debug: initial work on memory support

This implements the core memory "model" for debugging that reflects
DAP, in `debugModel.ts`. It also implements a filesystem provider based
on that in `debugMemory.ts`, for tentative application in the hex editor.

Finally it adds context menu items for these. This works with changes in
mock debug, but for some reason reopening the ".bin" file in the hex
editor results in a blank editor. Still need to look at that.

Ultimately though, as indicated in #126268, we'll probably want custom
commands for the hex editor to call as low level read/write is not
supported in the stable API. Also, the file API doesn't represent the
"unreadable" ranges which DAP supports.

Author: connor4312

src/vs/base/common/buffer.ts

@@ -284,3 +284,104 @@ export function prefixedBufferReadable(prefix: VSBuffer, readable: VSBufferReada
 export function prefixedBufferStream(prefix: VSBuffer, stream: VSBufferReadableStream): VSBufferReadableStream {
 	return streams.prefixedStream(prefix, stream, chunks => VSBuffer.concat(chunks));
 }
+
+/** Decodes base64 to a uint8 array. URL-encoded and unpadded base64 is allowed. */
+export function decodeBase64(encoded: string) {
+	let building = 0;
+	let remainder = 0;
+	let bufi = 0;
+
+	// The simpler way to do this is `Uint8Array.from(atob(str), c => c.charCodeAt(0))`,
+	// but that's about 10-20x slower than this function in current Chromium versions.
+
+	const buffer = new Uint8Array(Math.floor(encoded.length / 4 * 3));
+	const append = (value: number) => {
+		switch (remainder) {
+			case 3:
+				buffer[bufi++] = building | value;
+				remainder = 0;
+				break;
+			case 2:
+				buffer[bufi++] = building | (value >>> 2);
+				building = value << 6;
+				remainder = 3;
+				break;
+			case 1:
+				buffer[bufi++] = building | (value >>> 4);
+				building = value << 4;
+				remainder = 2;
+				break;
+			default:
+				building = value << 2;
+				remainder = 1;
+		}
+	};
+
+	for (let i = 0; i < encoded.length; i++) {
+		const code = encoded.charCodeAt(i);
+		// See https://datatracker.ietf.org/doc/html/rfc4648#section-4
+		// This branchy code is about 3x faster than an indexOf on a base64 char string.
+		if (code >= 65 && code <= 90) {
+			append(code - 65); // A-Z starts ranges from char code 65 to 90
+		} else if (code >= 97 && code <= 122) {
+			append(code - 97 + 26); // a-z starts ranges from char code 97 to 122, starting at byte 26
+		} else if (code >= 48 && code <= 57) {
+			append(code - 48 + 52); // 0-9 starts ranges from char code 48 to 58, starting at byte 52
+		} else if (code === 43 || code === 45) {
+			append(62); // "+" or "-" for URLS
+		} else if (code === 47 || code === 95) {
+			append(63); // "/" or "_" for URLS
+		} else if (code === 61) {
+			break; // "="
+		} else {
+			throw new SyntaxError(`Unexpected base64 character ${encoded[i]}`);
+		}
+	}
+
+	const unpadded = bufi;
+	while (remainder > 0) {
+		append(0);
+	}
+
+	// slice is needed to account for overestimation due to padding
+	return VSBuffer.wrap(buffer).slice(0, unpadded);
+}
+
+const base64Alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
+const base64UrlSafeAlphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_';
+
+/** Encodes a buffer to a base64 string. */
+export function encodeBase64({ buffer }: VSBuffer, padded = true, urlSafe = false) {
+	const dictionary = urlSafe ? base64UrlSafeAlphabet : base64Alphabet;
+	let output = '';
+
+	const remainder = buffer.byteLength % 3;
+
+	let i = 0;
+	for (; i < buffer.byteLength - remainder; i += 3) {
+		const a = buffer[i + 0];
+		const b = buffer[i + 1];
+		const c = buffer[i + 2];
+
+		output += dictionary[a >>> 2];
+		output += dictionary[(a << 4 | b >>> 4) & 0b111111];
+		output += dictionary[(b << 2 | c >>> 6) & 0b111111];
+		output += dictionary[c & 0b111111];
+	}
+
+	if (remainder === 1) {
+		const a = buffer[i + 0];
+		output += dictionary[a >>> 2];
+		output += dictionary[(a << 4) & 0b111111];
+		if (padded) { output += '=='; }
+	} else if (remainder === 2) {
+		const a = buffer[i + 0];
+		const b = buffer[i + 1];
+		output += dictionary[a >>> 2];
+		output += dictionary[(a << 4 | b >>> 4) & 0b111111];
+		output += dictionary[(b << 2) & 0b111111];
+		if (padded) { output += '='; }
+	}
+
+	return output;
+}

