API tweaks surrounding generic types.

This commit allows multiple generic types on public-facing new methods.
A good example of why this is useful is for the correlator context; when
using a &Path for the metafits, gpubox files must then be a slice of
&Path, which is an unusual collection to have. This commit makes it
possible to use a &Path for the metafits and &[PathBuf] for the
gpuboxes.

Also split the new method logic into new_inner functions. These should
remain private, and this is done to help keep compilation complexity
low. See "Compilation Model: Monomorphization" from this site for more
info: https://matklad.github.io/2021/09/04/fast-rust-builds.html

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 Changes in each release are listed below.
 
+## Unreleased
+* API tweaks surrounding generic types.
+  * Things should be slightly more flexible than before.
+
 ## 0.14.0 13-Apr-2022 (Pre-release)
 * Specify minimum-required dependency versions.
 * Clean up fits long-string functions.

src/correlator_context/mod.rs

@@ -7,6 +7,7 @@ The main interface to MWA data.
  */
 use std::collections::BTreeMap;
 use std::fmt;
+use std::path::Path;
 
 use crate::coarse_channel::*;
 use crate::convert::*;
@@ -132,9 +133,16 @@ impl CorrelatorContext {
     /// * Result containing a populated CorrelatorContext object if Ok.
     ///
     ///
-    pub fn new<T: AsRef<std::path::Path>>(
-        metafits_filename: T,
-        gpubox_filenames: &[T],
+    pub fn new<P: AsRef<Path>, P2: AsRef<Path>>(
+        metafits_filename: P,
+        gpubox_filenames: &[P2],
+    ) -> Result<Self, MwalibError> {
+        Self::new_inner(metafits_filename.as_ref(), gpubox_filenames)
+    }
+
+    fn new_inner<P: AsRef<Path>>(
+        metafits_filename: &Path,
+        gpubox_filenames: &[P],
     ) -> Result<Self, MwalibError> {
         let mut metafits_context = MetafitsContext::new_internal(metafits_filename)?;
 

src/correlator_context/test.rs

@@ -5,9 +5,9 @@
 /*!
 Unit tests for correlator context
 */
-#[cfg(test)]
 use super::*;
 use float_cmp::*;
+use std::path::PathBuf;
 
 #[test]
 fn test_context_new_with_only_non000_batch() {
@@ -63,7 +63,7 @@ fn test_context_new_with_000_and_001_batch() {
 #[test]
 fn test_context_new_missing_gpubox_files() {
     let metafits_filename = "test_files/1101503312_1_timestep/1101503312.metafits";
-    let gpuboxfiles = Vec::new();
+    let gpuboxfiles: Vec<PathBuf> = Vec::new();
 
     // No gpubox files provided
     let context = CorrelatorContext::new(metafits_filename, &gpuboxfiles);

src/metafits_context/mod.rs

@@ -5,9 +5,11 @@
 /*!
 The main interface to MWA data.
  */
+use std::fmt;
+use std::path::Path;
+
 use chrono::{DateTime, Duration, FixedOffset};
 use num_derive::FromPrimitive;
-use std::fmt;
 
 use crate::antenna::*;
 use crate::baseline::*;
@@ -467,10 +469,14 @@ impl MetafitsContext {
     /// * Result containing a populated MetafitsContext object if Ok.
     ///
     ///
-    pub fn new<T: AsRef<std::path::Path>>(
-        metafits: T,
+    pub fn new<P: AsRef<Path>>(
+        metafits: P,
         mwa_version: Option<MWAVersion>,
     ) -> Result<Self, MwalibError> {
+        Self::new_inner(metafits.as_ref(), mwa_version)
+    }
+
+    fn new_inner(metafits: &Path, mwa_version: Option<MWAVersion>) -> Result<Self, MwalibError> {
         // Call the internal new metafits method
         let mut new_context = MetafitsContext::new_internal(metafits)?;
 

src/voltage_context/mod.rs

@@ -15,6 +15,7 @@ use std::fmt;
 use std::fs::File;
 use std::io::BufReader;
 use std::io::{Read, Seek, SeekFrom};
+use std::path::Path;
 
 #[cfg(test)]
 pub(crate) mod test; // It's pub crate because I reuse some test code in the ffi tests.
@@ -153,9 +154,16 @@ impl VoltageContext {
     /// * Result containing a populated VoltageContext object if Ok.
     ///
     ///
-    pub fn new<T: AsRef<std::path::Path>>(
-        metafits_filename: T,
-        voltage_filenames: &[T],
+    pub fn new<P: AsRef<Path>, P2: AsRef<Path>>(
+        metafits_filename: P,
+        voltage_filenames: &[P2],
+    ) -> Result<Self, MwalibError> {
+        Self::new_inner(metafits_filename.as_ref(), voltage_filenames)
+    }
+
+    fn new_inner<P: AsRef<Path>>(
+        metafits_filename: &Path,
+        voltage_filenames: &[P],
     ) -> Result<Self, MwalibError> {
         let mut metafits_context = MetafitsContext::new_internal(metafits_filename)?;
 

src/voltage_context/test.rs

@@ -10,6 +10,7 @@ use super::*;
 use float_cmp::*;
 use std::fs::File;
 use std::io::{Error, Write};
+use std::path::PathBuf;
 use std::sync::Once;
 
 // Define two static "once" variables to control creation of VCS test data (so it only happens once, the first time it's needed)
@@ -308,7 +309,7 @@ pub(crate) fn get_test_voltage_context(mwa_version: MWAVersion) -> VoltageContex
 #[test]
 fn test_context_new_missing_voltage_files() {
     let metafits_filename = "test_files/1101503312_1_timestep/1101503312.metafits";
-    let voltagefiles = Vec::new();
+    let voltagefiles: Vec<PathBuf> = Vec::new();
 
     // No gpubox files provided
     let context = VoltageContext::new(&metafits_filename, &voltagefiles);