file_content(GetFileContentParams {
         path: pgt_path.clone(),
     })?;
-
-    let start = params
-        .content_changes
-        .iter()
-        .rev()
-        .position(|change| change.range.is_none())
-        .map_or(0, |idx| params.content_changes.len() - idx - 1);
+    tracing::trace!("old document: {:?}", old_text);
+    tracing::trace!("content changes: {:?}", params.content_changes);
 
     let text = apply_document_changes(
         session.position_encoding(),
         old_text,
-        &params.content_changes[start..],
+        &params.content_changes,
     );
 
+    tracing::trace!("new document: {:?}", text);
+
+    session.insert_document(url.clone(), Document::new(version, &text));
+
     session.workspace.change_file(ChangeFileParams {
         path: pgt_path,
         version,
-        changes: params.content_changes[start..]
-            .iter()
-            .map(|c| ChangeParams {
-                range: c.range.and_then(|r| {
-                    from_lsp::text_range(&old_doc.line_index, r, session.position_encoding()).ok()
-                }),
-                text: c.text.clone(),
-            })
-            .collect(),
+        content: text,
     })?;
 
-    session.insert_document(url.clone(), Document::new(version, &text));
-
     if let Err(err) = session.update_diagnostics(url).await {
         error!("Failed to update diagnostics: {}", err);
     }

crates/pgt_lsp/src/handlers/text_document.rs

@@ -19,4 +19,9 @@ pgt_text_size.workspace = true
 regex.workspace         = true
 
 [dev-dependencies]
-ntest = "0.9.3"
+criterion = "0.3"
+ntest     = "0.9.3"
+
+[[bench]]
+harness = false
+name    = "splitter"