New async constructor design

hqtsm · Jan 20, 2025 · ad3d265 · ad3d265
1 parent 67f4911
commit ad3d265
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Showing 3 changed files with 63 additions and 47 deletions.
diff --git a/macho/macho.test.ts b/macho/macho.test.ts
@@ -26,24 +26,14 @@ for (const { kind, arch, file, archs } of fixtures) {
 		const [macho] = await fixtureMacho(kind, arch, [file]);
 		const blob = new Blob([macho]);
 		for (const [arc, info] of archs) {
-			const m = new MachO();
-
-			assertEquals(m.isOpen(), false, arc);
-			assertEquals(m.offset(), 0, arc);
-			assertEquals(m.length(), 0, arc);
-			assertEquals(m.signingExtent(), 0, arc);
-			assertEquals(m.isSuspicious(), false, arc);
-
 			const bin = thin(macho, ...CPU_ARCHITECTURES.get(arc)!);
 			const offset = bin.byteOffset;
 			const length = offset ? bin.byteLength : blob.size;
-			if (offset) {
+			const m = offset
 				// deno-lint-ignore no-await-in-loop
-				await m.open(blob, offset, length);
-			} else {
+				? await MachO.MachO(blob, offset, length)
 				// deno-lint-ignore no-await-in-loop
-				await m.open(blob);
-			}
+				: await MachO.MachO(blob);
 
 			assertEquals(m.isOpen(), true, arc);
 			assertEquals(m.offset(), offset, arc);
@@ -87,13 +77,11 @@ for (const { kind, arch, file, archs } of fixtures) {
 	});
 }
 
-Deno.test('open under', async () => {
-	const macho = new MachO();
-
+Deno.test('read under', async () => {
 	let mh = new MachHeader(new ArrayBuffer(MachHeader.BYTE_LENGTH - 1));
 
 	await assertRejects(
-		() => macho.open(new Blob([mh.buffer])),
+		() => MachO.MachO(new Blob([mh.buffer])),
 		RangeError,
 		'Invalid header',
 	);
@@ -102,7 +90,7 @@ Deno.test('open under', async () => {
 	mh.magic = MH_MAGIC_64;
 
 	await assertRejects(
-		() => macho.open(new Blob([mh.buffer])),
+		() => MachO.MachO(new Blob([mh.buffer])),
 		RangeError,
 		'Invalid header',
 	);
@@ -113,7 +101,7 @@ Deno.test('open under', async () => {
 	mh.sizeofcmds = 2;
 
 	await assertRejects(
-		() => macho.open(new Blob([mh.buffer])),
+		() => MachO.MachO(new Blob([mh.buffer])),
 		RangeError,
 		'Invalid commands',
 	);
@@ -136,20 +124,22 @@ Deno.test('validateStructure LC_SYMTAB', async () => {
 	cmd.stroff = MachHeader.BYTE_LENGTH + SymtabCommand.BYTE_LENGTH;
 	cmd.strsize = extra;
 
-	let macho = new MachO();
-	await macho.open(new Blob([buffer]));
-
-	assertEquals(macho.isSuspicious(), false);
-
-	macho = new MachO();
-	await macho.open(new Blob([buffer, new ArrayBuffer(1)]));
-
-	assertEquals(macho.isSuspicious(), true);
+	{
+		const macho = await MachO.MachO(new Blob([buffer]));
+		assertEquals(macho.isSuspicious(), false);
+	}
 
-	macho = new MachO();
-	await macho.open(new Blob([buffer.slice(0, buffer.byteLength - 1)]));
+	{
+		const macho = await MachO.MachO(new Blob([buffer, new ArrayBuffer(1)]));
+		assertEquals(macho.isSuspicious(), true);
+	}
 
-	assertEquals(macho.isSuspicious(), true);
+	{
+		const macho = await MachO.MachO(
+			new Blob([buffer.slice(0, buffer.byteLength - 1)]),
+		);
+		assertEquals(macho.isSuspicious(), true);
+	}
 });
 
