Growth ring const function checks (#383)

growth-ring/Cargo.toml

@@ -31,3 +31,6 @@ tokio = { version = "1.28.1", features = ["tokio-macros", "rt", "macros"] }
 name = "growthring"
 path = "src/lib.rs"
 crate-type = ["dylib", "rlib", "staticlib"]
+
+[lints.clippy]
+missing_const_for_fn = "warn"

growth-ring/src/wal.rs

@@ -86,7 +86,7 @@ fn sort_fids(file_nbit: u64, mut fids: Vec<u64>) -> Vec<(u8, u64)> {
     }
 }
 
-fn counter_lt(a: u32, b: u32) -> bool {
+const fn counter_lt(a: u32, b: u32) -> bool {
     if u32::abs_diff(a, b) > u32::MAX / 2 {
         b < a
     } else {
@@ -125,10 +125,10 @@ impl WalRingId {
             counter: 0,
         }
     }
-    pub fn get_start(&self) -> WalPos {
+    pub const fn get_start(&self) -> WalPos {
         self.start
     }
-    pub fn get_end(&self) -> WalPos {
+    pub const fn get_end(&self) -> WalPos {
         self.end
     }
 }

growth-ring/tests/common/mod.rs

@@ -20,7 +20,7 @@ pub trait FailGen {
 struct FileContentEmul(RefCell<Vec<u8>>);
 
 impl FileContentEmul {
-    pub fn new() -> Self {
+    pub const fn new() -> Self {
         FileContentEmul(RefCell::new(Vec::new()))
     }
 }
@@ -187,7 +187,7 @@ pub struct SingleFailGen {
 }
 
 impl SingleFailGen {
-    pub fn new(fail_point: usize) -> Self {
+    pub const fn new(fail_point: usize) -> Self {
         SingleFailGen {
             cnt: std::cell::Cell::new(0),
             fail_point,
@@ -214,7 +214,7 @@ impl FailGen for ZeroFailGen {
 pub struct CountFailGen(std::cell::Cell<usize>);
 
 impl CountFailGen {
-    pub fn new() -> Self {
+    pub const fn new() -> Self {
         CountFailGen(std::cell::Cell::new(0))
     }
     pub fn get_count(&self) -> usize {
@@ -234,7 +234,7 @@ impl FailGen for CountFailGen {
 pub struct PaintStrokes(Vec<(u32, u32, u32)>);
 
 impl PaintStrokes {
-    pub fn new() -> Self {
+    pub const fn new() -> Self {
         PaintStrokes(Vec::new())
     }