1 files changed, 95 insertions, 0 deletions
diff --git a/src/exec_php.ts b/src/exec_php.ts
new file mode 100644
index 0000000..3c38cf4
--- /dev/null
+++ b/src/exec_php.ts
@@ -0,0 +1,95 @@
+import phpWasmBridgeUrl from "./php-wasm-bridge.js?url";
+
+export type PHPExecResult = {
+	success: boolean;
+	stdout: string;
+	stderr: string;
+};
+
+const BUFFER_MAX = 1024;
+
+let fetchingWasmBinaryPromise: Promise<ArrayBuffer> | null = null;
+
+// Fetching is performed only once.
+async function fetchWasmBinary(): Promise<ArrayBuffer> {
+	if (!fetchingWasmBinaryPromise) {
+		fetchingWasmBinaryPromise = new Promise((resolve, reject) => {
+			fetch("/php-wasm.wasm")
+				.then((res) => {
+					if (!res.ok) {
+						reject(`Failed to fetch wasm binary: ${res.status} (${res.url})`);
+					}
+					return res;
+				})
+				.then((res) => res.arrayBuffer())
+				.then((buf) => resolve(buf));
+		});
+	}
+	return fetchingWasmBinaryPromise;
+}
+
+export async function execPHP(code: string): Promise<PHPExecResult> {
+	let stdinPos = 0; // bytewise
+	const stdinBuf = new TextEncoder().encode(code);
+	let stdoutPos = 0; // bytewise
+	const stdoutBuf = new Uint8Array(BUFFER_MAX);
+	let stderrPos = 0; // bytewise
+	const stderrBuf = new Uint8Array(BUFFER_MAX);
+
+	const { default: PHPWasm } = await import(
+		/* @vite-ignore */ phpWasmBridgeUrl
+	);
+	const { ccall } = await PHPWasm({
+		wasmBinary: await fetchWasmBinary(),
+		stdin: () => {
+			if (stdinBuf.length <= stdinPos) {
+				return null;
+			}
+			return stdinBuf[stdinPos++];
+		},
+		stdout: (asciiCode: number | null) => {
+			if (asciiCode === null) {
+				return; // flush
+			}
+			if (BUFFER_MAX <= stdoutPos) {
+				return; // ignore
+			}
+			if (asciiCode < 0) {
+				asciiCode += 256;
+			}
+			stdoutBuf[stdoutPos++] = asciiCode;
+		},
+		stderr: (asciiCode: number | null) => {
+			if (asciiCode === null) {
+				return; // flush
+			}
+			if (BUFFER_MAX <= stderrPos) {
+				return; // ignore
+			}
+			if (asciiCode < 0) {
+				asciiCode += 256;
+			}
+			stderrBuf[stderrPos++] = asciiCode;
+		},
+	});
+
+	let result;
+	let extraError = null;
+	try {
+		result = ccall("php_wasm_run", "number", ["string"], [code]);
+	} catch (e) {
+		if (e instanceof WebAssembly.RuntimeError) {
+			extraError = e.message;
+		} else {
+			throw e;
+		}
+	}
+	const stdout = new TextDecoder().decode(stdoutBuf.subarray(0, stdoutPos));
+	const stderr = new TextDecoder().decode(stderrBuf.subarray(0, stderrPos));
+
+	return {
+		success: result === 0,
+		stdout,
+		stderr: extraError == null ? stderr : `${stderr}\n${extraError}`,
+	};
+}