Windows: Implementing C++ DEF parser

C++ DEF parser can generating a DEF file from a object file, which can
be used to export symbols during linking DLL on Windows.

This parser is based on an implementation in CMake
See https://github.com/Kitware/CMake/blob/master/Source/bindexplib.cxx
A few changes has been made to make it work better.

Usage: output_deffile dllname [objfile ...] [input_deffile ...] [@paramfile ...]

output_deffile: the output DEF file

dllname: the DLL name this DEF file is used for, if dllname is not empty
         string (eg. ""), def_parser writes an 'LIBRARY <dllname>' entry
         into DEF file.

objfile: a object file, def_parser parses this file to find symbols,
         then merges them into final result.
         Can apppear multiple times.

input_deffile: an existing def file, def_parser merges all symbols in this file.
               Can appear multiple times.

@paramfile: a parameter file that can contain objfile and input_deffile
            Can appear multiple time.

Change-Id: I0ee65fa3119ecae2ea195b707af5690e4bc6a6c2

1 files changed, 77 insertions, 0 deletions

diff --git a/third_party/def_parser/def_parser_main.cc b/third_party/def_parser/def_parser_main.cc
new file mode 100644
index 0000000000..a92f0e9aa0
--- /dev/null
+++ b/third_party/def_parser/def_parser_main.cc
@@ -0,0 +1,77 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+
+#include <fstream>
+#include <iostream>
+#include <string>
+
+#include "third_party/def_parser/def_parser.h"
+
+static const char* ws = " \t\n\r\f\v";
+
+inline void trim(std::string *str) {
+  // Remove prefixing spaces
+  str->erase(0, str->find_first_not_of(ws));
+  // Remove suffixing spaces
+  str->erase(str->find_last_not_of(ws) + 1);
+}
+
+int main(int argc, char* argv[]) {
+  if (argc < 4) {
+    std::cerr << "Usage: output_def_file dllname [objfile ...] [input_deffile ...] [@paramfile ...]\n";
+    std::cerr << "output_deffile: the output DEF file\n";
+    std::cerr << "\n";
+    std::cerr << "dllname: the DLL name this DEF file is used for, if dllname is not empty\n";
+    std::cerr << "         string (eg. ""), def_parser writes an 'LIBRARY <dllname>' entry\n";
+    std::cerr << "         into DEF file.\n";
+    std::cerr << "\n";
+    std::cerr << "objfile: a object file, def_parser parses this file to find symbols,\n";
+    std::cerr << "         then merges them into final result.\n";
+    std::cerr << "         Can apppear multiple times.\n";
+    std::cerr << "\n";
+    std::cerr << "input_deffile: an existing def file, def_parser merges all symbols in this file.\n";
+    std::cerr << "               Can appear multiple times.\n";
+    std::cerr << "\n";
+    std::cerr << "@paramfile: a parameter file that can contain objfile and input_deffile.\n";
+    std::cerr << "            Can appear multiple time.\n";
+    return 1;
+  }
+
+  FILE* fout = fopen(argv[1], "w+");
+  if (!fout) {
+    std::cerr << "Could not open output .def file: " << argv[1] << "\n";
+    return 1;
+  }
+
+  DefParser deffile;
+
+  deffile.SetDLLName(argv[2]);
+
+  for (int i = 3; i < argc; i++) {
+    // If the argument starts with @, then treat it as a parameter file.
+    if (argv[i][0] == '@') {
+      std::ifstream paramfile(argv[i] + 1, std::ios::in | std::ios::binary);
+      if (!paramfile) {
+        std::cerr << "Could not open parameter file: " << argv[i] << "\n";
+        return 1;
+      }
+      std::string file;
+      while (std::getline(paramfile, file)) {
+        trim(&file);
+        if (!deffile.AddFile(file)) {
+          return 1;
+        }
+      }
+    } else {
+      std::string file(argv[i]);
+      trim(&file);
+      if (!deffile.AddFile(argv[i])) {
+        return 1;
+      }
+    }
+  }
+
+  deffile.WriteFile(fout);
+  fclose(fout);
+  return 0;
+}