cache decoded android library in globalStoragePath

extension.js

@@ -11,6 +11,9 @@ const { selectTargetDevice } = require('./src/utils/device');
 /** @type {LanguageClient} */
 let client;
 
+/**
+ * @param {vscode.ExtensionContext} context
+ */
 function activateLanguageClient(context) {
   // The server is implemented in node
   let serverModule = context.asAbsolutePath(path.join('langserver', 'server.js'));
@@ -38,10 +41,14 @@ function activateLanguageClient(context) {
   let clientOptions = {
     // Register the server for plain text documents
     documentSelector: [{ scheme: 'file', language: 'java' }],
+    initializationOptions: {
+        // globalStoragePath is used to cache decoded jar files
+        globalStoragePath: context.globalStoragePath,
+    },
     synchronize: {
       // Notify the server about file changes to '.java files contained in the workspace
       fileEvents: vscode.workspace.createFileSystemWatcher('**/.java')
-    }
+    },
   };
 
   // Create the language client and start the client.

langserver/java/java-libraries.js

@@ -0,0 +1,174 @@
+const fs = require('fs');
+const path = require('path');
+const { loadAndroidLibrary, CEIType } = require('java-mti');
+
+const android_system_library_cache_filename = {
+    regex: /^sdk-platforms-android-(.+?)-(\d+)\.json$/,
+    /**
+     * @param {string} version
+     * @param {fs.Stats} stat 
+     */
+    build(version, stat) {
+        return `sdk-platforms-${version}-${Math.trunc(stat.mtime.getTime())}.json`;
+    }
+}
+
+/**
+ * @param {string} cache_dir directory used to store decoded jar libraries
+ */
+function ensureFolderExists(cache_dir) {
+    if (!cache_dir) {
+        throw new Error('missing cache dir value');
+    }
+    try {
+        const stat = fs.statSync(cache_dir);
+        if (!stat.isDirectory()) {
+            throw new Error(`cache dir '${cache_dir}' is not a directory`);
+        }
+    } catch (err) {
+        if (err.code !== 'ENOENT') {
+            throw new Error(`cache dir '${cache_dir}' check failed: ${err.message}`);
+        }
+        fs.mkdirSync(cache_dir);
+    }
+}
+
+/**
+ * 
+ * @param {string} cache_dir 
+ * @param {RegExp} filter 
+ * @returns {fs.Dirent[]}
+ */
+function findLibraryFiles(cache_dir, filter) {
+    const files = fs.readdirSync(cache_dir, { withFileTypes: true });
+    const valid_files = files.filter(file =>  filter.test(file.name) && file.isFile());
+    return valid_files;
+}
+
+/**
+ * 
+ * @param {fs.Dirent[]} files 
+ */
+function chooseAndroidSystemLibrary(files) {
+    let chosen = {
+        api: 0,
+        /** @type {fs.Dirent} */
+        file: null,
+    };
+    files.forEach(file => {
+        const m = file.name.match(android_system_library_cache_filename.regex);
+        if (!m) return;
+        if (/^\d+$/.test(m[1])) {
+            const api = parseInt(m[1]);
+            if (api > chosen.api) {
+                chosen.api = api;
+                chosen.file = file;
+            }
+        }
+    })
+    return chosen.file;
+}
+
+function findHighestAPISystemLibrary(android_sdk_platforms_root) {
+    let platform_folders = [], android_platform_jars = [];
+    try {
+        platform_folders = fs.readdirSync(android_sdk_platforms_root, { withFileTypes: true });
+    } catch {};
+    platform_folders.forEach(folder => {
+        if (!folder.isDirectory()) return;
+        // we assume stable SDK platform folders are named 'android-<api-level>'
+        if (!/^android-\d+$/.test(folder.name)) return;
+        // the platform folder must contain an android.jar file
+        let stat, filepath = path.join(android_sdk_platforms_root, folder.name, 'android.jar');
+        try { stat = fs.statSync(filepath) }
+        catch { return }
+        if (!stat.isFile()) return;
+        // add it to the list
+        android_platform_jars.push({
+            folder: folder.name,
+            api: parseInt(folder.name.split('-')[1], 10),
+            filepath,
+            stat,
+        })
+    });
+    if (android_platform_jars.length === 0) {
+        return null;
+    }
+    // choose the folder with the highest API number
+    return android_platform_jars.sort((a,b) => b.api - a.api)[0].folder;
+}
+
+/**
+ * @param {string} cache_dir
+ * @param {string|':latest'} [version] 
+ */
+async function buildAndroidSystemLibrary(cache_dir, version) {
+    const android_sdk_root = process.env['ANDROID_SDK'] || process.env['ANDROID_HOME'];
+    if (!android_sdk_root) {
+        throw new Error('Cannot locate Android SDK folder - ANDROID_SDK env variable is not defined');
+    }
+    const android_sdk_platforms_root = path.join(android_sdk_root, 'platforms');
+
+    if (!version) {
+        // choose the folder with the highest API number
+        version = findHighestAPISystemLibrary(android_sdk_platforms_root);
+        if (!version) {
+            throw new Error(`Cannot build Android library: No supported system libraries found in ${android_sdk_platforms_root}`);
+        }
+    }
+
+    let stat, filepath = path.join(android_sdk_platforms_root, version, 'android.jar');
+    try { stat = fs.statSync(filepath) }
+    catch { }
+    if (!stat || !stat.isFile()) {
+        throw new Error(`Cannot build Android library: '${filepath}' is not a valid android system library file`);
+    }
+
+    console.log(`Building ${version} library cache for code completion support. This might take a few minutes...`);
+    const cache_filename = path.join(cache_dir, android_system_library_cache_filename.build(version, stat));
+    try {
+        const library = await loadAndroidLibrary(cache_filename, { api: version, sdk_root: android_sdk_root });
+        console.log(`${version} library cache built.`);
+        return library;
+    } catch(err) {
+        throw new Error(`Cannot build Android library: ${err.message}`);
+    }
+}
+
+/**
+ * @param {string} cache_dir directory used to store decoded jar libraries
+ * @returns {Promise<Map<string,CEIType>>}
+ */
+async function loadAndroidSystemLibrary(cache_dir) {
+    console.time('android-library-load');
+    // for (let x;;) {
+    //     console.log('waiting');
+    //     if (x) break;
+    //     await new Promise(res => setTimeout(res, 1000));
+    // }
+    let library;
+    try {
+        ensureFolderExists(cache_dir);
+        const library_files = findLibraryFiles(cache_dir, android_system_library_cache_filename.regex);
+        if (!library_files.length) {
+            return buildAndroidSystemLibrary(cache_dir);
+        }
+        // search for the highest android API number in the list of cached files
+        const library_file = chooseAndroidSystemLibrary(library_files);
+        if (!library_file) {
+            return buildAndroidSystemLibrary(cache_dir);
+        }
+        // load the library
+        const library_path_name = path.join(cache_dir, library_file.name);
+        console.log(`Loading android system library: ${library_path_name}`);
+        library = await loadAndroidLibrary(library_path_name, null);
+
+    } catch (err) {
+        console.error(`android library load failed: ${err.message}`);
+        library = new Map();
+    }
+    console.timeEnd('android-library-load');
+    return library;
+}
+
+exports.loadAndroidSystemLibrary = loadAndroidSystemLibrary;

