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, 9 insertions, 14 deletions

diff --git a/src/uline.cc b/src/uline.cc
index 7d4c7c7..358f36c 100644
--- a/src/uline.cc
+++ b/src/uline.cc
@@ -30,7 +30,7 @@ class UnicodeReader {
         end_(buffer_.get() + check::add(max_len, static_cast<size_t>(2))) {}
 
   [[nodiscard]]
-  std::expected<std::basic_string_view<T>, line::ReadError> read() {
+  std::expected<std::basic_string_view<T>, io::ReadError> read() {
     while (true) {
       search_ = std::find_first_of(search_, wptr_, line_terminators_.begin(),
                                    line_terminators_.end());
@@ -46,12 +46,11 @@ class UnicodeReader {
           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(line::ReadError(got.error()));
+              return std::unexpected(got.error());
             }
           }
           if (search_[1] == line_terminators_[1]) {
@@ -68,15 +67,11 @@ class UnicodeReader {
 
       make_space_if_needed();
       auto got = fill();
-      if (got.has_value()) {
-        if (got.value() == 0) {
-          if (rptr_ == wptr_) {
-            return std::unexpected(line::ReadError());
-          }
+      if (!got.has_value()) {
+        if (got.error() == io::ReadError::Eof && rptr_ != wptr_) {
           return line(wptr_ - rptr_, 0);
         }
-      } else {
-        return std::unexpected(line::ReadError(got.error()));
+        return std::unexpected(got.error());
       }
     }
   }
@@ -138,7 +133,7 @@ class ReaderImpl : public UnicodeReader<char, u8::Reader>,
                                         {'\r', '\n'}) {}
 
   [[nodiscard]]
-  std::expected<std::string_view, ::line::ReadError> read() override {
+  std::expected<std::string_view, io::ReadError> read() override {
     return UnicodeReader<char, u8::Reader>::read();
   }
 
@@ -170,7 +165,7 @@ class ReaderImpl : public UnicodeReader<char16_t, u16::Reader>,
                                              {u'\r', u'\n'}) {}
 
   [[nodiscard]]
-  std::expected<std::u16string_view, ::line::ReadError> read() override {
+  std::expected<std::u16string_view, io::ReadError> read() override {
     return UnicodeReader<char16_t, u16::Reader>::read();
   }