Support colored logs

Add a default logger implementation for log crate.
Add a new feature "log".

Cargo.toml

@@ -26,6 +26,7 @@ libc = []
 ckb2023 = []
 # work with `target-feature=-a` Cargo flag
 dummy-atomic = []
+log = ["dep:log", "dummy-atomic"]
 
 [build-dependencies]
 cc = "1.0"
@@ -35,6 +36,7 @@ ckb-types = { package = "ckb-gen-types", version = "0.116", default-features = f
 buddy-alloc = { version = "0.5.0", optional = true }
 ckb-x64-simulator = { version = "0.8", optional = true }
 gcd = "2.3.0"
+log = { version = "0.4.21", optional = true, default-features = false }
 
 [workspace]
 exclude = ["test"]

README.md

@@ -16,6 +16,7 @@ This library contains several modules that help you write CKB contract with Rust
 * `entry!` macro: defines contract entry point
 * `default_alloc!` macro: defines global allocator for no-std rust
 * `dummy_atomic` module: dummy atomic operations
+* `log` module: colored log
 ### Memory allocator
 
 Default allocator uses a mixed allocation strategy:

contracts/ckb-std-tests/Cargo.toml

@@ -6,7 +6,7 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-ckb-std = { path = "../../", features = [ "dlopen-c", "dummy-atomic" ] }
+ckb-std = { path = "../../", features = [ "dlopen-c", "dummy-atomic", "log"] }
 blake2b-ref = { version = "0.3", default-features = false }
 bytes = { version = "1.6.0", default-features = false }
 log = { version = "0.4.17", default-features = false }

contracts/ckb-std-tests/src/entry.rs

@@ -22,8 +22,6 @@ use ckb_std::{dynamic_loading, dynamic_loading_c_impl};
 use core::ffi::c_void;
 #[cfg(target_arch = "riscv64")]
 use core::mem::size_of_val;
-#[cfg(target_arch = "riscv64")]
-use log::{info, warn};
 
 fn new_blake2b() -> Blake2b {
     const CKB_HASH_PERSONALIZATION: &[u8] = b"ckb-default-hash";
@@ -423,8 +421,8 @@ fn test_atomic() {
     assert_eq!(v.len(), 4);
 
     // The log crate uses atomic operations.
-    info!("atomic info");
-    warn!("atomic warn");
+    log::info!("atomic info");
+    log::warn!("atomic warn");
 }
 
 #[cfg(target_arch = "riscv64")]
@@ -786,6 +784,16 @@ fn test_atomic2() {
     assert_eq!(data, 0xFFFFFFFFFFFFFFFE);
 }
 
+#[cfg(target_arch = "riscv64")]
+fn test_log() {
+    drop(ckb_std::log::init());
+    log::trace!("this is trace");
+    log::debug!("this is debug");
+    log::info!("this is info");
+    log::warn!("this is warn");
+    log::error!("this is error");
+}
+
 pub fn main() -> Result<(), Error> {
     test_basic();
     test_load_data();
@@ -812,6 +820,7 @@ pub fn main() -> Result<(), Error> {
     {
         test_atomic();
         test_atomic2();
+        test_log();
     }
     Ok(())
 }

src/lib.rs

@@ -38,3 +38,5 @@ pub mod dynamic_loading_c_impl;
 pub use buddy_alloc;
 #[cfg(feature = "dummy-atomic")]
 pub mod dummy_atomic;
+#[cfg(feature = "log")]
+pub mod log;

src/log.rs

@@ -0,0 +1,66 @@
+extern crate alloc;
+
+use crate::syscalls;
+use alloc::format;
+use log::{Level, Metadata, Record};
+use log::{LevelFilter, SetLoggerError};
+
+struct SimpleLogger;
+
+impl log::Log for SimpleLogger {
+    fn enabled(&self, _metadata: &Metadata) -> bool {
+        true
+    }
+
+    fn log(&self, record: &Record) {
+        let metadata = record.metadata();
+        if self.enabled(metadata) {
+            let level = metadata.level();
+            match level {
+                Level::Error => syscalls::debug(format!(
+                    "[\x1b[31m{}\x1b[0m {}:{}] {}",
+                    record.level(),
+                    record.file().unwrap_or("???"),
+                    record.line().unwrap_or(0),
+                    record.args()
+                )),
+                Level::Warn => syscalls::debug(format!(
+                    "[\x1b[33m{}\x1b[0m  {}:{}] {}",
+                    record.level(),
+                    record.file().unwrap_or("???"),
+                    record.line().unwrap_or(0),
+                    record.args()
+                )),
+                Level::Info => syscalls::debug(format!(
+                    "[\x1b[32m{}\x1b[0m  {}:{}] {}",
+                    record.level(),
+                    record.file().unwrap_or("???"),
+                    record.line().unwrap_or(0),
+                    record.args()
+                )),
+                Level::Debug => syscalls::debug(format!(
+                    "[\x1b[34m{}\x1b[0m {}:{}] {}",
+                    record.level(),
+                    record.file().unwrap_or("???"),
+                    record.line().unwrap_or(0),
+                    record.args()
+                )),
+                Level::Trace => syscalls::debug(format!(
+                    "[\x1b[36m{}\x1b[0m {}:{}] {}",
+                    record.level(),
+                    record.file().unwrap_or("???"),
+                    record.line().unwrap_or(0),
+                    record.args()
+                )),
+            }
+        }
+    }
+
+    fn flush(&self) {}
+}
+
+static LOGGER: SimpleLogger = SimpleLogger;
+
+pub fn init() -> Result<(), SetLoggerError> {
+    log::set_logger(&LOGGER).map(|()| log::set_max_level(LevelFilter::Trace))
+}