avoid recomputing project roots and ReScript versions as much as possible

Author: zth

server/src/projectFiles.ts

@@ -0,0 +1,25 @@
+import * as cp from "node:child_process";
+import * as p from "vscode-languageserver-protocol";
+
+export type filesDiagnostics = {
+  [key: string]: p.Diagnostic[];
+};
+
+interface projectFiles {
+  openFiles: Set<string>;
+  filesWithDiagnostics: Set<string>;
+  filesDiagnostics: filesDiagnostics;
+  rescriptVersion: string | undefined;
+
+  bsbWatcherByEditor: null | cp.ChildProcess;
+
+  // This keeps track of whether we've prompted the user to start a build
+  // automatically, if there's no build currently running for the project. We
+  // only want to prompt the user about this once, or it becomes
+  // annoying.
+  // The type `never` means that we won't show the prompt if the project is inside node_modules
+  hasPromptedToStartBuild: boolean | "never";
+}
+
+export let projectsFiles: Map<string, projectFiles> = // project root path
+  new Map();

server/src/server.ts

@@ -22,12 +22,11 @@ import * as c from "./constants";
 import * as chokidar from "chokidar";
 import { assert } from "console";
 import { fileURLToPath } from "url";
-import * as cp from "node:child_process";
 import { WorkspaceEdit } from "vscode-languageserver";
-import { filesDiagnostics } from "./utils";
 import { onErrorReported } from "./errorReporter";
 import * as ic from "./incrementalCompilation";
 import config, { extensionConfiguration } from "./config";
+import { projectsFiles } from "./projectFiles";
 
 // This holds client capabilities specific to our extension, and not necessarily
 // related to the LS protocol. It's for enabling/disabling features that might
@@ -49,23 +48,7 @@ let serverSentRequestIdCounter = 0;
 // https://microsoft.github.io/language-server-protocol/specification#exit
 let shutdownRequestAlreadyReceived = false;
 let stupidFileContentCache: Map<string, string> = new Map();
-let projectsFiles: Map<
-  string, // project root path
-  {
-    openFiles: Set<string>;
-    filesWithDiagnostics: Set<string>;
-    filesDiagnostics: filesDiagnostics;
-
-    bsbWatcherByEditor: null | cp.ChildProcess;
-
-    // This keeps track of whether we've prompted the user to start a build
-    // automatically, if there's no build currently running for the project. We
-    // only want to prompt the user about this once, or it becomes
-    // annoying.
-    // The type `never` means that we won't show the prompt if the project is inside node_modules
-    hasPromptedToStartBuild: boolean | "never";
-  }
-> = new Map();
+
 // ^ caching AND states AND distributed system. Why does LSP has to be stupid like this
 
 // This keeps track of code actions extracted from diagnostics.
@@ -246,6 +229,7 @@ let openedFile = (fileUri: string, fileContent: string) => {
         openFiles: new Set(),
         filesWithDiagnostics: new Set(),
         filesDiagnostics: {},
+        rescriptVersion: utils.findReScriptVersion(projectRootPath),
         bsbWatcherByEditor: null,
         hasPromptedToStartBuild: /(\/|\\)node_modules(\/|\\)/.test(
           projectRootPath

server/src/utils.ts

@@ -14,6 +14,7 @@ import * as c from "./constants";
 import * as lookup from "./lookup";
 import { reportError } from "./errorReporter";
 import config from "./config";
+import { filesDiagnostics, projectsFiles } from "./projectFiles";
 
 let tempFilePrefix = "rescript_format_file_" + process.pid + "_";
 let tempFileId = 0;
@@ -24,9 +25,7 @@ export let createFileInTempDir = (extension = "") => {
   return path.join(os.tmpdir(), tempFileName);
 };
 
-// TODO: races here?
-// TODO: this doesn't handle file:/// scheme
-export let findProjectRootOfFile = (
+let findProjectRootOfFileInDir = (
   source: p.DocumentUri
 ): null | p.DocumentUri => {
   let dir = path.dirname(source);
@@ -40,11 +39,37 @@ export let findProjectRootOfFile = (
       // reached top
       return null;
     } else {
-      return findProjectRootOfFile(dir);
+      return findProjectRootOfFileInDir(dir);
     }
   }
 };
 
+// TODO: races here?
+// TODO: this doesn't handle file:/// scheme
+export let findProjectRootOfFile = (
+  source: p.DocumentUri
+): null | p.DocumentUri => {
+  // First look in project files
+  let foundRootFromProjectFiles: string | null = null;
+
+  for (const rootPath of projectsFiles.keys()) {
+    if (source.startsWith(rootPath)) {
+      // Prefer the longest path (most nested)
+      if (
+        foundRootFromProjectFiles == null ||
+        rootPath.length > foundRootFromProjectFiles.length
+      )
+        foundRootFromProjectFiles = rootPath;
+    }
+  }
+
+  if (foundRootFromProjectFiles != null) {
+    return foundRootFromProjectFiles;
+  } else {
+    return findProjectRootOfFileInDir(source);
+  }
+};
+
 // Check if binaryName exists inside binaryDirPath and return the joined path.
 export let findBinary = (
   binaryDirPath: p.DocumentUri | null,
@@ -138,7 +163,9 @@ export let formatCode = (
   }
 };
 
-let findReScriptVersion = (filePath: p.DocumentUri): string | undefined => {
+export let findReScriptVersion = (
+  filePath: p.DocumentUri
+): string | undefined => {
   let projectRoot = findProjectRootOfFile(filePath);
   if (projectRoot == null) {
     return undefined;
@@ -161,25 +188,31 @@ let findReScriptVersion = (filePath: p.DocumentUri): string | undefined => {
   }
 };
 
+let binaryPath: string | null = null;
+if (fs.existsSync(c.analysisDevPath)) {
+  binaryPath = c.analysisDevPath;
+} else if (fs.existsSync(c.analysisProdPath)) {
+  binaryPath = c.analysisProdPath;
+} else {
+}
+
 export let runAnalysisAfterSanityCheck = (
   filePath: p.DocumentUri,
   args: Array<any>,
   projectRequired = false
 ) => {
-  let binaryPath;
-  if (fs.existsSync(c.analysisDevPath)) {
-    binaryPath = c.analysisDevPath;
-  } else if (fs.existsSync(c.analysisProdPath)) {
-    binaryPath = c.analysisProdPath;
-  } else {
+  if (binaryPath == null) {
     return null;
   }
 
   let projectRootPath = findProjectRootOfFile(filePath);
   if (projectRootPath == null && projectRequired) {
     return null;
   }
-  let rescriptVersion = findReScriptVersion(filePath);
+  let rescriptVersion =
+    projectsFiles.get(projectRootPath ?? "")?.rescriptVersion ??
+    findReScriptVersion(filePath);
+
   let options: childProcess.ExecFileSyncOptions = {
     cwd: projectRootPath || undefined,
     maxBuffer: Infinity,
@@ -445,9 +478,6 @@ let parseFileAndRange = (fileAndRange: string) => {
 };
 
 // main parsing logic
-export type filesDiagnostics = {
-  [key: string]: p.Diagnostic[];
-};
 type parsedCompilerLogResult = {
   done: boolean;
   result: filesDiagnostics;