Merge pull request #39 from WiresmithTech/feature/#35-error-wrapping

Feature/#35 error wrapping

changelog.md

@@ -8,8 +8,8 @@
 
 * Added support for `LVStatusCode` and retrieving error descriptions from LabVIEW.
 * Added api for accessing dimensions of arrays.
+* Add API to error clusters to execute the rust code following the LabVIEW error semantics.
 * Lazily load LabVIEW functions to allow time for LabVIEW to load.
-
 #### Fixes
 
 * Expose NumericArrayResize trait to users of the Library.

labview-interop/src/errors.rs

@@ -55,32 +55,42 @@
 //! This enum has custom errors for our internal use, we can hold MgErrors, and as last resort we can also hold
 //! LVError
 
-use thiserror::Error;
-
 use crate::types::LVStatusCode;
-
 use num_enum::{IntoPrimitive, TryFromPrimitive};
+use thiserror::Error;
 
 /// the conversion from LVInteropError back to LVStatusCode is important
 /// to return the status in extern "C" functions back to LV
 impl<T> From<Result<T>> for LVStatusCode {
     fn from(value: Result<T>) -> Self {
         match value {
             Ok(_) => LVStatusCode::SUCCESS,
-            Err(err) => err.into(),
+            Err(err) => (&err).into(),
         }
     }
 }
-impl From<LVInteropError> for LVStatusCode {
-    fn from(value: LVInteropError) -> Self {
+impl From<&LVInteropError> for LVStatusCode {
+    fn from(value: &LVInteropError) -> Self {
         match value {
             LVInteropError::LabviewMgError(e) => e.into(),
-            LVInteropError::InternalError(e) => e.into(), // TODO
-            LVInteropError::LabviewError(e) => e,
+            LVInteropError::InternalError(e) => e.into(),
+            LVInteropError::LabviewError(e) => *e,
         }
     }
 }
 
+impl From<LVInteropError> for LVStatusCode {
+    fn from(value: LVInteropError) -> Self {
+        (&value).into()
+    }
+}
+
+impl From<LVStatusCode> for LVInteropError {
+    fn from(status: LVStatusCode) -> Self {
+        LVInteropError::LabviewError(status)
+    }
+}
+
 /// MgError is the subset of LabVIEW errors that may occur when dealing with the memory manager
 /// So in the context of Rust-LabVIEW-interop these are the kind of labview errors we may trigger within the library
 ///
@@ -344,10 +354,16 @@ impl TryFrom<LVStatusCode> for MgError {
     }
 }
 
+impl From<&MgError> for LVStatusCode {
+    fn from(errcode: &MgError) -> LVStatusCode {
+        let erri32: i32 = *errcode as i32;
+        erri32.into()
+    }
+}
+
 impl From<MgError> for LVStatusCode {
     fn from(errcode: MgError) -> LVStatusCode {
-        let erri32: i32 = errcode.into();
-        erri32.into()
+        (&errcode).into()
     }
 }
 
@@ -399,8 +415,8 @@ pub enum InternalError {
     InvalidMgErrorCode = 542_006,
 }
 
-impl From<InternalError> for LVStatusCode {
-    fn from(err: InternalError) -> LVStatusCode {
+impl From<&InternalError> for LVStatusCode {
+    fn from(err: &InternalError) -> LVStatusCode {
         let err_i32: i32 = match err {
             InternalError::Misc => 542_000,
             InternalError::NoLabviewApi(_) => 542_001,

labview-interop/src/types/boolean.rs

@@ -8,6 +8,10 @@
 ///
 /// You can use `.into()` to convert between this and
 /// rust [`bool`] types.
+///
+/// NOTE: This does not seem to work if the boolean is
+/// used as a parameter in a call library function node.
+/// In that case you should convert to numeric first.
 #[repr(transparent)]
 #[derive(PartialEq, Eq, Clone, Copy, Debug)]
 pub struct LVBool(u8);
@@ -65,4 +69,19 @@ mod tests {
         let value: bool = LVBool(23).into();
         assert_eq!(value, true)
     }
+
+    #[test]
+    fn lv_bool_in_if_statement() {
+        if LV_TRUE.into() {
+            assert!(true);
+        } else {
+            assert!(false);
+        }
+
+        if LV_FALSE.into() {
+            assert!(false);
+        } else {
+            assert!(true);
+        }
+    }
 }

