Factor out RawFileSystem. (#9499)

(for #8995)

This separates the low-level filesystem operations from the high-level "fs utils". The move to the VS Code FS API can then happen strictly inside RawFileSystem. Also, this is part of what we reverted in #8970.

Note that the bulk of the changes are in test code. Also, of the non-test code, the changes are either just moving things around (from FileSystem to RawFileSystem), or adding the new RawFileSystem class (and IRawFileSystem interface).

Author: ericsnowcurrently

src/client/common/platform/fileSystem.ts

@@ -91,8 +91,57 @@ export interface IFileSystemPathUtils {
 
 export import FileType = vscode.FileType;
 export import FileStat = vscode.FileStat;
+export type ReadStream = fs.ReadStream;
 export type WriteStream = fs.WriteStream;
 
+// The low-level filesystem operations on which the extension depends.
+export interface IRawFileSystem {
+    // Get information about a file (resolve symlinks).
+    stat(filename: string): Promise<FileStat>;
+    // Get information about a file (do not resolve synlinks).
+    lstat(filename: string): Promise<FileStat>;
+    // Change a file's permissions.
+    chmod(filename: string, mode: string | number): Promise<void>;
+    // Move the file to a different location (and/or rename it).
+    move(src: string, tgt: string): Promise<void>;
+
+    //***********************
+    // files
+
+    // Return the raw bytes of the given file.
+    readData(filename: string): Promise<Buffer>;
+    // Return the text of the given file (decoded from UTF-8).
+    readText(filename: string): Promise<string>;
+    // Write the given text to the file (UTF-8 encoded).
+    writeText(filename: string, data: {}): Promise<void>;
+    // Write the given text to the end of the file (UTF-8 encoded).
+    appendText(filename: string, text: string): Promise<void>;
+    // Copy a file.
+    copyFile(src: string, dest: string): Promise<void>;
+    // Delete a file.
+    rmfile(filename: string): Promise<void>;
+
+    //***********************
+    // directories
+
+    // Create the directory and any missing parent directories.
+    mkdirp(dirname: string): Promise<void>;
+    // Delete the directory and everything in it.
+    rmtree(dirname: string): Promise<void>;
+    // Return the contents of the directory.
+    listdir(dirname: string): Promise<[string, FileType][]>;
+
+    //***********************
+    // not async
+
+    // Return the text of the given file (decoded from UTF-8).
+    readTextSync(filename: string): string;
+    // Create a streaming wrappr around an open file (for reading).
+    createReadStream(filename: string): ReadStream;
+    // Create a streaming wrappr around an open file (for writing).
+    createWriteStream(filename: string): WriteStream;
+}
+
 export const IFileSystem = Symbol('IFileSystem');
 export interface IFileSystem {
     // path-related
@@ -106,8 +155,8 @@ export interface IFileSystem {
     listdir(dirname: string): Promise<[string, FileType][]>;
     readFile(filePath: string): Promise<string>;
     readData(filePath: string): Promise<Buffer>;
-    writeFile(filePath: string, data: {}, options?: string | fsextra.WriteFileOptions): Promise<void>;
-    appendFile(filename: string, data: {}): Promise<void>;
+    writeFile(filePath: string, text: string | Buffer, options?: string | fsextra.WriteFileOptions): Promise<void>;
+    appendFile(filename: string, text: string | Buffer): Promise<void>;
     copyFile(src: string, dest: string): Promise<void>;
     deleteFile(filename: string): Promise<void>;
     chmod(path: string, mode: string | number): Promise<void>;