Change io::Reader and company to return ReadError::Eof instead of 0.

It's debatable if Eof should be considered an error or not.
But it is pretty clear it generally is a special response that
needs special handling, so easier to keep with the unexpected lot.

Also keeps better at higher abstraction levels, such as the line
reader.

1 files changed, 7 insertions, 16 deletions

diff --git a/src/line.cc b/src/line.cc
index 8ee7134..23370fc 100644
--- a/src/line.cc
+++ b/src/line.cc
@@ -29,7 +29,7 @@ class ReaderImpl : public Reader {
         search_(rptr_),
         end_(buffer_.get() + check::add(max_len, static_cast<size_t>(2))) {}
 
-  [[nodiscard]] std::expected<std::string_view, ReadError> read() override {
+  [[nodiscard]] std::expected<std::string_view, io::ReadError> read() override {
     while (true) {
       search_ = std::find_first_of(search_, wptr_, kLineTerminators,
                                    kLineTerminators + 2);
@@ -45,12 +45,11 @@ class ReaderImpl : public Reader {
           if (search_ + 1 == wptr_) {
             make_space_if_needed();
             auto got = fill();
-            if (got.has_value()) {
-              if (got.value() == 0) {
+            if (!got.has_value()) {
+              if (got.error() == io::ReadError::Eof) {
                 return line(search_ - rptr_, 1);
               }
-            } else {
-              return std::unexpected(ReadError(got.error()));
+              return std::unexpected(got.error());
             }
           }
           if (search_[1] == '\n') {
@@ -67,15 +66,11 @@ class ReaderImpl : public Reader {
 
       make_space_if_needed();
       auto got = fill();
-      if (got.has_value()) {
-        if (got.value() == 0) {
-          if (rptr_ == wptr_) {
-            return std::unexpected(ReadError());
-          }
+      if (!got.has_value()) {
+        if (got.error() == io::ReadError::Eof && rptr_ != wptr_) {
           return line(wptr_ - rptr_, 0);
         }
-      } else {
-        return std::unexpected(ReadError(got.error()));
+        return std::unexpected(got.error());
       }
     }
   }
@@ -124,10 +119,6 @@ class ReaderImpl : public Reader {
 
 }  // namespace
 
-ReadError::ReadError() : eof(true) {}
-
-ReadError::ReadError(io::ReadError error) : eof(false), io_error(error) {}
-
 std::unique_ptr<Reader> open(std::unique_ptr<io::Reader> reader,
                              size_t max_len) {
   return std::make_unique<ReaderImpl>(std::move(reader), max_len);