src/vs/base/test/common/buffer.test.ts

@@ -5,7 +5,7 @@
 
 import * as assert from 'assert';
 import { timeout } from 'vs/base/common/async';
-import { bufferedStreamToBuffer, bufferToReadable, bufferToStream, newWriteableBufferStream, readableToBuffer, streamToBuffer, VSBuffer } from 'vs/base/common/buffer';
+import { bufferedStreamToBuffer, bufferToReadable, bufferToStream, decodeBase64, encodeBase64, newWriteableBufferStream, readableToBuffer, streamToBuffer, VSBuffer } from 'vs/base/common/buffer';
 import { peekStream } from 'vs/base/common/stream';
 
 suite('Buffer', () => {
@@ -412,4 +412,53 @@ suite('Buffer', () => {
 			assert.strictEqual(u2[0], 17);
 		}
 	});
+
+	suite('base64', () => {
+		/*
+		Generated with:
+
+		const crypto = require('crypto');
+
+		for (let i = 0; i < 16; i++) {
+			const buf =  crypto.randomBytes(i);
+			console.log(`[new Uint8Array([${Array.from(buf).join(', ')}]), '${buf.toString('base64')}'],`)
+		}
+
+		*/
+
+		const testCases: [Uint8Array, string][] = [
+			[new Uint8Array([]), ''],
+			[new Uint8Array([56]), 'OA=='],
+			[new Uint8Array([209, 4]), '0QQ='],
+			[new Uint8Array([19, 57, 119]), 'Ezl3'],
+			[new Uint8Array([199, 237, 207, 112]), 'x+3PcA=='],
+			[new Uint8Array([59, 193, 173, 26, 242]), 'O8GtGvI='],
+			[new Uint8Array([81, 226, 95, 231, 116, 126]), 'UeJf53R+'],
+			[new Uint8Array([11, 164, 253, 85, 8, 6, 56]), 'C6T9VQgGOA=='],
+			[new Uint8Array([164, 16, 88, 88, 224, 173, 144, 114]), 'pBBYWOCtkHI='],
+			[new Uint8Array([0, 196, 99, 12, 21, 229, 78, 101, 13]), 'AMRjDBXlTmUN'],
+			[new Uint8Array([167, 114, 225, 116, 226, 83, 51, 48, 88, 114]), 'p3LhdOJTMzBYcg=='],
+			[new Uint8Array([75, 33, 118, 10, 77, 5, 168, 194, 59, 47, 59]), 'SyF2Ck0FqMI7Lzs='],
+			[new Uint8Array([203, 182, 165, 51, 208, 27, 123, 223, 112, 198, 127, 147]), 'y7alM9Abe99wxn+T'],
+			[new Uint8Array([154, 93, 222, 41, 117, 234, 250, 85, 95, 144, 16, 94, 18]), 'ml3eKXXq+lVfkBBeEg=='],
+			[new Uint8Array([246, 186, 88, 105, 192, 57, 25, 168, 183, 164, 103, 162, 243, 56]), '9rpYacA5Gai3pGei8zg='],
+			[new Uint8Array([149, 240, 155, 96, 30, 55, 162, 172, 191, 187, 33, 124, 169, 183, 254]), 'lfCbYB43oqy/uyF8qbf+'],
+		];
+
+		test('encodes', () => {
+			for (const [bytes, expected] of testCases) {
+				assert.strictEqual(encodeBase64(VSBuffer.wrap(bytes)), expected);
+			}
+		});
+
+		test('decodes', () => {
+			for (const [expected, encoded] of testCases) {
+				assert.deepStrictEqual(new Uint8Array(decodeBase64(encoded).buffer), expected);
+			}
+		});
+
+		test('throws error on invalid encoding', () => {
+			assert.throws(() => decodeBase64('invalid!'));
+		});
+	});
 });

