1 // Copyright 2024, The Android Open Source Project 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 //! Rust wrapper for `EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL`. 16 17 use crate::efi_call; 18 use crate::protocol::{Protocol, ProtocolInfo}; 19 use core::fmt::Write; 20 use efi_types::{char16_t, EfiGuid, EfiSimpleTextOutputProtocol}; 21 use liberror::Result; 22 23 /// EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL 24 pub struct SimpleTextOutputProtocol; 25 26 impl ProtocolInfo for SimpleTextOutputProtocol { 27 type InterfaceType = EfiSimpleTextOutputProtocol; 28 29 const GUID: EfiGuid = 30 EfiGuid::new(0x387477c2, 0x69c7, 0x11d2, [0x8e, 0x39, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b]); 31 } 32 33 impl Protocol<'_, SimpleTextOutputProtocol> { 34 /// Wrapper of `EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL.OutputString()` output_string(&self, msg: *mut char16_t) -> Result<()>35 pub fn output_string(&self, msg: *mut char16_t) -> Result<()> { 36 // SAFETY: 37 // `self.interface()?` guarantees `self.interface` is non-null and points to a valid object 38 // established by `Protocol::new()`. 39 // `self.interface` is input parameter and will not be retained. It outlives the call. 40 unsafe { efi_call!(self.interface()?.output_string, self.interface, msg) } 41 } 42 } 43 44 /// Implement formatted write for `EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL`, so that we can print by 45 /// writing to it. i.e.: 46 /// 47 /// ``` 48 /// let protocol: Protocol<SimpleTextOutputProtocol> = ...; 49 /// write!(protocol, "Value = {}\n", 1234); 50 /// ``` 51 impl Write for Protocol<'_, SimpleTextOutputProtocol> { write_str(&mut self, s: &str) -> core::fmt::Result52 fn write_str(&mut self, s: &str) -> core::fmt::Result { 53 for ch in s.chars() { 54 // 2 is enough for encode_utf16(). Add an additional one as NULL. 55 let mut buffer = [0u16; 3]; 56 let char16_msg = ch.encode_utf16(&mut buffer[..]); 57 self.output_string(char16_msg.as_mut_ptr()).map_err(|_| core::fmt::Error {})?; 58 } 59 Ok(()) 60 } 61 } 62