Renamed wasmer_wasm.h to wasmer.h

lib/c-api/examples/wasi.c

@@ -0,0 +1,172 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <inttypes.h>
+
+#include "wasmer.h"
+
+#define BUF_SIZE 128
+#define own
+
+// Use the last_error API to retrieve error messages
+void print_wasmer_error()
+{
+    int error_len = wasmer_last_error_length();
+    printf("Error len: `%d`\n", error_len);
+    char *error_str = malloc(error_len);
+    wasmer_last_error_message(error_str, error_len);
+    printf("Error str: `%s`\n", error_str);
+}
+
+int main(int argc, const char* argv[]) {
+  // Initialize.
+  printf("Initializing...\n");
+  wasm_engine_t* engine = wasm_engine_new();
+  wasm_store_t* store = wasm_store_new(engine);
+
+  // Load binary.
+  printf("Loading binary...\n");
+  FILE* file = fopen("assets/qjs.wasm", "r");
+  if (!file) {
+    printf("> Error loading module!\n");
+    return 1;
+  }
+  fseek(file, 0L, SEEK_END);
+  size_t file_size = ftell(file);
+  fseek(file, 0L, SEEK_SET);
+  wasm_byte_vec_t binary;
+  wasm_byte_vec_new_uninitialized(&binary, file_size);
+  if (fread(binary.data, file_size, 1, file) != 1) {
+    printf("> Error loading module!\n");
+    return 1;
+  }
+  fclose(file);
+
+  // Compile.
+  printf("Compiling module...\n");
+  own wasm_module_t* module = wasm_module_new(store, &binary);
+  if (!module) {
+    printf("> Error compiling module!\n");
+    return 1;
+  }
+
+  wasm_byte_vec_delete(&binary);
+
+  printf("Setting up WASI...\n");
+  wasi_config_t* config = wasi_config_new("example_program");
+  // TODO: error checking
+  const char* js_string = "function greet(name) { return JSON.stringify('Hello, ' + name); }; print(greet('World'));";
+  wasi_config_arg(config, "--eval");
+  wasi_config_arg(config, js_string);
+  wasi_config_capture_stdout(config);
+
+  wasi_env_t* wasi_env = wasi_env_new(config);
+  if (!wasi_env) {
+    printf("> Error building WASI env!\n");
+    print_wasmer_error();
+    return 1;
+  }
+
+  // Instantiate.
+  printf("Instantiating module...\n");
+  wasm_importtype_vec_t import_types;
+  wasm_module_imports(module, &import_types);
+
+  wasm_extern_vec_t imports;
+  wasm_extern_vec_new_uninitialized(&imports, import_types.size);
+  wasm_importtype_vec_delete(&import_types);
+
+  bool get_imports_result = wasi_get_imports(store, module, wasi_env, &imports);
+
+  if (!get_imports_result) {
+    printf("> Error getting WASI imports!\n");
+    print_wasmer_error();
+    return 1;
+  }
+
+  own wasm_instance_t* instance =
+    wasm_instance_new(store, module, &imports, NULL);
+
+  if (!instance) {
+    printf("> Error instantiating module!\n");
+    print_wasmer_error();
+    return 1;
+  }
+
+
+  // Extract export.
+  printf("Extracting export...\n");
+  own wasm_extern_vec_t exports;
+  wasm_instance_exports(instance, &exports);
+  if (exports.size == 0) {
+    printf("> Error accessing exports!\n");
+    return 1;
+  }
+  fprintf(stderr, "found %zu exports\n", exports.size);
+
+  wasm_func_t* run_func = wasi_get_start_function(instance);
+  if (run_func == NULL) {
+    printf("> Error accessing export!\n");
+    print_wasmer_error();
+    return 1;
+  }
+
+  wasm_module_delete(module);
+  wasm_instance_delete(instance);
+
+  // Call.
+  printf("Calling export...\n");
+  printf("Evaluating \"%s\"\n", js_string);
+
+  wasm_val_vec_t args = WASM_EMPTY_VEC;
+  wasm_val_vec_t res = WASM_EMPTY_VEC;
+
+  if (wasm_func_call(run_func, &args, &res)) {
+    printf("> Error calling function!\n");
+    return 1;
+  }
+
+  {
+    FILE *memory_stream;
+    char* stdout;
+    size_t stdout_size = 0;
+
+    memory_stream = open_memstream(&stdout, &stdout_size);
+
+    if (NULL == memory_stream) {
+      printf("> Error creating a memory stream.\n");
+      return 1;
+    }
+
+    char buffer[BUF_SIZE] = { 0 };
+    size_t data_read_size = BUF_SIZE;
+
+    do {
+      data_read_size = wasi_env_read_stdout(wasi_env, buffer, BUF_SIZE);
+
+      if (data_read_size > 0) {
+        stdout_size += data_read_size;
+        fwrite(buffer, sizeof(char), data_read_size, memory_stream);
+      }
+    } while (BUF_SIZE == data_read_size);
+
+    fclose(memory_stream);
+
+    printf("WASI Stdout: `%.*s`\n", (int) stdout_size, stdout);
+  }
+
+
+  wasm_extern_vec_delete(&exports);
+  wasm_extern_vec_delete(&imports);
+
+  // Shut down.
+  printf("Shutting down...\n");
+  wasm_func_delete(run_func);
+  wasi_env_delete(wasi_env);
+  wasm_store_delete(store);
+  wasm_engine_delete(engine);
+
+  // All done.
+  printf("Done.\n");
+  return 0;
+}