src/vs/base/test/common/mock.ts

@@ -13,11 +13,11 @@ export function mock<T>(): Ctor<T> {
 	return function () { } as any;
 }
 
-export type MockObject<T, TP = {}> = { [K in keyof T]: K extends keyof TP ? TP[K] : SinonStub };
+export type MockObject<T, ExceptProps = never> = { [K in keyof T]: K extends ExceptProps ? T[K] : SinonStub };
 
 // Creates an object object that returns sinon mocks for every property. Optionally
 // takes base properties.
-export function mockObject<T extends object, TP extends Partial<T>>(properties?: TP): MockObject<T, TP> {
+export const mockObject = <T extends object>() => <TP extends Partial<T> = {}>(properties?: TP): MockObject<T, keyof TP> => {
 	return new Proxy({ ...properties } as any, {
 		get(target, key) {
 			if (!target.hasOwnProperty(key)) {
@@ -31,4 +31,4 @@ export function mockObject<T extends object, TP extends Partial<T>>(properties?:
 			return true;
 		},
 	});
-}
+};

src/vs/workbench/contrib/debug/browser/debug.contribution.ts

@@ -16,7 +16,7 @@ import { CallStackView } from 'vs/workbench/contrib/debug/browser/callStackView'
 import { Extensions as WorkbenchExtensions, IWorkbenchContributionsRegistry } from 'vs/workbench/common/contributions';
 import {
 	IDebugService, VIEWLET_ID, DEBUG_PANEL_ID, CONTEXT_IN_DEBUG_MODE, INTERNAL_CONSOLE_OPTIONS_SCHEMA,
-	CONTEXT_DEBUG_STATE, VARIABLES_VIEW_ID, CALLSTACK_VIEW_ID, WATCH_VIEW_ID, BREAKPOINTS_VIEW_ID, LOADED_SCRIPTS_VIEW_ID, CONTEXT_LOADED_SCRIPTS_SUPPORTED, CONTEXT_CALLSTACK_ITEM_TYPE, CONTEXT_RESTART_FRAME_SUPPORTED, CONTEXT_JUMP_TO_CURSOR_SUPPORTED, CONTEXT_DEBUG_UX, BREAKPOINT_EDITOR_CONTRIBUTION_ID, REPL_VIEW_ID, CONTEXT_BREAKPOINTS_EXIST, EDITOR_CONTRIBUTION_ID, CONTEXT_DEBUGGERS_AVAILABLE, CONTEXT_SET_VARIABLE_SUPPORTED, CONTEXT_BREAK_WHEN_VALUE_CHANGES_SUPPORTED, CONTEXT_VARIABLE_EVALUATE_NAME_PRESENT, getStateLabel, State, CONTEXT_WATCH_ITEM_TYPE, CONTEXT_STACK_FRAME_SUPPORTS_RESTART, CONTEXT_BREAK_WHEN_VALUE_IS_READ_SUPPORTED, CONTEXT_BREAK_WHEN_VALUE_IS_ACCESSED_SUPPORTED, CONTEXT_FOCUSED_SESSION_IS_ATTACH, CONTEXT_TERMINATE_DEBUGGEE_SUPPORTED, DISASSEMBLY_VIEW_ID, CONTEXT_SET_EXPRESSION_SUPPORTED, CONTEXT_VARIABLE_IS_READONLY,
