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import * as vscode from 'vscode';
import { Ctx, Disposable } from './ctx';
import { RustEditor, isRustEditor } from './util';
// FIXME: consider implementing this via the Tree View API?
// https://code.visualstudio.com/api/extension-guides/tree-view
export class AstInspector implements vscode.HoverProvider, vscode.DefinitionProvider, Disposable {
private readonly astDecorationType = vscode.window.createTextEditorDecorationType({
borderColor: new vscode.ThemeColor('rust_analyzer.syntaxTreeBorder'),
borderStyle: "solid",
borderWidth: "2px",
});
private rustEditor: undefined | RustEditor;
// Lazy rust token range -> syntax tree file range.
private readonly rust2Ast = new Lazy(() => {
const astEditor = this.findAstTextEditor();
if (!this.rustEditor || !astEditor) return undefined;
const buf: [vscode.Range, vscode.Range][] = [];
for (let i = 0; i < astEditor.document.lineCount; ++i) {
const astLine = astEditor.document.lineAt(i);
// Heuristically look for nodes with quoted text (which are token nodes)
const isTokenNode = astLine.text.lastIndexOf('"') >= 0;
if (!isTokenNode) continue;
const rustRange = this.parseRustTextRange(this.rustEditor.document, astLine.text);
if (!rustRange) continue;
buf.push([rustRange, this.findAstNodeRange(astLine)]);
}
return buf;
});
constructor(ctx: Ctx) {
ctx.pushCleanup(vscode.languages.registerHoverProvider({ scheme: 'rust-analyzer' }, this));
ctx.pushCleanup(vscode.languages.registerDefinitionProvider({ language: "rust" }, this));
vscode.workspace.onDidCloseTextDocument(this.onDidCloseTextDocument, this, ctx.subscriptions);
vscode.workspace.onDidChangeTextDocument(this.onDidChangeTextDocument, this, ctx.subscriptions);
vscode.window.onDidChangeVisibleTextEditors(this.onDidChangeVisibleTextEditors, this, ctx.subscriptions);
ctx.pushCleanup(this);
}
dispose() {
this.setRustEditor(undefined);
}
private onDidChangeTextDocument(event: vscode.TextDocumentChangeEvent) {
if (this.rustEditor && event.document.uri.toString() === this.rustEditor.document.uri.toString()) {
this.rust2Ast.reset();
}
}
private onDidCloseTextDocument(doc: vscode.TextDocument) {
if (this.rustEditor && doc.uri.toString() === this.rustEditor.document.uri.toString()) {
this.setRustEditor(undefined);
}
}
private onDidChangeVisibleTextEditors(editors: vscode.TextEditor[]) {
if (!this.findAstTextEditor()) {
this.setRustEditor(undefined);
return;
}
this.setRustEditor(editors.find(isRustEditor));
}
private findAstTextEditor(): undefined | vscode.TextEditor {
return vscode.window.visibleTextEditors.find(it => it.document.uri.scheme === 'rust-analyzer');
}
private setRustEditor(newRustEditor: undefined | RustEditor) {
if (this.rustEditor && this.rustEditor !== newRustEditor) {
this.rustEditor.setDecorations(this.astDecorationType, []);
this.rust2Ast.reset();
}
this.rustEditor = newRustEditor;
}
// additional positional params are omitted
provideDefinition(doc: vscode.TextDocument, pos: vscode.Position): vscode.ProviderResult<vscode.DefinitionLink[]> {
if (!this.rustEditor || doc.uri.toString() !== this.rustEditor.document.uri.toString()) return;
const astEditor = this.findAstTextEditor();
if (!astEditor) return;
const rust2AstRanges = this.rust2Ast.get()?.find(([rustRange, _]) => rustRange.contains(pos));
if (!rust2AstRanges) return;
const [rustFileRange, astFileRange] = rust2AstRanges;
astEditor.revealRange(astFileRange);
astEditor.selection = new vscode.Selection(astFileRange.start, astFileRange.end);
return [{
targetRange: astFileRange,
targetUri: astEditor.document.uri,
originSelectionRange: rustFileRange,
targetSelectionRange: astFileRange,
}];
}
// additional positional params are omitted
provideHover(doc: vscode.TextDocument, hoverPosition: vscode.Position): vscode.ProviderResult<vscode.Hover> {
if (!this.rustEditor) return;
const astFileLine = doc.lineAt(hoverPosition.line);
const rustFileRange = this.parseRustTextRange(this.rustEditor.document, astFileLine.text);
if (!rustFileRange) return;
this.rustEditor.setDecorations(this.astDecorationType, [rustFileRange]);
this.rustEditor.revealRange(rustFileRange);
const rustSourceCode = this.rustEditor.document.getText(rustFileRange);
const astFileRange = this.findAstNodeRange(astFileLine);
return new vscode.Hover(["```rust\n" + rustSourceCode + "\n```"], astFileRange);
}
private findAstNodeRange(astLine: vscode.TextLine): vscode.Range {
const lineOffset = astLine.range.start;
const begin = lineOffset.translate(undefined, astLine.firstNonWhitespaceCharacterIndex);
const end = lineOffset.translate(undefined, astLine.text.trimEnd().length);
return new vscode.Range(begin, end);
}
private parseRustTextRange(doc: vscode.TextDocument, astLine: string): undefined | vscode.Range {
const parsedRange = /(\d+)\.\.(\d+)/.exec(astLine);
if (!parsedRange) return;
const [begin, end] = parsedRange
.slice(1)
.map(off => this.positionAt(doc, +off));
return new vscode.Range(begin, end);
}
// Memoize the last value, otherwise the CPU is at 100% single core
// with quadratic lookups when we build rust2Ast cache
cache?: { doc: vscode.TextDocument; offset: number; line: number };
positionAt(doc: vscode.TextDocument, targetOffset: number): vscode.Position {
if (doc.eol === vscode.EndOfLine.LF) {
return doc.positionAt(targetOffset);
}
// Dirty workaround for crlf line endings
// We are still in this prehistoric era of carriage returns here...
let line = 0;
let offset = 0;
const cache = this.cache;
if (cache?.doc === doc && cache.offset <= targetOffset) {
({ line, offset } = cache);
}
while (true) {
const lineLenWithLf = doc.lineAt(line).text.length + 1;
if (offset + lineLenWithLf > targetOffset) {
this.cache = { doc, offset, line };
return doc.positionAt(targetOffset + line);
}
offset += lineLenWithLf;
line += 1;
}
}
}
class Lazy<T> {
val: undefined | T;
constructor(private readonly compute: () => undefined | T) { }
get() {
return this.val ?? (this.val = this.compute());
}
reset() {
this.val = undefined;
}
}
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