Support `logger::Record` in C by String-ing the fmt::Arguments

This adds a new (non-feature) cfg argument `c_bindings` which will
be set when building C bindings. With this, we can (slightly) tweak
behavior and API based on whether we are being built for Rust or C
users.

Ideally we'd never need this, but as long as we can keep the API
consistent-enough to avoid material code drift, this gives us a
cheap way of doing the "right" thing for both C and Rust when the
two are in tension.

We also move lightning-background-processor to support the same
MSRV as the main lightning crate, instead of only
lightning-net-tokio's MSRV.

This is a backport of 016eb96fc7170bdbab238292d3cc9338c2a66eb9

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 34337769a26677969bc8a3246c4cbb36f35648f7..45084bbd5e051966cd6116b39f18dbf27e70f512 100644 (file)
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -115,6 +115,14 @@ jobs:
           cargo test --verbose --color always  -p lightning
           cargo test --verbose --color always  -p lightning-invoice
           cargo build --verbose  --color always -p lightning-persister
+          cargo build --verbose  --color always -p lightning-background-processor
+      - name: Test C Bindings Modifications on Rust ${{ matrix.toolchain }}
+        if: "! matrix.build-net-tokio"
+        run: |
+          RUSTFLAGS="--cfg=c_bindings" cargo test --verbose --color always  -p lightning
+          RUSTFLAGS="--cfg=c_bindings" cargo test --verbose --color always  -p lightning-invoice
+          RUSTFLAGS="--cfg=c_bindings" cargo build --verbose  --color always -p lightning-persister
+          RUSTFLAGS="--cfg=c_bindings" cargo build --verbose  --color always -p lightning-background-processor
       - name: Test Block Sync Clients on Rust ${{ matrix.toolchain }} with features
         if: "matrix.build-net-tokio && !matrix.coverage"
         run: |

diff --git a/lightning/src/util/logger.rs b/lightning/src/util/logger.rs
index 2717effb209d94750b1965a28c64a856647f3d80..7f85f715914dd1c2219eef02730c3494cb0a0b78 100644 (file)
--- a/lightning/src/util/logger.rs
+++ b/lightning/src/util/logger.rs
@@ -84,32 +84,45 @@ impl Level {
 
 /// A Record, unit of logging output with Metadata to enable filtering
 /// Module_path, file, line to inform on log's source
-/// (C-not exported) - we convert to a const char* instead
-#[derive(Clone,Debug)]
+#[derive(Clone, Debug)]
 pub struct Record<'a> {
        /// The verbosity level of the message.
        pub level: Level,
+       #[cfg(not(c_bindings))]
        /// The message body.
        pub args: fmt::Arguments<'a>,
+       #[cfg(c_bindings)]
+       /// The message body.
+       pub args: String,
        /// The module path of the message.
-       pub module_path: &'a str,
+       pub module_path: &'static str,
        /// The source file containing the message.
-       pub file: &'a str,
+       pub file: &'static str,
        /// The line containing the message.
        pub line: u32,
+
+       #[cfg(c_bindings)]
+       /// We don't actually use the lifetime parameter in C bindings (as there is no good way to
+       /// communicate a lifetime to a C, or worse, Java user).
+       _phantom: core::marker::PhantomData<&'a ()>,
 }
 
 impl<'a> Record<'a> {
        /// Returns a new Record.
        /// (C-not exported) as fmt can't be used in C
        #[inline]
-       pub fn new(level: Level, args: fmt::Arguments<'a>, module_path: &'a str, file: &'a str, line: u32) -> Record<'a> {
+       pub fn new(level: Level, args: fmt::Arguments<'a>, module_path: &'static str, file: &'static str, line: u32) -> Record<'a> {
                Record {
                        level,
+                       #[cfg(not(c_bindings))]
                        args,
+                       #[cfg(c_bindings)]
+                       args: format!("{}", args),
                        module_path,
                        file,
-                       line
+                       line,
+                       #[cfg(c_bindings)]
+                       _phantom: core::marker::PhantomData,
                }
        }
 }