Replace the built-in defmt debug logging to the platform trait

This way we don't have to add defmt, esp32-println and others as features to corelib and the slint api crate (which would also expose them as public dependencies), but instead this can be simply delegated to the Platform trait.
task-jp · Sep 2, 2022 · 437218d · 437218d
1 parent deee971
commit 437218d
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Showing 7 changed files with 39 additions and 40 deletions.
diff --git a/api/rs/slint/Cargo.toml b/api/rs/slint/Cargo.toml
@@ -86,10 +86,6 @@ renderer-software = [
 ## This feature is an alias for `backend-qt`
 renderer-qt = ["backend-qt"]
 
-## This feature enables debug output to be sent via the [deferred formatting framework](https://defmt.ferrous-systems.com).
-## Use this in MCU environments where defmt is supported.
-defmt = ["i-slint-core/defmt"]
-
 ## This feature enables floating point arithmetic emulation using the [libm](https://crates.io/crates/libm) crate. Use this
 ## in MCU environments where the processor does not support floating point arithmetic.
 libm = ["i-slint-core/libm"]

diff --git a/examples/mcu-board-support/Cargo.toml b/examples/mcu-board-support/Cargo.toml
@@ -17,8 +17,8 @@ links = "mcu_board_support" # just so we can pass metadata to the slint build cr
 path = "lib.rs"
 
 [features]
-pico-st7789 = ["slint/unsafe-single-threaded", "rp-pico", "embedded-hal", "cortex-m-rt", "alloc-cortex-m", "fugit", "cortex-m", "cortex-m", "display-interface", "st7789", "defmt", "defmt-rtt",  "slint/defmt", "shared-bus", "slint/libm", "embedded-dma", "embedded-graphics", "euclid/libm"]
-stm32h735g = ["slint/unsafe-single-threaded", "embedded-hal", "cortex-m-rt", "alloc-cortex-m", "embedded-time", "cortex-m", "slint/defmt", "stm32h7xx-hal/stm32h735", "defmt", "defmt-rtt", "embedded-display-controller", "ft5336", "panic-probe", "slint/libm"]
+pico-st7789 = ["slint/unsafe-single-threaded", "rp-pico", "embedded-hal", "cortex-m-rt", "alloc-cortex-m", "fugit", "cortex-m", "cortex-m", "display-interface", "st7789", "defmt", "defmt-rtt",  "shared-bus", "slint/libm", "embedded-dma", "embedded-graphics", "euclid/libm"]
+stm32h735g = ["slint/unsafe-single-threaded", "embedded-hal", "cortex-m-rt", "alloc-cortex-m", "embedded-time", "cortex-m", "stm32h7xx-hal/stm32h735", "defmt", "defmt-rtt", "embedded-display-controller", "ft5336", "panic-probe", "slint/libm"]
 esp32-s2-kaluga-1 = ["slint/unsafe-single-threaded", "esp32s2-hal", "embedded-hal", "xtensa-lx-rt", "esp-alloc", "esp-println", "display-interface", "display-interface-spi", "st7789", "slint/libm"]
 
 [dependencies]

diff --git a/examples/mcu-board-support/pico_st7789.rs b/examples/mcu-board-support/pico_st7789.rs
@@ -261,6 +261,10 @@ impl slint::platform::Platform for PicoBackend {
             cortex_m::asm::wfe();
         }
     }
+
+    fn debug_log(&self, text: &str) {
+        defmt::println!("{=str}", text);
+    }
 }
 
 enum PioTransfer<TO: WriteTarget, CH: SingleChannel> {

diff --git a/examples/mcu-board-support/stm32h735g.rs b/examples/mcu-board-support/stm32h735g.rs
@@ -361,4 +361,8 @@ impl slint::platform::Platform for StmBackend {
         let val = self.timer.get().map_or(0, |t| t.counter() / 10);
         core::time::Duration::from_millis(val.into())
     }
+
+    fn debug_log(&self, text: &str) {
+        defmt::println!("{=str}", text);
+    }
 }
diff --git a/internal/core/Cargo.toml b/internal/core/Cargo.toml
@@ -51,7 +51,6 @@ vtable = { version="0.1.9", path = "../../helper_crates/vtable" }
 atomic-polyfill = "1.0.1"
 auto_enums = "0.7"
 cfg-if = "1"
-defmt = { version = "0.3.0", optional = true }
 derive_more = "0.99.5"
 euclid = { version = "0.22.1", default-features = false }
 instant = { version = "0.1", features = [ "now" ], optional = true }

