1 files changed, 126 insertions, 11 deletions

diff --git a/src/common/io/Stream.cpp b/src/common/io/Stream.cpp
index 97cfcf99..6b0a513c 100644
--- a/src/common/io/Stream.cpp
+++ b/src/common/io/Stream.cpp
@@ -30,22 +30,73 @@ void StreamAlreadyClosedException::Check(bool closed) {
   if (closed) throw StreamAlreadyClosedException();
 }
 
-Index Stream::Tell() { return Seek(0, SeekOrigin::Current); }
+Stream::Stream(SupportedOperations supported_operations)
+    : supported_operations_(std::move(supported_operations)), closed_(false) {}
 
-void Stream::Rewind() { Seek(0, SeekOrigin::Begin); }
+Stream::Stream(std::optional<bool> can_seek, std::optional<bool> can_read,
+               std::optional<bool> can_write)
+    : Stream(SupportedOperations{can_seek, can_read, can_write}) {}
+
+bool Stream::CanSeek() {
+  CheckClosed();
+  return DoCanSeek();
+}
+
+Index Stream::Seek(Index offset, SeekOrigin origin) {
+  CheckClosed();
+  StreamOperationNotSupportedException::CheckSeek(DoCanSeek());
+  return DoSeek(offset, origin);
+}
+
+Index Stream::Tell() {
+  CheckClosed();
+  return DoTell();
+}
+
+void Stream::Rewind() {
+  CheckClosed();
+  return DoRewind();
+}
 
 Index Stream::GetSize() {
-  Index current_position = Tell();
-  Seek(0, SeekOrigin::End);
-  Index size = Tell();
-  Seek(current_position, SeekOrigin::Begin);
-  return size;
+  CheckClosed();
+  return DoGetSize();
+}
+
+bool Stream::CanRead() {
+  CheckClosed();
+  return DoCanRead();
+}
+
+Index Stream::Read(std::byte* buffer, Index offset, Index size) {
+  CheckClosed();
+  StreamOperationNotSupportedException::CheckRead(DoCanRead());
+  return DoRead(buffer, offset, size);
 }
 
 Index Stream::Read(std::byte* buffer, Index size) {
   return Read(buffer, 0, size);
 }
 
+Index Stream::Read(char* buffer, Index offset, Index size) {
+  return Read(reinterpret_cast<std::byte*>(buffer), offset, size);
+}
+
+Index Stream::Read(char* buffer, Index size) {
+  return Read(reinterpret_cast<std::byte*>(buffer), 0, size);
+}
+
+bool Stream::CanWrite() {
+  CheckClosed();
+  return DoCanWrite();
+}
+
+Index Stream::Write(const std::byte* buffer, Index offset, Index size) {
+  CheckClosed();
+  StreamOperationNotSupportedException::CheckWrite(DoCanWrite());
+  return DoWrite(buffer, offset, size);
+}
+
 Index Stream::Write(const std::byte* buffer, Index size) {
   return Write(buffer, 0, size);
 }
@@ -58,6 +109,74 @@ Index Stream::Write(const char* buffer, Index size) {
   return Write(reinterpret_cast<const std::byte*>(buffer), size);
 }
 
+void Stream::Flush() {
+  CheckClosed();
+  DoFlush();
+}
+
+bool Stream::DoCanSeek() {
+  if (supported_operations_->can_seek) {
+    return *supported_operations_->can_seek;
+  } else {
+    throw Exception(
+        u"Can seek is neither set in supported_operations nor implemeted in "
+        u"virtual function.");
+  }
+}
+
+bool Stream::DoCanRead() {
+  if (supported_operations_->can_read) {
+    return *supported_operations_->can_read;
+  } else {
+    throw Exception(
+        u"Can read is neither set in supported_operations nor implemeted in "
+        u"virtual function.");
+  }
+}
+
+bool Stream::DoCanWrite() {
+  if (supported_operations_->can_write) {
+    return *supported_operations_->can_write;
+  } else {
+    throw Exception(
+        u"Can write is neither set in supported_operations nor implemeted in "
+        u"virtual function.");
+  }
+}
+
+Index Stream::DoSeek(Index offset, SeekOrigin origin) {
+  throw Exception(u"Stream is seekable but DoSeek is not implemented.");
+}
+
+Index Stream::DoTell() {
+  StreamOperationNotSupportedException::CheckSeek(DoCanSeek());
+  return DoSeek(0, SeekOrigin::Current);
+}
+
+void Stream::DoRewind() {
+  StreamOperationNotSupportedException::CheckSeek(DoCanSeek());
+  DoSeek(0, SeekOrigin::Begin);
+}
+
+Index Stream::DoGetSize() {
+  StreamOperationNotSupportedException::CheckSeek(DoCanSeek());
+  Index current_position = DoTell();
+  Seek(0, SeekOrigin::End);
+  Index size = DoTell();
+  Seek(current_position, SeekOrigin::Begin);
+  return size;
+}
+
+Index Stream::DoRead(std::byte* buffer, Index offset, Index size) {
+  throw Exception(u"Stream is readable but DoSeek is not implemented.");
+}
+
+Index Stream::DoWrite(const std::byte* buffer, Index offset, Index size) {
+  throw Exception(u"Stream is writable but DoSeek is not implemented.");
+}
+
+void Stream::DoFlush() {}
+
 Buffer Stream::ReadToEnd(Index grow_size) {
   Buffer buffer(grow_size);
   while (true) {
@@ -77,8 +196,4 @@ String Stream::ReadToEndAsUtf8String() {
   auto buffer = ReadToEnd();
   return String::FromUtf8(buffer);
 }
-
-void Stream::Flush() {}
-
-void Stream::Close() {}
 }  // namespace cru::io