1 files changed, 102 insertions, 0 deletions
diff --git a/src/crypto/nodeEmscriptenLoader.ts b/src/crypto/nodeEmscriptenLoader.ts
new file mode 100644
index 000000000..6d6a7306b
--- /dev/null
+++ b/src/crypto/nodeEmscriptenLoader.ts
@@ -0,0 +1,102 @@
+
+import { EmscEnvironment } from "./emscInterface";
+import { CryptoImplementation } from "./cryptoImplementation";
+
+import fs = require("fs");
+
+export class NodeEmscriptenLoader {
+  private cachedEmscEnvironment: EmscEnvironment | undefined = undefined;
+  private cachedEmscEnvironmentPromise:
+    | Promise<EmscEnvironment>
+    | undefined = undefined;
+
+    private async getWasmBinary(): Promise<Uint8Array> {
+      // @ts-ignore
+      const akonoGetData = global.__akono_getData;
+      if (akonoGetData) {
+        // We're running embedded node on Android
+        console.log("reading wasm binary from akono");
+        const data = akonoGetData("taler-emscripten-lib.wasm");
+        // The data we get is base64-encoded binary data
+        let buf = new Buffer(data, 'base64');
+        return new Uint8Array(buf);
+  
+      } else {
+        // We're in a normal node environment
+        const binaryPath = __dirname + "/../../../emscripten/taler-emscripten-lib.wasm";
+        console.log("reading from", binaryPath);
+        const wasmBinary = new Uint8Array(fs.readFileSync(binaryPath));
+        return wasmBinary;
+      }
+    }
+  
+    async getEmscriptenEnvironment(): Promise<EmscEnvironment> {
+      if (this.cachedEmscEnvironment) {
+        return this.cachedEmscEnvironment;
+      }
+  
+      if (this.cachedEmscEnvironmentPromise) {
+        return this.cachedEmscEnvironmentPromise;
+      }
+  
+      let lib: any;
+  
+      const wasmBinary = await this.getWasmBinary();
+  
+      return new Promise((resolve, reject) => {
+        // Arguments passed to the emscripten prelude
+        const libArgs = {
+          wasmBinary,
+          onRuntimeInitialized: () => {
+            if (!lib) {
+              console.error("fatal emscripten initialization error");
+              return;
+            }
+            this.cachedEmscEnvironmentPromise = undefined;
+            this.cachedEmscEnvironment = new EmscEnvironment(lib);
+            resolve(this.cachedEmscEnvironment);
+          },
+        };
+  
+        // Make sure that TypeScript doesn't try
+        // to check the taler-emscripten-lib.
+        const indirectRequire = require;
+  
+        const g = global;
+  
+        // unavoidable hack, so that emscripten detects
+        // the environment as node even though importScripts
+        // is present.
+  
+        // @ts-ignore
+        const savedImportScripts = g.importScripts;
+        // @ts-ignore
+        delete g.importScripts;
+        // @ts-ignore
+        const savedCrypto = g.crypto;
+        // @ts-ignore
+        delete g.crypto;
+  
+        // Assume that the code is run from the build/ directory.
+        const libFn = indirectRequire(
+          "../../../emscripten/taler-emscripten-lib.js",
+        );
+        lib = libFn(libArgs);
+  
+        // @ts-ignore
+        g.importScripts = savedImportScripts;
+        // @ts-ignore
+        g.crypto = savedCrypto;
+  
+        if (!lib) {
+          throw Error("could not load taler-emscripten-lib.js");
+        }
+  
+        if (!lib.ccall) {
+          throw Error(
+            "sanity check failed: taler-emscripten lib does not have 'ccall'",
+          );
+        }
+      });
+    }
+}