labview-interop/src/types/lv_errors.rs

@@ -2,8 +2,6 @@
 //!
 //! This is only available in 64 bit currently due to restrictions
 //! on unaligned pointer access.
-use std::borrow::Cow;
-
 #[cfg(feature = "link")]
 use crate::errors::Result;
 use crate::errors::{LVInteropError, MgError};
@@ -12,6 +10,7 @@ use crate::memory::UPtr;
 use crate::types::LStrHandle;
 use crate::types::LVBool;
 use crate::types::LVStatusCode;
+use std::borrow::Cow;
 
 labview_layout!(
     /// The cluster format used by LabVIEW for transmitting errors.
@@ -22,12 +21,19 @@ labview_layout!(
     }
 );
 
+impl<'a> ErrorCluster<'a> {
+    /// Does the error cluster contain an error.
+    pub fn is_err(&self) -> bool {
+        self.status.into()
+    }
+}
+
 /// The pointer as passed by LabVIEW when using "Handles By Value" for type.
 ///
 /// Debugging shows only one level of indirection hence UPtr here.
 ///
 /// It is recommended to manually call `ErrorClusterPtr::as_ref` or `ErrorClusterPtr::as_mut`
-/// so that null pointeres can be detected.
+/// so that null pointers can be detected.
 ///
 /// Many string manipulation functions are only available with the `link` feature enabled so
 /// it can manipulate LabVIEW Strings.
@@ -44,6 +50,92 @@ fn format_error_source(source: &str, description: &str) -> String {
     }
 }
 
+#[cfg(feature = "link")]
+impl ErrorClusterPtr<'_> {
+    /// Wrap the provided function in error handling to match LabVIEW semantics.
+    ///
+    /// i.e. no execution on error in, convert return errors into error cluster.
+    ///
+    /// ## Parameters
+    ///
+    /// - `return_on_error` - The value to return if an error.
+    /// - `function` - The function to wrap. This is intended to be a closure for
+    ///   easy use.
+    ///
+    /// ## Example
+    ///
+    /// ```rust
+    /// use labview_interop::types::ErrorClusterPtr;
+    /// use labview_interop::errors::LVInteropError;
+    /// use labview_interop::types::LStrHandle;
+    ///
+    /// #[no_mangle]
+    /// pub extern "C" fn example_function(mut error_cluster: ErrorClusterPtr, mut string_input: LStrHandle) -> i32 {
+    ///   error_cluster.wrap_function(42, || -> Result<i32, LVInteropError> {
+    ///    // Do some work
+    ///    string_input.set_str("Hello World")?;
+    ///   Ok(42)
+    ///  })
+    /// }
+    /// ```
+    pub fn wrap_function<R, E: ToLvError, F: FnOnce() -> std::result::Result<R, E>>(
+        &mut self,
+        return_on_error: R,
+        function: F,
+    ) -> R {
+        if self.is_err() {
+            return return_on_error;
+        }
+        match function() {
+            Ok(value) => value,
+            Err(error) => {
+                let _ = error.write_error(self);
+                return_on_error
+            }
+        }
+    }
+
+    /// Wrap the provided function in error handling to match LabVIEW semantics.
+    ///
+    /// i.e. no execution on error in, convert return errors into error cluster.
+    ///
+    /// This version returns the LabVIEW status code of the error.
+    /// To return a different value, see [`ErrorClusterPtr::wrap_function`].
+    ///
+    /// ## Parameters
+    ///
+    /// - `function` - The function to wrap. This is intended to be a closure for
+    ///   easy use.
+    ///
+    /// ## Example
+    ///
+    /// ```rust
+    /// use labview_interop::types::{ErrorClusterPtr, LVStatusCode};
+    /// use labview_interop::errors::LVInteropError;
+    /// use labview_interop::types::LStrHandle;
+    ///
+    /// #[no_mangle]
+    /// pub extern "C" fn example_function(mut error_cluster: ErrorClusterPtr, mut string_input: LStrHandle) -> LVStatusCode {
+    ///   error_cluster.wrap_return_status(|| -> Result<(), LVInteropError> {
+    ///    // Do some work
+    ///    string_input.set_str("Hello World")?;
+    ///     Ok(())
+    ///
+    ///  })
+    /// }
+    /// ```
+    pub fn wrap_return_status<E: ToLvError, F: FnOnce() -> std::result::Result<(), E>>(
+        &mut self,
+        function: F,
+    ) -> LVStatusCode {
+        if self.is_err() {
+            return self.code;
+        }
+        self.wrap_function((), function);
+        self.code
+    }
+}
+
 #[cfg(feature = "link")]
 mod error_cluster_link_features {
     use super::*;
@@ -89,7 +181,7 @@ mod error_cluster_link_features {
 pub trait ToLvError {
     /// The code for the error. Default is 42.
     fn code(&self) -> LVStatusCode {
-        MgError::BogusError.into() // code 42, Generic Error
+        (&MgError::BogusError).into() // code 42, Generic Error
     }
 