langserver/server.js

@@ -18,7 +18,8 @@ const {
 
 const { TextDocument } = require('vscode-languageserver-textdocument');
 
-const { loadAndroidLibrary, JavaType, CEIType, ArrayType, PrimitiveType, Method } = require('java-mti');
+const { loadAndroidSystemLibrary } = require('./java/java-libraries');
+const { JavaType, CEIType, ArrayType, PrimitiveType, Method } = require('java-mti');
 
 const { ParseProblem } = require('./java/parser');
 const { parse } = require('./java/body-parser3');
@@ -289,14 +290,16 @@ let hasWorkspaceFolderCapability = false;
 let hasDiagnosticRelatedInformationCapability = false;
 
 connection.onInitialize((params) => {
-    console.time('android-library-load')
-    androidLibrary = loadAndroidLibrary('android-25').then(lib => {
-            console.timeEnd('android-library-load')
-            return androidLibrary = lib;
-    }, err => {
-        trace(`android library load failed: ${err.message}`);
-        return androidLibrary = new Map();
-    });
+
+    // the storage path is passed to us by the client side of the extension
+    const library_cache_path = (params.initializationOptions || {}).globalStoragePath;
+    trace(`library_cache_path: ${library_cache_path}`);
+
+    // the android library is loaded asynchronously, with the global `androidLibrary` variable
+    // set to the promise while it is loading.
+    androidLibrary = loadAndroidSystemLibrary(library_cache_path)
+        .then(library => androidLibrary = library);
+
     let capabilities = params.capabilities;
 
     // Does the client support the `workspace/configuration` request?