Merge #5917

5917: Add a command to open docs for the symbol under the cursor r=matklad a=zacps

#### Todo

- [ ] Decide if there should be a default keybind or context menu entry
- [x] Figure out how to get the documentation path for methods and other non-top-level defs
- [x] Design the protocol extension. In future we'll probably want parameters for local/remote documentation URLs, so that should maybe be done in this PR?
- [x] Code organisation
- [x] Tests


Co-authored-by: Zac Pullar-Strecker <[email protected]>

4 files changed, 35 insertions, 2 deletions

diff --git a/editors/code/package.json b/editors/code/package.json
index 6a712a8a8..4bd3117fc 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json
@@ -182,6 +182,11 @@
                 "command": "rust-analyzer.toggleInlayHints",
                 "title": "Toggle inlay hints",
                 "category": "Rust Analyzer"
+            },
+            {
+                "command": "rust-analyzer.openDocs",
+                "title": "Open docs under cursor",
+                "category": "Rust Analyzer"
             }
         ],
         "keybindings": [
@@ -1044,6 +1049,10 @@
                 {
                     "command": "rust-analyzer.toggleInlayHints",
                     "when": "inRustProject"
+                },
+                {
+                    "command": "rust-analyzer.openDocs",
+                    "when": "inRustProject"
                 }
             ]
         }
diff --git a/editors/code/src/commands.ts b/editors/code/src/commands.ts
index 1a90f1b7d..1445e41d3 100644
--- a/editors/code/src/commands.ts
+++ b/editors/code/src/commands.ts
@@ -419,10 +419,31 @@ export function gotoLocation(ctx: Ctx): Cmd {
     };
 }
 
+export function openDocs(ctx: Ctx): Cmd {
+    return async () => {
+
+        const client = ctx.client;
+        const editor = vscode.window.activeTextEditor;
+        if (!editor || !client) {
+            return;
+        };
+
+        const position = editor.selection.active;
+        const textDocument = { uri: editor.document.uri.toString() };
+
+        const doclink = await client.sendRequest(ra.openDocs, { position, textDocument });
+
+        if (doclink != null) {
+            vscode.commands.executeCommand("vscode.open", vscode.Uri.parse(doclink));
+        }
+    };
+
+}
+
 export function resolveCodeAction(ctx: Ctx): Cmd {
     const client = ctx.client;
-    return async (params: ra.ResolveCodeActionParams) => {
-        const item: lc.WorkspaceEdit = await client.sendRequest(ra.resolveCodeAction, params);
+    return async () => {
+        const item: lc.WorkspaceEdit = await client.sendRequest(ra.resolveCodeAction, null);
         if (!item) {
             return;
         }
diff --git a/editors/code/src/lsp_ext.ts b/editors/code/src/lsp_ext.ts
index f286b68a6..fc8e120b3 100644
--- a/editors/code/src/lsp_ext.ts
+++ b/editors/code/src/lsp_ext.ts
@@ -118,3 +118,5 @@ export interface CommandLinkGroup {
     title?: string;
     commands: CommandLink[];
 }
+
+export const openDocs = new lc.RequestType<lc.TextDocumentPositionParams, string | void, void>('experimental/externalDocs');
diff --git a/editors/code/src/main.ts b/editors/code/src/main.ts
index 2896d90ac..09543e348 100644
--- a/editors/code/src/main.ts
+++ b/editors/code/src/main.ts
@@ -110,6 +110,7 @@ async function tryActivate(context: vscode.ExtensionContext) {
     ctx.registerCommand('run', commands.run);
     ctx.registerCommand('debug', commands.debug);
     ctx.registerCommand('newDebugConfig', commands.newDebugConfig);
+    ctx.registerCommand('openDocs', commands.openDocs);
 
     defaultOnEnter.dispose();
     ctx.registerCommand('onEnter', commands.onEnter);