 Deno.test('validateStructure bad command size', async () => {
@@ -175,10 +165,9 @@ Deno.test('validateStructure bad command size', async () => {
 		cmd.cmd = LC;
 		cmd.cmdsize = cmdsize;
 
-		const macho = new MachO();
 		// deno-lint-ignore no-await-in-loop
 		await assertRejects(
-			() => macho.open(new Blob([buffer])),
+			() => MachO.MachO(new Blob([buffer])),
 			RangeError,
 			'Invalid command size',
 			tag,

diff --git a/macho/macho.ts b/macho/macho.ts
@@ -40,13 +40,25 @@ export class MachO extends MachOBase {
 	private mSuspicious = false;
 
 	/**
-	 * Open binary.
+	 * Create uninitialized Mach-O instance.
+	 */
+	protected constructor() {
+		super();
+	}
+
+	/**
+	 * Initialize instance.
 	 *
 	 * @param reader Reader object.
 	 * @param offset Offset for subsection.
 	 * @param length Length of subsection, requires offset.
+	 * @returns This instance.
 	 */
-	public async open(reader: Reader, offset = 0, length = 0): Promise<void> {
+	protected async MachO(
+		reader: Reader,
+		offset = 0,
+		length = 0,
+	): Promise<MachO> {
 		offset = (+offset || 0) - (offset % 1 || 0);
 		length = (+length || 0) - (length % 1 || 0);
 		this.mReader = reader;
@@ -86,6 +98,7 @@ export class MachO extends MachOBase {
 		if (mLength) {
 			this.validateStructure();
 		}
+		return this;
 	}
 
 	/**
@@ -235,4 +248,20 @@ export class MachO extends MachOBase {
 	public isSuspicious(): boolean {
 		return this.mSuspicious;
 	}
+
+	/**
+	 * Create Mach-O binary over a reader.
+	 *
+	 * @param reader Reader object.
+	 * @param offset Offset for subsection.
+	 * @param length Length of subsection, requires offset.
+	 * @returns Mach-O binary.
+	 */
+	public static async MachO(
+		reader: Reader,
+		offset = 0,
+		length = 0,
+	): Promise<MachO> {
+		return await new MachO().MachO(reader, offset, length);
+	}
 }
diff --git a/macho/universal.ts b/macho/universal.ts
@@ -257,23 +257,17 @@ export class Universal {
 		if (typeof a === 'number') {
 			if (this.isUniversal()) {
 				const length = this.lengthOfSlice(a);
-				const macho = new MachO();
-				await macho.open(this.mReader!, a, length);
-				return this.make(macho);
+				return this.make(await MachO.MachO(this.mReader!, a, length));
 			}
 			if (a === this.mBase) {
-				const macho = new MachO();
-				await macho.open(this.mReader!);
-				return macho;
+				return MachO.MachO(this.mReader!);
 			}
 		} else {
 			if (this.isUniversal()) {
 				return this.findImage(a);
 			}
 			if (this.mThinArch!.matches(a)) {
-				const macho = new MachO();
-				await macho.open(this.mReader!, this.mBase, this.mLength);
-				return macho;
+				return MachO.MachO(this.mReader!, this.mBase, this.mLength);
 			}
 		}
 		throw new RangeError('Architecture not found');
@@ -448,9 +442,13 @@ export class Universal {
 	 */
 	private async findImage(target: Const<Architecture>): Promise<MachO> {
 		const arch = this.findArch(target);
-		const macho = new MachO();
-		await macho.open(this.mReader!, this.mBase + arch.offset, arch.size);
-		return this.make(macho);
+		return this.make(
+			await MachO.MachO(
+				this.mReader!,
+				this.mBase + arch.offset,
+				arch.size,
+			),
+		);
 	}
 
 	/**