JetCore/jetc/jetc.cpp

#include "JetParser.h"
#include "JetCodegen.h"
#include <fstream>
#include <sstream>
#include <iostream>
#include <cctype>
#include <vector>

namespace {

   std::string baseNameNoExt(const std::string &path) {
      size_t slash = path.find_last_of("/\\");
      std::string base = (slash == std::string::npos) ? path : path.substr(slash + 1);
      size_t dot = base.find_last_of('.');
      if (dot != std::string::npos) base = base.substr(0, dot);
      return base;
   }

   std::string sanitizeIdent(const std::string &s) {
      std::string r;
      for (char c : s) r += (std::isalnum((unsigned char)c) || c == '_') ? c : '_';
      return r;
   }

}

int main(int argc, char **argv) {
   bool shared = false;
   std::vector<std::string> pos;
   for (int i = 1; i < argc; ++i) {
      std::string a = argv[i];
      if (a == "--shared") shared = true;
      else pos.push_back(a);
   }
   if (pos.size() < 2) {
      std::cerr << "usage: jetc [--shared] <input.jet> <output.cpp>" << std::endl;
      std::cerr << "  --shared  emit a dlsym()-able entry point (see build-shared.sh)" << std::endl;
      std::cerr << "            instead of a standalone main()." << std::endl;
      return 1;
   }
   const std::string &inputPath = pos[0];
   const std::string &outputPath = pos[1];

   std::ifstream in(inputPath);
   if (!in) {
      std::cerr << "jetc: cannot open " << inputPath << std::endl;
      return 1;
   }
   std::ostringstream ss;
   ss << in.rdbuf();
   std::string src = ss.str();

   // Skip a leading shebang line, mirroring jet-2.0.cpp's own data.goeol()
   // call (run before it constructs the top-level __jet tag) so a
   // "#!../jet-2.0" first line doesn't get compiled in as literal output.
   if (src.rfind("#!", 0) == 0) {
      size_t nl = src.find('\n');
      src = (nl == std::string::npos) ? std::string() : src.substr(nl + 1);
   }

   // Consume zero or more leading "#api METHOD /path" directive lines
   // (right after the optional shebang), the same way the shebang itself
   // is stripped - a plain directive line, not a new tag/attribute concept,
   // since jetc's parser has no existing notion of the enclosing <jet> tag's
   // attributes to hang this off of. Each becomes one route this template
   // wants to serve once loaded as a .so (see JetCodegen's apiRoutes).
   std::vector<jetc::ApiRoute> apiRoutes;
   while (src.rfind("#api ", 0) == 0) {
      size_t nl = src.find('\n');
      std::string line = (nl == std::string::npos) ? src : src.substr(0, nl);
      src = (nl == std::string::npos) ? std::string() : src.substr(nl + 1);

      std::istringstream ls(line);
      std::string tag, method, path;
      ls >> tag >> method >> path;
      if (method.empty() || path.empty() || path[0] != '/') {
         std::cerr << "jetc: malformed #api directive (expected \"#api METHOD /path\"): "
                    << line << std::endl;
         return 1;
      }
      for (auto &c : method) c = (char)std::toupper((unsigned char)c);
      apiRoutes.push_back({method, path});
   }

   try {
      jetc::Parser parser(src);
      auto nodes = parser.parseNodes();
      jetc::Codegen codegen;
      // Both symbols are derived from the input filename (not the output
      // path) so they stay stable and predictable for whatever builds and
      // dlsym()'s the resulting .so - unique per template, so multiple
      // compiled templates' .so's can coexist in one process even under
      // dlopen(..., RTLD_GLOBAL) instead of requiring isolated handles.
      std::string baseIdent = sanitizeIdent(baseNameNoExt(inputPath));
      std::string symbol = "jetc_render_" + baseIdent;
      std::string apiSymbol = "jetc_api_" + baseIdent;
      if (!apiRoutes.empty() && !shared)
         std::cerr << "jetc: warning: #api directive(s) present but --shared not specified - "
                       "route metadata will not be emitted" << std::endl;
      std::string cpp = codegen.generate(nodes, std::string("compiled from ") + inputPath, shared,
                                          symbol, apiRoutes, apiSymbol);
      std::ofstream outFile(outputPath);
      outFile << cpp;
      outFile.close();
      if (shared) {
         std::cout << "jetc: wrote " << outputPath << " (entry symbol: " << symbol << ")";
         if (!apiRoutes.empty())
            std::cout << " (api symbol: " << apiSymbol << ", " << apiRoutes.size() << " route(s))";
         std::cout << std::endl;
      } else {
         std::cout << "jetc: wrote " << outputPath << std::endl;
      }
   } catch (std::exception &e) {
      std::cerr << "jetc: " << e.what() << std::endl;
      return 1;
   }
   return 0;
}