diff --git a/internal/core/platform.rs b/internal/core/platform.rs
@@ -72,6 +72,27 @@ pub trait Platform {
     fn clipboard_text(&self) -> Option<String> {
         None
     }
+
+    /// This function is called when debug() is used in .slint files. The implementation
+    /// should direct the output to some developer visible terminal. The default implementation
+    /// uses stderr if available, or `console.log` when targeting wasm.
+    fn debug_log(&self, _text: &str) {
+        cfg_if::cfg_if! {
+            if #[cfg(target_arch = "wasm32")] {
+                use wasm_bindgen::prelude::*;
+
+                #[wasm_bindgen]
+                extern "C" {
+                    #[wasm_bindgen(js_namespace = console)]
+                    pub fn log(s: &str);
+                }
+
+                log(_text);
+            } else if #[cfg(feature = "std")] {
+                eprintln!("{}", _text);
+            }
+        }
+    }
 }
 
 /// Trait that is returned by the [`Platform::new_event_loop_proxy`]
@@ -103,7 +124,8 @@ impl std::convert::From<crate::animations::Instant> for instant::Instant {
 }
 
 thread_local! {
-    pub(crate) static PLATFORM_INSTANCE : once_cell::unsync::OnceCell<Box<dyn Platform>>
+    /// Internal: Singleton of the platform abstraction.
+    pub static PLATFORM_INSTANCE : once_cell::unsync::OnceCell<Box<dyn Platform>>
         = once_cell::unsync::OnceCell::new()
 }
 static EVENTLOOP_PROXY: OnceCell<Box<dyn EventLoopProxy + 'static>> = OnceCell::new();

diff --git a/internal/core/tests.rs b/internal/core/tests.rs
@@ -84,47 +84,21 @@ pub extern "C" fn send_keyboard_string_sequence(
 }
 
 cfg_if::cfg_if! {
-    if #[cfg(target_arch = "wasm32")] {
-        use wasm_bindgen::prelude::*;
-
-        #[wasm_bindgen]
-        extern "C" {
-            #[wasm_bindgen(js_namespace = console)]
-            pub fn log(s: &str);
-        }
 
+    if #[cfg(feature = "std")] {
         #[macro_export]
         /// This macro allows producing debug output that will appear on stderr in regular builds
         /// and in the console log for wasm builds.
         macro_rules! debug_log {
-            ($($t:tt)*) => ($crate::tests::log(&format_args!($($t)*).to_string()))
-        }
-    } else if #[cfg(feature = "std")] {
-        #[doc(hidden)]
-        pub use std::eprintln;
-
-        /// This macro allows producing debug output that will appear on stderr in regular builds
-        /// and in the console log for wasm builds.
-        #[macro_export]
-        macro_rules! debug_log {
-            ($($t:tt)*) => ($crate::tests::eprintln!($($t)*))
-        }
-    } else if #[cfg(feature = "defmt")] {
-        #[doc(hidden)]
-        pub fn log(s: &str) {
-            defmt::println!("{=str}", s);
-        }
-
-        #[macro_export]
-        /// This macro allows producing debug output that will appear on the output of the debug probe
-        macro_rules! debug_log {
-            ($($t:tt)*) => ($crate::tests::log({ use alloc::string::ToString; &format_args!($($t)*).to_string() }))
+            ($($t:tt)*) => ($crate::platform::PLATFORM_INSTANCE.with(|p| {p.get().map(|p| p.debug_log(&format_args!($($t)*).to_string()));}))
         }
     } else {
         #[macro_export]
-        /// Do nothing
+        /// This macro allows producing debug output that will appear on stderr in regular builds
+        /// and in the console log for wasm builds.
         macro_rules! debug_log {
-            ($($t:tt)*) => (let _ = &format_args!($($t)*);)
+            ($($t:tt)*) => ($crate::platform::PLATFORM_INSTANCE.with(|p| { use alloc::string::ToString; p.get().map(|p| p.debug_log(&format_args!($($t)*).to_string()));}))
         }
     }
+
 }