     /// True if is error. Default is true.
@@ -112,7 +204,7 @@ pub trait ToLvError {
     ///
     /// This requires the `link` feature to enable string manipulation.
     #[cfg(feature = "link")]
-    fn write_error(&self, error_cluster: ErrorClusterPtr) -> Result<()> {
+    fn write_error(&self, error_cluster: &mut ErrorClusterPtr) -> Result<()> {
         let cluster = unsafe { error_cluster.as_ref_mut()? };
         let code = self.code();
         let source = self.source();
@@ -128,6 +220,16 @@ pub trait ToLvError {
 }
 
 impl ToLvError for LVInteropError {
+    fn code(&self) -> LVStatusCode {
+        self.into()
+    }
+    fn source(&self) -> Cow<'_, str> {
+        std::error::Error::source(self)
+            .map(|s| s.to_string())
+            .unwrap_or_default()
+            .into()
+    }
+
     fn description(&self) -> Cow<'_, str> {
         self.to_string().into()
     }

labview-test-library/src/error_clusters.rs

@@ -1,3 +1,4 @@
+use labview_interop::errors::LVInteropError;
 /// A simple type for testing the error integration.
 ///
 use labview_interop::types::{ErrorClusterPtr, ToLvError};
@@ -17,9 +18,26 @@ impl ToLvError for ErrorText {
 
 #[cfg(target_pointer_width = "64")]
 #[no_mangle]
-pub extern "C" fn set_error_cluster(error_cluster: ErrorClusterPtr) -> LVStatusCode {
+pub extern "C" fn set_error_cluster(mut error_cluster: ErrorClusterPtr) -> LVStatusCode {
     let error = ErrorText("This is a test");
-    error.write_error(error_cluster).into()
+    error.write_error(&mut error_cluster).into()
+}
+
+/// Check scenarios for the error cluster function wrapping.
+#[cfg(target_pointer_width = "64")]
+#[no_mangle]
+pub extern "C" fn wrap_function(
+    mut error_cluster: ErrorClusterPtr,
+    mut text: LStrHandle,
+    inner_error: i16,
+) -> i32 {
+    error_cluster.wrap_function(42, || -> Result<i32, LVInteropError> {
+        text.set_str("Hello World")?;
+        if inner_error != 0 {
+            return Err(LVInteropError::from(LVStatusCode::from(1)));
+        }
+        Ok(0)
+    })
 }
 
 #[no_mangle]

labview-test-project/Error Tests/Error Tests.lvclass

@@ -78,4 +78,31 @@
 		<Property Name="NI.ClassItem.Priority" Type="Int">1</Property>
 		<Property Name="NI.ClassItem.State" Type="Int">1342710288</Property>
 	</Item>
+	<Item Name="test Error Wrapping - No Execute On Error In.vi" Type="VI" URL="../test Error Wrapping - No Execute On Error In.vi">
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+		<Property Name="NI.ClassItem.ExecutionSystem" Type="Int">-1</Property>
+		<Property Name="NI.ClassItem.Flags" Type="Int">16777216</Property>
+		<Property Name="NI.ClassItem.IsStaticMethod" Type="Bool">true</Property>
+		<Property Name="NI.ClassItem.MethodScope" Type="UInt">1</Property>
+		<Property Name="NI.ClassItem.Priority" Type="Int">1</Property>
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+	</Item>
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+	</Item>
 </LVClass>

labview-test-project/rust-interop-test.lvlps

@@ -1,2 +1,2 @@
 [ProjectWindow_Data]
-ProjectExplorer.ClassicPosition[String] = "37,769,915,1535"
+ProjectExplorer.ClassicPosition[String] = "33,769,911,1535"