From abc0784e57610a0cceca63301489918015418df6 Mon Sep 17 00:00:00 2001
From: Ryan Cumming <etaoins@gmail.com>
Date: Thu, 27 Jun 2019 21:30:23 +1000
Subject: Fix `cargo watch` code action filtering

There are two issues with the implementation of `provideCodeActions`
introduced in #1439:

1. We're returning the code action based on the file its diagnostic is
   in; not the file the suggested fix is in. I'm not sure how often
   fixes are suggested cross-file but it's something we should handle.

2. We're not filtering code actions based on the passed range. The means
   if there is any suggestion in a file we'll show an action for every
   line of the file. I naively thought that VS Code would filter for us
   but that was wrong.

Unfortunately the VS Code `CodeAction` object is very complex - it can
handle edits across multiple files, run commands, etc. This makes it
complex to check them for equality or see if any of their edits
intersects with a specified range.

To make it easier to work with suggestions this introduces a
`SuggestedFix` model object and a `SuggestFixCollection` code action
provider. This is a layer between the raw Rust JSON and VS Code's
`CodeAction`s. I was reluctant to introduce another layer of abstraction
here but my attempt to work directly with VS Code's model objects was
worse.
---
 editors/code/src/utils/diagnostics/SuggestedFix.ts | 67 ++++++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 editors/code/src/utils/diagnostics/SuggestedFix.ts

(limited to 'editors/code/src/utils/diagnostics/SuggestedFix.ts')

diff --git a/editors/code/src/utils/diagnostics/SuggestedFix.ts b/editors/code/src/utils/diagnostics/SuggestedFix.ts
new file mode 100644
index 000000000..b1be2a225
--- /dev/null
+++ b/editors/code/src/utils/diagnostics/SuggestedFix.ts
@@ -0,0 +1,67 @@
+import * as vscode from 'vscode';
+
+import { SuggestionApplicability } from './rust';
+
+/**
+ * Model object for text replacements suggested by the Rust compiler
+ *
+ * This is an intermediate form between the raw `rustc` JSON and a
+ * `vscode.CodeAction`. It's optimised for the use-cases of
+ * `SuggestedFixCollection`.
+ */
+export default class SuggestedFix {
+    public readonly title: string;
+    public readonly location: vscode.Location;
+    public readonly replacement: string;
+    public readonly applicability: SuggestionApplicability;
+
+    /**
+     * Diagnostics this suggested fix could resolve
+     */
+    public diagnostics: vscode.Diagnostic[];
+
+    constructor(
+        title: string,
+        location: vscode.Location,
+        replacement: string,
+        applicability: SuggestionApplicability = SuggestionApplicability.Unspecified
+    ) {
+        this.title = title;
+        this.location = location;
+        this.replacement = replacement;
+        this.applicability = applicability;
+        this.diagnostics = [];
+    }
+
+    /**
+     * Determines if this suggested fix is equivalent to another instance
+     */
+    public isEqual(other: SuggestedFix): boolean {
+        return (
+            this.title === other.title &&
+            this.location.range.isEqual(other.location.range) &&
+            this.replacement === other.replacement &&
+            this.applicability === other.applicability
+        );
+    }
+
+    /**
+     * Converts this suggested fix to a VS Code Quick Fix code action
+     */
+    public toCodeAction(): vscode.CodeAction {
+        const codeAction = new vscode.CodeAction(
+            this.title,
+            vscode.CodeActionKind.QuickFix
+        );
+
+        const edit = new vscode.WorkspaceEdit();
+        edit.replace(this.location.uri, this.location.range, this.replacement);
+        codeAction.edit = edit;
+
+        codeAction.isPreferred =
+            this.applicability === SuggestionApplicability.MachineApplicable;
+
+        codeAction.diagnostics = [...this.diagnostics];
+        return codeAction;
+    }
+}
-- 
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