JetCore/__include.cpp

#include "__include.h"
#include "Exception.h"
#include "File.h"
#include <string>
#include <unordered_map>
#include <sys/stat.h>

namespace jet {

   namespace {
      struct CachedInclude {
	 std::string content;
	 time_t mtime;
      };
      // Persistent, per-worker-thread cache of <include> file contents,
      // keyed by resolved filename. Real content depends on this
      // constantly through custom tag bodies that jetc's own compile-
      // time <include>-inlining doesn't reach (only the top-level .jet
      // source's own includes get compiled in) - mainpagetemplate.temp
      // alone pulls in login.menu/menu.bar/opensource.menu/cart.menu/
      // sessionvar.menu, all previously re-read from disk on every
      // single request even though the files are 100% static between
      // edits. Invalidated via mtime comparison (a stat() call, cheap
      // relative to a full read()) so a live edit still takes effect on
      // the very next request - matching the workflow already relied on
      // all session of editing .tag/.temp/.menu content directly and
      // seeing it live without a rebuild.
      thread_local std::unordered_map<std::string, CachedInclude> includeCache;
   }

   __include::__include(coreutils::ZString &in, coreutils::MString &parentOut, Global &global, Tag *parent, Tag *local) : Tag(in, parentOut, global, parent, local) {
      if(!keywordDefined("file"))
	throw coreutils::Exception("file keyword must be specified.");
      if(hasContainer)
	throw coreutils::Exception("include tag should not have a container.");
      hasContainer = true;
      coreutils::MString includeFileName = resolveKeyword("file");
      std::string fileNameKey = includeFileName.str();

      struct stat st;
      bool haveStat = (stat(fileNameKey.c_str(), &st) == 0);

      auto cached = includeCache.find(fileNameKey);
      if(cached != includeCache.end() && haveStat && cached->second.mtime == st.st_mtime) {
	 container = coreutils::ZString(cached->second.content.data(), cached->second.content.length());
      } else {
	 coreutils::File file(includeFileName);
	 file.read();
	 if(haveStat) {
	    CachedInclude &entry = includeCache[fileNameKey];
	    entry.content = file.asString();
	    entry.mtime = st.st_mtime;
	    container = coreutils::ZString(entry.content.data(), entry.content.length());
	 } else {
	    // Couldn't stat the file (unusual - e.g. a race with deletion) -
	    // don't cache something we can't validate the freshness of,
	    // just render this one read directly, matching the pre-cache
	    // behavior exactly for this edge case.
	    container = file.asZString();
	 }
      }

      try {
	 processContainer(container);
      }
      catch(coreutils::Exception e) {
	 // global.errorCursor is whatever cursor was active in whichever
	 // ZString buffer was being parsed at the moment the ORIGINAL
	 // exception was thrown - not necessarily this include's own
	 // `container` buffer at all (e.g. a keyword-resolution error
	 // happening while interpreting a completely different .temp
	 // file's own text). setCursor() on a pointer outside container's
	 // own [data, data+length] range throws "Cursor out of range on
	 // setCursor." - and since that happens INSIDE this diagnostic-
	 // only "show a nice line number" block, it was replacing the
	 // real error (e.text) with that unrelated cursor-range message
	 // before it ever reached the caller, making every real error
	 // from inside an <include> impossible to see. This is purely
	 // diagnostic output - if it can't compute a line number, fall
	 // back to printing the real error text without one rather than
	 // losing it entirely.
	 try {
	    container.setCursor(global.errorCursor);
	    container.moveBackToLineStart();
	    std::cout << "-----------------------------" << std::endl;
	    std::cout << "Error in included script '" << variables["file"] << "' at line " << container.getLineNumberAtCursor() << std::endl;
	    std::cout << "Error text: " << e.text << std::endl;
	    std::cout << "-----------------------------" << std::endl;
	    std::cout << container.parsed() << std::endl;
	    std::cout << "******** Error caught: " << e.text << std::endl;
	    std::cout << container.unparsed() << std::endl;
	 } catch(coreutils::Exception &) {
	    std::cout << "-----------------------------" << std::endl;
	    std::cout << "Error in included script '" << variables["file"] << "' (line number unavailable - error originated outside this include's own content)" << std::endl;
	    std::cout << "Error text: " << e.text << std::endl;
	    std::cout << "-----------------------------" << std::endl;
	 }
	 global.errorCursor = in.getCursor();
	 throw coreutils::Exception(e.text);
      }

   }

}