LibCore+Everywhere: Make Core::Stream::read() return Bytes

A mistake I've repeatedly made is along these lines:
```c++
auto nread = TRY(source_file->read(buffer));
TRY(destination_file->write(buffer));
```

It's a little clunky to have to create a Bytes or StringView from the
buffer's data pointer and the nread, and easy to forget and just use
the buffer. So, this patch changes the read() function to return a
Bytes of the data that were just read.

The other read_foo() methods will be modified in the same way in
subsequent commits.

Fixes #13687

5 files changed, 18 insertions, 18 deletions

diff --git a/Userland/Services/EchoServer/Client.cpp b/Userland/Services/EchoServer/Client.cpp
index 0a3ae489ba..2538ffa24f 100644
--- a/Userland/Services/EchoServer/Client.cpp
+++ b/Userland/Services/EchoServer/Client.cpp
@@ -30,16 +30,16 @@ ErrorOr<void> Client::drain_socket()
     auto buffer = TRY(ByteBuffer::create_uninitialized(1024));
 
     while (TRY(m_socket->can_read_without_blocking())) {
-        auto nread = TRY(m_socket->read(buffer));
+        auto bytes_read = TRY(m_socket->read(buffer));
 
-        dbgln("Read {} bytes.", nread);
+        dbgln("Read {} bytes.", bytes_read.size());
 
         if (m_socket->is_eof()) {
             Core::deferred_invoke([this, strong_this = NonnullRefPtr(*this)] { quit(); });
             break;
         }
 
-        TRY(m_socket->write({ buffer.data(), nread }));
+        TRY(m_socket->write(bytes_read));
     }
 
     return {};
diff --git a/Userland/Services/FileOperation/main.cpp b/Userland/Services/FileOperation/main.cpp
index f27caa229d..05f4432277 100644
--- a/Userland/Services/FileOperation/main.cpp
+++ b/Userland/Services/FileOperation/main.cpp
@@ -238,15 +238,15 @@ ErrorOr<int> execute_work_items(Vector<WorkItem> const& items)
             while (true) {
                 print_progress();
                 auto bytes_read = TRY(source_file->read(buffer.bytes()));
-                if (bytes_read == 0)
+                if (bytes_read.is_empty())
                     break;
-                if (auto result = destination_file->write(buffer); result.is_error()) {
+                if (auto result = destination_file->write(bytes_read); result.is_error()) {
                     // FIXME: Return the formatted string directly. There is no way to do this right now without the temporary going out of scope and being destroyed.
                     report_warning(String::formatted("Failed to write to destination file: {}", result.error()));
                     return result.error();
                 }
-                item_done += bytes_read;
-                executed_work_bytes += bytes_read;
+                item_done += bytes_read.size();
+                executed_work_bytes += bytes_read.size();
                 print_progress();
                 // FIXME: Remove this once the kernel is smart enough to schedule other threads
                 //        while we're doing heavy I/O. Right now, copying a large file will totally
diff --git a/Userland/Services/InspectorServer/InspectableProcess.cpp b/Userland/Services/InspectorServer/InspectableProcess.cpp
index 1b085db255..a709d180fe 100644
--- a/Userland/Services/InspectorServer/InspectableProcess.cpp
+++ b/Userland/Services/InspectorServer/InspectableProcess.cpp
@@ -43,8 +43,8 @@ String InspectableProcess::wait_for_response()
     }
 
     u32 length {};
-    auto nread = m_socket->read({ (u8*)&length, sizeof(length) }).release_value_but_fixme_should_propagate_errors();
-    if (nread != sizeof(length)) {
+    auto length_bytes_read = m_socket->read({ (u8*)&length, sizeof(length) }).release_value_but_fixme_should_propagate_errors();
+    if (length_bytes_read.size() != sizeof(length)) {
         dbgln("InspectableProcess got malformed data: PID {}", m_pid);
         m_socket->close();
         return {};
@@ -54,17 +54,17 @@ String InspectableProcess::wait_for_response()
     auto remaining_data_buffer = data_buffer.bytes();
 
     while (!remaining_data_buffer.is_empty()) {
-        auto maybe_nread = m_socket->read(remaining_data_buffer);
-        if (maybe_nread.is_error()) {
-            dbgln("InspectableProcess::wait_for_response: Failed to read data: {}", maybe_nread.error());
+        auto maybe_bytes_read = m_socket->read(remaining_data_buffer);
+        if (maybe_bytes_read.is_error()) {
+            dbgln("InspectableProcess::wait_for_response: Failed to read data: {}", maybe_bytes_read.error());
             break;
         }
 
-        auto nread = maybe_nread.release_value();
-        if (nread == 0)
+        auto bytes_read = maybe_bytes_read.release_value();
+        if (bytes_read.is_empty())
             break;
 
-        remaining_data_buffer = remaining_data_buffer.slice(nread);
+        remaining_data_buffer = remaining_data_buffer.slice(bytes_read.size());
     }
 
     VERIFY(data_buffer.size() == length);
diff --git a/Userland/Services/LookupServer/LookupServer.cpp b/Userland/Services/LookupServer/LookupServer.cpp
index c69749e401..5cea3bf57b 100644
--- a/Userland/Services/LookupServer/LookupServer.cpp
+++ b/Userland/Services/LookupServer/LookupServer.cpp
@@ -239,7 +239,7 @@ ErrorOr<Vector<Answer>> LookupServer::lookup(Name const& name, String const& nam
     TRY(udp_socket->write(buffer));
 
     u8 response_buffer[4096];
-    int nrecv = TRY(udp_socket->read({ response_buffer, sizeof(response_buffer) }));
+    int nrecv = TRY(udp_socket->read({ response_buffer, sizeof(response_buffer) })).size();
     if (udp_socket->is_eof())
         return Vector<Answer> {};
 
diff --git a/Userland/Services/TelnetServer/Client.cpp b/Userland/Services/TelnetServer/Client.cpp
index d45800975c..68dda4074d 100644
--- a/Userland/Services/TelnetServer/Client.cpp
+++ b/Userland/Services/TelnetServer/Client.cpp
@@ -76,9 +76,9 @@ ErrorOr<void> Client::drain_socket()
     auto buffer = TRY(ByteBuffer::create_uninitialized(1024));
 
     while (TRY(m_socket->can_read_without_blocking())) {
-        auto nread = TRY(m_socket->read(buffer));
+        auto read_bytes = TRY(m_socket->read(buffer));
 
-        m_parser.write({ buffer.data(), nread });
+        m_parser.write(StringView { read_bytes });
 
         if (m_socket->is_eof()) {
             Core::deferred_invoke([this, strong_this = NonnullRefPtr(*this)] { quit(); });