From 5b87490ba50cfb5faf49ba62cc2fb7db94487be3 Mon Sep 17 00:00:00 2001
From: Mattias Wadman <mattias.wadman@gmail.com>
Date: Wed, 5 Jul 2017 22:26:56 +0200
Subject: [PATCH] Format via stdin instead of document file path

Fixes double save issues as now we don't have to save
the document to do formatting.

Also fixes save on "Format Document" (now no save is done).

Related to #1037
---
 src/goFormat.ts | 10 +++++-----
 src/goMain.ts   | 41 +++++++++++++++--------------------------
 2 files changed, 20 insertions(+), 31 deletions(-)

diff --git a/src/goFormat.ts b/src/goFormat.ts
index 8f9d69759..c5552a07a 100644
--- a/src/goFormat.ts
+++ b/src/goFormat.ts
@@ -16,6 +16,7 @@ export class Formatter {
 	public formatDocument(document: vscode.TextDocument): Thenable<vscode.TextEdit[]> {
 		return new Promise((resolve, reject) => {
 			let filename = document.fileName;
+			let documentText = document.getText();
 			let formatTool = vscode.workspace.getConfiguration('go')['formatTool'] || 'goreturns';
 			let formatCommandBinPath = getBinPath(formatTool);
 			let formatFlags = vscode.workspace.getConfiguration('go')['formatFlags'] || [];
@@ -29,7 +30,7 @@ export class Formatter {
 			}
 			let t0 = Date.now();
 			let env = getToolsEnvVars();
-			cp.execFile(formatCommandBinPath, [...formatFlags, filename], {env}, (err, stdout, stderr) => {
+			let process = cp.execFile(formatCommandBinPath, [...formatFlags], {env}, (err, stdout, stderr) => {
 				try {
 					if (err && (<any>err).code === 'ENOENT') {
 						promptForMissingTool(formatTool);
@@ -41,7 +42,7 @@ export class Formatter {
 					};
 
 					let textEdits: vscode.TextEdit[] = [];
-					let filePatch = canFormatToolUseDiff ? getEditsFromUnifiedDiffStr(stdout)[0] : getEdits(filename, document.getText(), stdout);
+					let filePatch = canFormatToolUseDiff ? getEditsFromUnifiedDiffStr(stdout)[0] : getEdits(filename, documentText, stdout);
 
 					filePatch.edits.forEach((edit) => {
 						textEdits.push(edit.apply());
@@ -54,6 +55,7 @@ export class Formatter {
 					reject('Internal issues while getting diff from formatted content');
 				}
 			});
+			process.stdin.end(documentText);
 		});
 	}
 }
@@ -66,9 +68,7 @@ export class GoDocumentFormattingEditProvider implements vscode.DocumentFormatti
 	}
 
 	public provideDocumentFormattingEdits(document: vscode.TextDocument, options: vscode.FormattingOptions, token: vscode.CancellationToken): Thenable<vscode.TextEdit[]> {
-		return document.save().then(() => {
-			return this.formatter.formatDocument(document);
-		});
+		return this.formatter.formatDocument(document);
 	}
 }
 
diff --git a/src/goMain.ts b/src/goMain.ts
index b3f7c9ce8..aceb49177 100644
--- a/src/goMain.ts
+++ b/src/goMain.ts
@@ -95,6 +95,7 @@ export function activate(ctx: vscode.ExtensionContext): void {
 	vscode.window.onDidChangeActiveTextEditor(getCodeCoverage, null, ctx.subscriptions);
 	vscode.workspace.onDidChangeTextDocument(parseLiveFile, null, ctx.subscriptions);
 
+	formatOnSaveWatcher(ctx.subscriptions);
 	startBuildOnSaveWatcher(ctx.subscriptions);
 
 	ctx.subscriptions.push(vscode.commands.registerCommand('go.gopath', () => {
@@ -302,41 +303,29 @@ function runBuilds(document: vscode.TextDocument, goConfig: vscode.WorkspaceConf
 	});
 }
 
-function startBuildOnSaveWatcher(subscriptions: vscode.Disposable[]) {
-
-	// TODO: This is really ugly.  I'm not sure we can do better until
-	// Code supports a pre-save event where we can do the formatting before
-	// the file is written to disk.
-	let ignoreNextSave = new WeakSet<vscode.TextDocument>();
-
-	vscode.workspace.onDidSaveTextDocument(document => {
-		if (document.languageId !== 'go' || ignoreNextSave.has(document)) {
+function formatOnSaveWatcher(subscriptions: vscode.Disposable[]) {
+	vscode.workspace.onWillSaveTextDocument(event => {
+		let document = event.document;
+		if (document.languageId !== 'go') {
 			return;
 		}
 		let goConfig = vscode.workspace.getConfiguration('go');
 		let textEditor = vscode.window.activeTextEditor;
-		let formatPromise: PromiseLike<void> = Promise.resolve();
 		if (goConfig['formatOnSave'] && textEditor.document === document) {
 			let formatter = new Formatter();
-			formatPromise = formatter.formatDocument(document).then(edits => {
-				return textEditor.edit(editBuilder => {
-					edits.forEach(edit => editBuilder.replace(edit.range, edit.newText));
-				});
-			}).then(applied => {
-				ignoreNextSave.add(document);
-				return document.save();
-			}).then(() => {
-				ignoreNextSave.delete(document);
-			}, () => {
-				// Catch any errors and ignore so that we still trigger
-				// the file save.
-			});
+			event.waitUntil(formatter.formatDocument(document));
 		}
-		formatPromise.then(() => {
-			runBuilds(document, goConfig);
-		});
 	}, null, subscriptions);
+}
 
+function startBuildOnSaveWatcher(subscriptions: vscode.Disposable[]) {
+	vscode.workspace.onDidSaveTextDocument(document => {
+		if (document.languageId !== 'go') {
+			return;
+		}
+		let goConfig = vscode.workspace.getConfiguration('go');
+		runBuilds(document, goConfig);
+	}, null, subscriptions);
 }
 
 function sendTelemetryEventForConfig(goConfig: vscode.WorkspaceConfiguration) {