Add wrapper for configuration set/get

Author: mulimoen

netcdf-sys/build.rs

@@ -306,6 +306,10 @@ fn main() {
                 "cargo:rustc-cfg=feature=\"{}.{}.{}\"",
                 version.major, version.minor, version.patch
             );
+            println!(
+                "cargo:version_\"{}.{}.{}\"=1",
+                version.major, version.minor, version.patch
+            );
         }
     }
     metaheader.emit_feature_flags();

netcdf/Cargo.toml

@@ -23,6 +23,7 @@ static = ["netcdf-sys/static"]
 ndarray = { version = "0.15", optional = true }
 netcdf-sys = { workspace = true }
 bitflags = "2.4.2"
+libc = "0.2.154"
 
 [dev-dependencies]
 clap = { version = "4.5.1", features = ["derive"] }

netcdf/build.rs

@@ -2,4 +2,9 @@ fn main() {
     if std::env::var("DEP_NETCDF_HAS_MMAP").is_ok() {
         println!("cargo:rustc-cfg=feature=\"has-mmap\"");
     }
+    for (env, _value) in std::env::vars() {
+        if let Some(version) = env.strip_prefix("DEP_NETCDF_VERSION_") {
+            println!("cargo:rustc-cfg=feature={version}");
+        }
+    }
 }

netcdf/src/lib.rs

@@ -110,6 +110,8 @@ pub(crate) mod error;
 pub(crate) mod extent;
 pub(crate) mod file;
 pub(crate) mod group;
+#[cfg(feature = "4.9.2")]
+pub mod rc;
 pub mod types;
 pub(crate) mod variable;
 

netcdf/src/rc.rs

@@ -0,0 +1,42 @@
+use std::ffi::{c_char, CStr, CString};
+use std::ops::Deref;
+use std::ptr::NonNull;
+
+pub fn set(key: &str, value: &str) -> crate::error::Result<()> {
+    let key = CString::new(key)?;
+    let value = CString::new(value)?;
+    crate::error::checked(crate::with_lock(|| unsafe {
+        netcdf_sys::nc_rc_set(key.as_ptr(), value.as_ptr())
+    }))
+}
+
+#[derive(Debug)]
+pub struct OwnedString {
+    inner: NonNull<c_char>,
+}
+
+impl Deref for OwnedString {
+    type Target = CStr;
+    fn deref(&self) -> &Self::Target {
+        unsafe { CStr::from_ptr(self.inner.as_ptr()) }
+    }
+}
+
+impl Drop for OwnedString {
+    fn drop(&mut self) {
+        unsafe {
+            libc::free(self.inner.as_ptr().cast());
+        }
+    }
+}
+
+pub fn get(key: &str) -> Option<OwnedString> {
+    let key = if let Ok(key) = CString::new(key) {
+        key
+    } else {
+        return None;
+    };
+    let _lock = netcdf_sys::libnetcdf_lock.lock().unwrap();
+    let value = unsafe { netcdf_sys::nc_rc_get(key.as_ptr()) };
+    NonNull::new(value).map(|inner| OwnedString { inner })
+}