s2wasm: add outfile

src/command-line.h

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2015 WebAssembly Community Group participants
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//
+// Command line helpers.
+//
+
+#include "wasm.h"
+
+namespace wasm {
+
+struct Options {
+  bool debug;
+  std::string infile;
+  std::string outfile;
+  Options() : debug(false) {}
+};
+
+bool optionIs(const char *arg, const char *LongOpt, const char *ShortOpt) {
+  return strcmp(arg, LongOpt) == 0 || strcmp(arg, ShortOpt) == 0;
+}
+
+// TODO(jfb) Make this configurable: callers should pass in option handlers.
+void processCommandLine(int argc, const char *argv[], Options *options) {
+  for (size_t i = 1; i != argc; ++i) {
+    if (optionIs(argv[i], "--help", "-h")) {
+      std::cerr << "s2wasm INFILE\n\n"
+                   "Link .s file into .wast\n\n"
+                   "Optional arguments:\n"
+                   "  -n, --help    Show this help message and exit\n"
+                   "  -d, --debug   Print debug information to stderr\n"
+                   "  -o, --output  Output file (stdout if not specified)\n"
+                << std::endl;
+      exit(EXIT_SUCCESS);
+    } else if (optionIs(argv[i], "--debug", "-d")) {
+      options->debug = true;
+    } else if (optionIs(argv[i], "--output", "-o")) {
+      if (i + 1 == argc) {
+        std::cerr << "No output file" << std::endl;
+        exit(EXIT_FAILURE);
+      }
+      if (options->outfile.size()) {
+        std::cerr << "Expected only one output file, got '" << options->outfile
+                  << "' and '" << argv[i] << "'" << std::endl;
+        exit(EXIT_FAILURE);
+      }
+      options->outfile = argv[++i];
+    } else {
+      if (options->infile.size()) {
+        std::cerr << "Expected only one input file, got '" << options->infile
+                  << "' and '" << argv[i] << "'" << std::endl;
+        exit(EXIT_FAILURE);
+      }
+      options->infile = argv[i];
+    }
+  }
+}
+
+}  // namespace wasm

src/s2wasm-main.cpp

@@ -18,46 +18,58 @@
 // wasm2asm console tool
 //
 
+#include "command-line.h"
 #include "s2wasm.h"
 
 using namespace cashew;
 using namespace wasm;
 
-namespace wasm {
-int debug = 0;
-}
+int main(int argc, const char *argv[]) {
+  Options options;
+  processCommandLine(argc, argv, &options);
+
+  std::string input;
+  {
+    if (options.debug) {
+      std::cerr << "Loading '" << options.infile << "'..." << std::endl;
+    }
+    std::ifstream infile(options.infile);
+    if (!infile.is_open()) {
+      std::cerr << "Failed opening '" << options.infile << "'" << std::endl;
+      exit(EXIT_FAILURE);
+    }
+    infile.seekg(0, std::ios::end);
+    size_t insize = infile.tellg();
+    input.resize(insize + 1);
+    infile.seekg(0);
+    infile.read(&input[0], insize);
+  }
+
+  std::streambuf *buffer;
+  std::ofstream outfile;
+  if (options.outfile.size()) {
+    if (options.debug) std::cerr << "Opening '" << options.outfile << std::endl;
+    outfile.open(options.outfile, std::ofstream::out | std::ofstream::trunc);
+    if (!outfile.is_open()) {
+      std::cerr << "Failed opening '" << options.outfile << "'" << std::endl;
+      exit(EXIT_FAILURE);
+    }
+    buffer = outfile.rdbuf();
+  } else {
+    buffer = std::cout.rdbuf();
+  }
+  std::ostream out(buffer);
 
-int main(int argc, char **argv) {
-  debug = getenv("S2WASM_DEBUG") ? getenv("S2WASM_DEBUG")[0] - '0' : 0;
-
-  char *infile = argv[1];
-
-  if (debug) std::cerr << "loading '" << infile << "'...\n";
-  FILE *f = fopen(argv[1], "r");
-  assert(f);
-  fseek(f, 0, SEEK_END);
-  int size = ftell(f);
-  char *input = new char[size+1];
-  rewind(f);
-  int num = fread(input, 1, size, f);
-  // On Windows, ftell() gives the byte position (\r\n counts as two bytes), but when
-  // reading, fread() returns the number of characters read (\r\n is read as one char \n, and counted as one),
-  // so return value of fread can be less than size reported by ftell, and that is normal.
-  assert((num > 0 || size == 0) && num <= size);
-  fclose(f);
-  input[num] = 0;
-
-  if (debug) std::cerr << "parsing and wasming...\n";
+  if (options.debug) std::cerr << "Parsing and wasming..." << std::endl;
   AllocatingModule wasm;
-  S2WasmBuilder s2wasm(wasm, input);
+  S2WasmBuilder s2wasm(wasm, input.c_str(), options.debug);
 
-  if (debug) std::cerr << "emscripten gluing...\n";
+  if (options.debug) std::cerr << "Emscripten gluing..." << std::endl;
   std::stringstream meta;
   s2wasm.emscriptenGlue(meta);
 
-  if (debug) std::cerr << "printing...\n";
-  std::cout << wasm;
-  std::cout << meta.str();
+  if (options.debug) std::cerr << "Printing..." << std::endl;
+  out << wasm << meta.str() << std::endl;
 
-  if (debug) std::cerr << "done.\n";
+  if (options.debug) std::cerr << "Done." << std::endl;
 }

src/s2wasm.h

@@ -24,8 +24,6 @@
 
 namespace wasm {
 
-extern int debug; // wasm::debug is set in main(), typically from an env var
-
 cashew::IString EMSCRIPTEN_ASM_CONST("emscripten_asm_const");
 
 //
@@ -35,15 +33,17 @@ cashew::IString EMSCRIPTEN_ASM_CONST("emscripten_asm_const");
 class S2WasmBuilder {
   AllocatingModule& wasm;
   MixedArena& allocator;
-  char *s;
+  const char *s;
+  bool debug;
 
 public:
-  S2WasmBuilder(AllocatingModule& wasm, char *input) : wasm(wasm), allocator(wasm.allocator) {
-    s = input;
-    scan();
-    s = input;
-    process();
-    fix();
+ S2WasmBuilder(AllocatingModule& wasm, const char* input, bool debug)
+     : wasm(wasm), allocator(wasm.allocator), debug(debug) {
+   s = input;
+   scan();
+   s = input;
+   process();
+   fix();
   }
 
 private:
@@ -217,7 +217,7 @@ class S2WasmBuilder {
     skipWhitespace();
     if (*s != '$') return Name();
     std::string str;
-    char *before = s;
+    const char *before = s;
     while (*s && *s != '=' && *s != '\n' && *s != ',') {
       str += *s;
       s++;
@@ -393,7 +393,7 @@ class S2WasmBuilder {
     };
     auto getNumInputs = [&]() {
       int ret = 1;
-      char *t = s;
+      const char *t = s;
       while (*t != '\n') {
         if (*t == ',') ret++;
         t++;

src/wasm.h

@@ -47,6 +47,8 @@
 #include <cassert>
 #include <cstddef>
 #include <cstdint>
+#include <cstring>
+#include <fstream>
 #include <map>
 #include <vector>