From a77417d73c423dfb0bb0fc9e6d568f1429ed1723 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E2=80=9CPaulo?= <paulo@ubook.com>
Date: Fri, 13 Sep 2024 03:38:46 -0300
Subject: [PATCH] add support for wasm standalone

---
 .github/workflows/wasm.yml |  3 ++
 make.py                    |  5 +++
 modules/wasm.py            | 84 ++++++++++++++++++++++++++++++++++++--
 requirements.txt           |  1 +
 4 files changed, 89 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/wasm.yml b/.github/workflows/wasm.yml
index f3883d4..ce3e146 100644
--- a/.github/workflows/wasm.yml
+++ b/.github/workflows/wasm.yml
@@ -90,6 +90,9 @@ jobs:
       - name: Test
         run: python3 make.py test-${{ matrix.config.target }}
 
+      - name: Test WasmTime
+        run: python3 make.py test-${{ matrix.config.target }}time
+
       - name: Generate
         run: python3 make.py generate-${{ matrix.config.target }}
 
diff --git a/make.py b/make.py
index fde4ff1..3771295 100755
--- a/make.py
+++ b/make.py
@@ -49,6 +49,7 @@
   - build-wasm
   - install-wasm
   - test-wasm
+  - test-wasmtime
   - generate-wasm
   - publish-wasm
   - publish-to-web-wasm
@@ -211,6 +212,10 @@ def main(options):
     elif task == "test-wasm":
         wasm.run_task_test()
 
+    # test - wasmtime
+    elif task == "test-wasmtime":
+        wasm.run_task_test_wasmtime()
+
     # generate - wasm
     elif task == "generate-wasm":
         wasm.run_task_generate()
diff --git a/modules/wasm.py b/modules/wasm.py
index 126b9a3..80c0afb 100644
--- a/modules/wasm.py
+++ b/modules/wasm.py
@@ -523,6 +523,70 @@ def run_task_test():
     l.ok()
 
 
+# -----------------------------------------------------------------------------
+def run_task_test_wasmtime():
+    import wasmtime
+    from wasmtime import Engine, Func, Instance, Linker, Module, Store
+    from wasmtime.loader import WasiConfig
+
+    l.colored("Testing with wasmtime...", l.YELLOW)
+
+    current_dir = f.current_dir()
+
+    for target in c.targets_wasm:
+        # paths
+        relative_dir = os.path.join(
+            "build",
+            target["target_os"],
+            target["target_cpu"],
+        )
+
+        root_dir = os.path.join(current_dir, relative_dir)
+        gen_dir = os.path.join(root_dir, "gen")
+        gen_out_dir = os.path.join(gen_dir, "out")
+        wasm_file = os.path.join(gen_out_dir, "pdfium.std.wasm")
+
+        # create the engine and store
+        engine = Engine()
+        store = Store(engine)
+
+        # load the WebAssembly module
+        module = Module.from_file(engine, wasm_file)
+
+        # create a linker to provide the necessary imports
+        linker = Linker(engine)
+
+        # WASI support using wasmtime.loader.WasiConfig
+        wasi_config = WasiConfig()
+        wasi_config.inherit_stdin()
+        wasi_config.inherit_stdout()
+        wasi_config.inherit_stderr()
+        store.set_wasi(wasi_config)
+
+        # instantiate the WebAssembly module with linker
+        instance = linker.instantiate(store, module)
+
+        # now we can invoke exported functions from the WebAssembly module
+        try:
+            init_library = instance.exports(store)["FPDF_InitLibrary"]
+            init_library(store)
+            l.i("FPDF_InitLibrary successfully called.")
+        except KeyError:
+            l.e("Function 'FPDF_InitLibrary' not found.")
+
+        # invoke 'FPDF_GetLastError'
+        try:
+            get_last_error = instance.exports(store)["FPDF_GetLastError"]
+            result = get_last_error(store)
+            l.i(f"Result from FPDF_GetLastError: {result}")
+        except KeyError:
+            l.e("Function 'FPDF_GetLastError' not found.")
+
+        l.i(f"Result: {result}")
+
+    l.ok()
+
+
 # -----------------------------------------------------------------------------
 def run_task_generate():
     l.colored("Generating...", l.YELLOW)
@@ -660,21 +724,33 @@ def run_task_generate():
                 *base_command,
                 "-o",
                 os.path.join(gen_out_dir, "pdfium.js"),
- 
             ]
             r.run(" ".join(umd_command), cwd=gen_utils_dir, shell=True)
-            
+
             # Generate ES6 module, only .js will be generated (no .wasm)
             l.colored("Compiling ES6 module with emscripten...", l.YELLOW)
             es6_command = [
                 *base_command,
-                "-s"
-                "EXPORT_ES6=1",
+                "-s" "EXPORT_ES6=1",
                 "-o",
                 os.path.join(gen_out_dir, "pdfium.esm.js"),
             ]
             r.run(" ".join(es6_command), cwd=gen_utils_dir, shell=True)
 
+            # Generate STANDALONE module, only .js will be generated (no .wasm)
+            l.colored("Compiling STANDALONE module with emscripten...", l.YELLOW)
+            std_command = [
+                *base_command,
+                "-s" "STANDALONE_WASM=1",
+                "-sSTANDALONE_WASM=1",
+                "-sWASM_ASYNC_COMPILATION=0",
+                "-sWARN_ON_UNDEFINED_SYMBOLS=1",
+                "-sERROR_ON_UNDEFINED_SYMBOLS=0",
+                "-o",
+                os.path.join(gen_out_dir, "pdfium.std.js"),
+            ]
+            r.run(" ".join(std_command), cwd=gen_utils_dir, shell=True)
+
             # copy files
             l.colored("Copying compiled files...", l.YELLOW)
 
diff --git a/requirements.txt b/requirements.txt
index 1b8aa83..475b37c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,4 @@
 docopt
 black
 pygemstones>=0.0.13
+wasmtime