+	CONTEXT_DEBUG_STATE, VARIABLES_VIEW_ID, CALLSTACK_VIEW_ID, WATCH_VIEW_ID, BREAKPOINTS_VIEW_ID, LOADED_SCRIPTS_VIEW_ID, CONTEXT_LOADED_SCRIPTS_SUPPORTED, CONTEXT_CALLSTACK_ITEM_TYPE, CONTEXT_RESTART_FRAME_SUPPORTED, CONTEXT_JUMP_TO_CURSOR_SUPPORTED, CONTEXT_DEBUG_UX, BREAKPOINT_EDITOR_CONTRIBUTION_ID, REPL_VIEW_ID, CONTEXT_BREAKPOINTS_EXIST, EDITOR_CONTRIBUTION_ID, CONTEXT_DEBUGGERS_AVAILABLE, CONTEXT_SET_VARIABLE_SUPPORTED, CONTEXT_BREAK_WHEN_VALUE_CHANGES_SUPPORTED, CONTEXT_VARIABLE_EVALUATE_NAME_PRESENT, getStateLabel, State, CONTEXT_WATCH_ITEM_TYPE, CONTEXT_STACK_FRAME_SUPPORTS_RESTART, CONTEXT_BREAK_WHEN_VALUE_IS_READ_SUPPORTED, CONTEXT_BREAK_WHEN_VALUE_IS_ACCESSED_SUPPORTED, CONTEXT_FOCUSED_SESSION_IS_ATTACH, CONTEXT_TERMINATE_DEBUGGEE_SUPPORTED, DISASSEMBLY_VIEW_ID, CONTEXT_SET_EXPRESSION_SUPPORTED, CONTEXT_VARIABLE_IS_READONLY, CONTEXT_CAN_VIEW_MEMORY,
 } from 'vs/workbench/contrib/debug/common/debug';
 import { DebugToolBar } from 'vs/workbench/contrib/debug/browser/debugToolBar';
 import { DebugService } from 'vs/workbench/contrib/debug/browser/debugService';
@@ -32,7 +32,7 @@ import { launchSchemaId } from 'vs/workbench/services/configuration/common/confi
 import { LoadedScriptsView } from 'vs/workbench/contrib/debug/browser/loadedScriptsView';
 import { RunToCursorAction } from 'vs/workbench/contrib/debug/browser/debugEditorActions';
 import { WatchExpressionsView, ADD_WATCH_LABEL, REMOVE_WATCH_EXPRESSIONS_COMMAND_ID, REMOVE_WATCH_EXPRESSIONS_LABEL, ADD_WATCH_ID } from 'vs/workbench/contrib/debug/browser/watchExpressionsView';
-import { VariablesView, SET_VARIABLE_ID, COPY_VALUE_ID, BREAK_WHEN_VALUE_CHANGES_ID, COPY_EVALUATE_PATH_ID, ADD_TO_WATCH_ID, BREAK_WHEN_VALUE_IS_ACCESSED_ID, BREAK_WHEN_VALUE_IS_READ_ID } from 'vs/workbench/contrib/debug/browser/variablesView';
+import { VariablesView, SET_VARIABLE_ID, COPY_VALUE_ID, BREAK_WHEN_VALUE_CHANGES_ID, COPY_EVALUATE_PATH_ID, ADD_TO_WATCH_ID, BREAK_WHEN_VALUE_IS_ACCESSED_ID, BREAK_WHEN_VALUE_IS_READ_ID, VIEW_MEMORY_ID } from 'vs/workbench/contrib/debug/browser/variablesView';
 import { Repl } from 'vs/workbench/contrib/debug/browser/repl';
 import { DebugContentProvider } from 'vs/workbench/contrib/debug/common/debugContentProvider';
 import { WelcomeView } from 'vs/workbench/contrib/debug/browser/welcomeView';
@@ -143,6 +143,7 @@ registerDebugViewMenuItem(MenuId.DebugCallStackContext, RESTART_FRAME_ID, nls.lo
 registerDebugViewMenuItem(MenuId.DebugCallStackContext, COPY_STACK_TRACE_ID, nls.localize('copyStackTrace', "Copy Call Stack"), 20, CONTEXT_CALLSTACK_ITEM_TYPE.isEqualTo('stackFrame'), undefined, '3_modification');
 
