refactor(toml): Move target build.rs logic next to use

Author: epage

src/cargo/util/toml/mod.rs

@@ -1310,30 +1310,6 @@ impl schema::TomlManifest {
         }
         Ok(patch)
     }
-
-    /// Returns the path to the build script if one exists for this crate.
-    fn maybe_custom_build(
-        &self,
-        build: &Option<schema::StringOrBool>,
-        package_root: &Path,
-    ) -> Option<PathBuf> {
-        let build_rs = package_root.join("build.rs");
-        match *build {
-            // Explicitly no build script.
-            Some(schema::StringOrBool::Bool(false)) => None,
-            Some(schema::StringOrBool::Bool(true)) => Some(build_rs),
-            Some(schema::StringOrBool::String(ref s)) => Some(PathBuf::from(s)),
-            None => {
-                // If there is a `build.rs` file next to the `Cargo.toml`, assume it is
-                // a build script.
-                if build_rs.is_file() {
-                    Some(build_rs)
-                } else {
-                    None
-                }
-            }
-        }
-    }
 }
 
 struct Context<'a, 'b> {

src/cargo/util/toml/targets.rs

@@ -105,7 +105,7 @@ pub(super) fn targets(
     )?);
 
     // processing the custom build script
-    if let Some(custom_build) = manifest.maybe_custom_build(custom_build, package_root) {
+    if let Some(custom_build) = maybe_custom_build(custom_build, package_root) {
         if metabuild.is_some() {
             anyhow::bail!("cannot specify both `metabuild` and `build`");
         }
@@ -964,3 +964,23 @@ Cargo doesn't know which to use because multiple target files found at `{}` and
         (None, Some(_)) => unreachable!(),
     }
 }
+
+/// Returns the path to the build script if one exists for this crate.
+fn maybe_custom_build(build: &Option<StringOrBool>, package_root: &Path) -> Option<PathBuf> {
+    let build_rs = package_root.join("build.rs");
+    match *build {
+        // Explicitly no build script.
+        Some(StringOrBool::Bool(false)) => None,
+        Some(StringOrBool::Bool(true)) => Some(build_rs),
+        Some(StringOrBool::String(ref s)) => Some(PathBuf::from(s)),
+        None => {
+            // If there is a `build.rs` file next to the `Cargo.toml`, assume it is
+            // a build script.
+            if build_rs.is_file() {
+                Some(build_rs)
+            } else {
+                None
+            }
+        }
+    }
+}