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

2 files changed, 24 insertions, 24 deletions

diff --git a/Tests/LibCore/TestLibCoreStream.cpp b/Tests/LibCore/TestLibCoreStream.cpp
index 37d559bcb0..b8a47283d0 100644
--- a/Tests/LibCore/TestLibCoreStream.cpp
+++ b/Tests/LibCore/TestLibCoreStream.cpp
@@ -63,7 +63,7 @@ TEST_CASE(file_read_bytes)
 
     auto result = file->read(buffer);
     EXPECT(!result.is_error());
-    EXPECT_EQ(result.value(), 131ul);
+    EXPECT_EQ(result.value().size(), 131ul);
 
     StringView buffer_contents { buffer.bytes() };
     EXPECT_EQ(buffer_contents, expected_buffer_contents);
@@ -193,11 +193,11 @@ TEST_CASE(tcp_socket_read)
     auto maybe_receive_buffer = ByteBuffer::create_uninitialized(64);
     EXPECT(!maybe_receive_buffer.is_error());
     auto receive_buffer = maybe_receive_buffer.release_value();
-    auto maybe_nread = client_socket->read(receive_buffer);
-    EXPECT(!maybe_nread.is_error());
-    auto nread = maybe_nread.release_value();
+    auto maybe_read_bytes = client_socket->read(receive_buffer);
+    EXPECT(!maybe_read_bytes.is_error());
+    auto read_bytes = maybe_read_bytes.release_value();
 
-    StringView received_data { receive_buffer.data(), nread };
+    StringView received_data { read_bytes };
     EXPECT_EQ(sent_data, received_data);
 }
 
@@ -226,11 +226,11 @@ TEST_CASE(tcp_socket_write)
     auto maybe_receive_buffer = ByteBuffer::create_uninitialized(64);
     EXPECT(!maybe_receive_buffer.is_error());
     auto receive_buffer = maybe_receive_buffer.release_value();
-    auto maybe_nread = server_socket->read(receive_buffer);
-    EXPECT(!maybe_nread.is_error());
-    auto nread = maybe_nread.release_value();
+    auto maybe_read_bytes = server_socket->read(receive_buffer);
+    EXPECT(!maybe_read_bytes.is_error());
+    auto read_bytes = maybe_read_bytes.release_value();
 
-    StringView received_data { receive_buffer.data(), nread };
+    StringView received_data { read_bytes };
     EXPECT_EQ(sent_data, received_data);
 }
 
@@ -262,7 +262,7 @@ TEST_CASE(tcp_socket_eof)
     auto maybe_receive_buffer = ByteBuffer::create_uninitialized(1);
     EXPECT(!maybe_receive_buffer.is_error());
     auto receive_buffer = maybe_receive_buffer.release_value();
-    EXPECT_EQ(client_socket->read(receive_buffer).release_value(), 0ul);
+    EXPECT(client_socket->read(receive_buffer).release_value().is_empty());
     EXPECT(client_socket->is_eof());
 }
 
@@ -309,11 +309,11 @@ TEST_CASE(udp_socket_read_write)
     auto maybe_client_receive_buffer = ByteBuffer::create_uninitialized(64);
     EXPECT(!maybe_client_receive_buffer.is_error());
     auto client_receive_buffer = maybe_client_receive_buffer.release_value();
-    auto maybe_nread = client_socket->read(client_receive_buffer);
-    EXPECT(!maybe_nread.is_error());
-    auto nread = maybe_nread.release_value();
+    auto maybe_read_bytes = client_socket->read(client_receive_buffer);
+    EXPECT(!maybe_read_bytes.is_error());
+    auto read_bytes = maybe_read_bytes.release_value();
 
-    StringView client_received_data { client_receive_buffer.data(), nread };
+    StringView client_received_data { read_bytes };
     EXPECT_EQ(udp_reply_data, client_received_data);
 }
 
@@ -353,11 +353,11 @@ TEST_CASE(local_socket_read)
             auto maybe_receive_buffer = ByteBuffer::create_uninitialized(64);
             EXPECT(!maybe_receive_buffer.is_error());
             auto receive_buffer = maybe_receive_buffer.release_value();
-            auto maybe_nread = client_socket->read(receive_buffer);
-            EXPECT(!maybe_nread.is_error());
-            auto nread = maybe_nread.release_value();
+            auto maybe_read_bytes = client_socket->read(receive_buffer);
+            EXPECT(!maybe_read_bytes.is_error());
+            auto read_bytes = maybe_read_bytes.release_value();
 
-            StringView received_data { receive_buffer.data(), nread };
+            StringView received_data { read_bytes };
             EXPECT_EQ(sent_data, received_data);
 
             return 0;
@@ -384,11 +384,11 @@ TEST_CASE(local_socket_write)
         auto maybe_receive_buffer = ByteBuffer::create_uninitialized(pending_bytes);
         EXPECT(!maybe_receive_buffer.is_error());
         auto receive_buffer = maybe_receive_buffer.release_value();
-        auto maybe_nread = server_socket->read(receive_buffer);
-        EXPECT(!maybe_nread.is_error());
-        EXPECT_EQ(maybe_nread.value(), sent_data.length());
+        auto maybe_read_bytes = server_socket->read(receive_buffer);
+        EXPECT(!maybe_read_bytes.is_error());
+        EXPECT_EQ(maybe_read_bytes.value().size(), sent_data.length());
 
-        StringView received_data { receive_buffer.data(), maybe_nread.value() };
+        StringView received_data { maybe_read_bytes.value() };
         EXPECT_EQ(sent_data, received_data);
 
         event_loop.quit(0);
diff --git a/Tests/LibTLS/TestTLSHandshake.cpp b/Tests/LibTLS/TestTLSHandshake.cpp
index a02a668884..2bc5ee1988 100644
--- a/Tests/LibTLS/TestTLSHandshake.cpp
+++ b/Tests/LibTLS/TestTLSHandshake.cpp
@@ -79,8 +79,8 @@ TEST_CASE(test_TLS_hello_handshake)
     auto tls = MUST(TLS::TLSv12::connect(DEFAULT_SERVER, port, move(options)));
     ByteBuffer contents;
     tls->on_ready_to_read = [&] {
-        auto nread = MUST(tls->read(contents.must_get_bytes_for_writing(4 * KiB)));
-        if (nread == 0) {
+        auto read_bytes = MUST(tls->read(contents.must_get_bytes_for_writing(4 * KiB)));
+        if (read_bytes.is_empty()) {
             FAIL("No data received");
             loop.quit(1);
         }