MessageStore.cpp

   1 #include "MessageStore.hpp"
   2
   3 #include "osutil.hpp"
   4
   5 #include <cstdlib>
   6
   7 #include <fmt/format.h>
   8 #include <fmt/ostream.h>
   9
  10 namespace {
  11 auto locate_maildir() -> fs::path
  12 {
  13   auto const maildir_ev{getenv("MAILDIR")};
  14   if (maildir_ev) {
  15     return maildir_ev;
  16   }
  17   else {
  18     return osutil::get_home_dir() / "Maildir";
  19   }
  20 }
  21 } // namespace
  22
  23 void MessageStore::open(std::string_view fqdn,
  24                         std::streamsize  max_size,
  25                         std::string_view folder)
  26 {
  27   auto maildir = locate_maildir();
  28
  29   if (!folder.empty()) {
  30     maildir /= folder;
  31   }
  32
  33   newfn_  = maildir / "new";
  34   tmpfn_  = maildir / "tmp";
  35   tmp2fn_ = maildir / "tmp";
  36
  37   error_code ec;
  38   create_directories(newfn_, ec);
  39   create_directories(tmpfn_, ec);
  40
  41   // Unique name, see: <https://cr.yp.to/proto/maildir.html>
  42   auto const uniq{
  43       fmt::format("{}.R{}.{}", then_.sec(), s_.as_string_view(), fqdn)};
  44   newfn_ /= uniq;
  45   tmpfn_ /= uniq;
  46
  47   auto const uniq2{
  48       fmt::format("{}.R{}2.{}", then_.sec(), s_.as_string_view(), fqdn)};
  49   tmp2fn_ /= uniq2;
  50
  51   // open
  52   ofs_.exceptions(std::ifstream::failbit | std::ifstream::badbit);
  53   ofs_.open(tmpfn_);
  54
  55   max_size_ = max_size;
  56   size_     = 0;
  57 }
  58
  59 std::ostream& MessageStore::write(char const* s, std::streamsize count)
  60 {
  61   if (!size_error_ && (size_ + count) <= max_size_) {
  62     size_ += count;
  63     return ofs_.write(s, count);
  64   }
  65   else {
  66     size_error_ = true;
  67     return ofs_;
  68   }
  69 }
  70
  71 void MessageStore::try_close_()
  72 {
  73   try {
  74     if (ofs_.is_open())
  75       ofs_.close();
  76   }
  77   catch (std::system_error const& e) {
  78     LOG(ERROR) << e.what() << "code: " << e.code();
  79   }
  80   catch (std::exception const& e) {
  81     LOG(ERROR) << e.what();
  82   }
  83 }
  84
  85 std::string_view MessageStore::freeze()
  86 {
  87   try_close_();
  88   error_code ec;
  89   if (fs::exists(tmp2fn_)) {
  90     fs::remove(tmp2fn_, ec);
  91     if (ec) {
  92       LOG(WARNING) << "problem removing " << tmp2fn_ << ": " << ec;
  93     }
  94   }
  95   rename(tmpfn_, tmp2fn_, ec);
  96   if (ec) {
  97     LOG(ERROR) << "can't rename " << tmpfn_ << " to " << tmp2fn_ << ": " << ec;
  98   }
  99   ofs_.open(tmpfn_);
 100   mapping_.open(tmp2fn_);
 101   size_ = 0;
 102   return std::string_view(mapping_.data(), mapping_.size());
 103 }
 104
 105 void MessageStore::deliver()
 106 {
 107   if (size_error()) {
 108     LOG(WARNING) << "message size error: " << size() << " exceeds "
 109                  << max_size();
 110   }
 111
 112   try_close_();
 113
 114   error_code ec;
 115   rename(tmpfn_, newfn_, ec);
 116   if (ec) {
 117     LOG(ERROR) << "can't rename " << tmpfn_ << " to " << newfn_ << ": " << ec;
 118   }
 119
 120   if (fs::exists(newfn_)) {
 121     LOG(INFO) << "successfully deliverd " << newfn_;
 122   }
 123   else {
 124     LOG(ERROR) << "failed to deliver " << newfn_;
 125   }
 126 }
 127
 128 void MessageStore::close()
 129 {
 130   try_close_();
 131
 132   error_code ec;
 133   fs::remove(tmpfn_, ec);
 134   if (ec) {
 135     LOG(ERROR) << "can't remove " << tmpfn_ << ": " << ec;
 136   }
 137   if (fs::exists(tmp2fn_)) {
 138     fs::remove(tmp2fn_, ec);
 139     if (ec) {
 140       LOG(ERROR) << "can't remove " << tmp2fn_ << ": " << ec;
 141     }
 142   }
 143   if (mapping_.is_open()) {
 144     mapping_.close();
 145   }
 146 }