 registerDebugViewMenuItem(MenuId.DebugVariablesContext, SET_VARIABLE_ID, nls.localize('setValue', "Set Value"), 10, ContextKeyExpr.or(CONTEXT_SET_VARIABLE_SUPPORTED, ContextKeyExpr.and(CONTEXT_VARIABLE_EVALUATE_NAME_PRESENT, CONTEXT_SET_EXPRESSION_SUPPORTED)), CONTEXT_VARIABLE_IS_READONLY.toNegated(), '3_modification');
+registerDebugViewMenuItem(MenuId.DebugVariablesContext, VIEW_MEMORY_ID, nls.localize('viewMemory', "View Memory"), 15, CONTEXT_CAN_VIEW_MEMORY, CONTEXT_IN_DEBUG_MODE, '3_modification');
 registerDebugViewMenuItem(MenuId.DebugVariablesContext, COPY_VALUE_ID, nls.localize('copyValue', "Copy Value"), 10, undefined, undefined, '5_cutcopypaste');
 registerDebugViewMenuItem(MenuId.DebugVariablesContext, COPY_EVALUATE_PATH_ID, nls.localize('copyAsExpression', "Copy as Expression"), 20, CONTEXT_VARIABLE_EVALUATE_NAME_PRESENT, undefined, '5_cutcopypaste');
 registerDebugViewMenuItem(MenuId.DebugVariablesContext, ADD_TO_WATCH_ID, nls.localize('addToWatchExpressions', "Add to Watch"), 100, CONTEXT_VARIABLE_EVALUATE_NAME_PRESENT, undefined, 'z_commands');
@@ -154,6 +155,7 @@ registerDebugViewMenuItem(MenuId.DebugWatchContext, ADD_WATCH_ID, ADD_WATCH_LABE
 registerDebugViewMenuItem(MenuId.DebugWatchContext, EDIT_EXPRESSION_COMMAND_ID, nls.localize('editWatchExpression', "Edit Expression"), 20, CONTEXT_WATCH_ITEM_TYPE.isEqualTo('expression'), undefined, '3_modification');
 registerDebugViewMenuItem(MenuId.DebugWatchContext, SET_EXPRESSION_COMMAND_ID, nls.localize('setValue', "Set Value"), 30, ContextKeyExpr.or(ContextKeyExpr.and(CONTEXT_WATCH_ITEM_TYPE.isEqualTo('expression'), CONTEXT_SET_EXPRESSION_SUPPORTED), ContextKeyExpr.and(CONTEXT_WATCH_ITEM_TYPE.isEqualTo('variable'), CONTEXT_SET_VARIABLE_SUPPORTED)), CONTEXT_VARIABLE_IS_READONLY.toNegated(), '3_modification');
 registerDebugViewMenuItem(MenuId.DebugWatchContext, COPY_VALUE_ID, nls.localize('copyValue', "Copy Value"), 40, ContextKeyExpr.or(CONTEXT_WATCH_ITEM_TYPE.isEqualTo('expression'), CONTEXT_WATCH_ITEM_TYPE.isEqualTo('variable')), CONTEXT_IN_DEBUG_MODE, '3_modification');
+registerDebugViewMenuItem(MenuId.DebugWatchContext, VIEW_MEMORY_ID, nls.localize('viewMemory', "View Memory"), 50, CONTEXT_CAN_VIEW_MEMORY, CONTEXT_IN_DEBUG_MODE, '3_modification');
 registerDebugViewMenuItem(MenuId.DebugWatchContext, REMOVE_EXPRESSION_COMMAND_ID, nls.localize('removeWatchExpression', "Remove Expression"), 10, CONTEXT_WATCH_ITEM_TYPE.isEqualTo('expression'), undefined, 'z_commands');
 registerDebugViewMenuItem(MenuId.DebugWatchContext, REMOVE_WATCH_EXPRESSIONS_COMMAND_ID, REMOVE_WATCH_EXPRESSIONS_LABEL, 20, undefined, undefined, 'z_commands');