Merge pull request #323 from armansito/shaders-fixes-for-bazel

[shaders] Shader path look up fixes for hermetic builds

crates/shaders/build.rs

@@ -8,14 +8,26 @@ mod types;
 
 use std::env;
 use std::fmt::Write;
-use std::path::Path;
+use std::path::{Path, PathBuf};
 
 use compile::ShaderInfo;
 
 fn main() {
     let out_dir = env::var_os("OUT_DIR").unwrap();
     let dest_path = Path::new(&out_dir).join("shaders.rs");
-    let mut shaders = compile::ShaderInfo::from_dir("../../shader");
+
+    // The shaders are defined under the workspace root and not in this crate so we need to locate
+    // them somehow. Cargo doesn't define an environment variable that points at the root workspace
+    // directory. In hermetic build environments that don't support relative paths (such as Bazel)
+    // we support supplying a `WORKSPACE_MANIFEST_FILE` that is expected to be an absolute path to
+    // the Cargo.toml file at the workspace root. If that's not present, we use a relative path.
+    let workspace_dir = env::var("WORKSPACE_MANIFEST_FILE")
+        .ok()
+        .and_then(|p| Path::new(&p).parent().map(|p| p.to_owned()))
+        .unwrap_or(PathBuf::from("../../"));
+    let shader_dir = Path::new(&workspace_dir).join("shader");
+    let mut shaders = compile::ShaderInfo::from_dir(&shader_dir);
+
     // Drop the HashMap and sort by name so that we get deterministic order.
     let mut shaders = shaders.drain().collect::<Vec<_>>();
     shaders.sort_by(|x, y| x.0.cmp(&y.0));

crates/shaders/src/compile/mod.rs

@@ -166,9 +166,11 @@ impl ShaderInfo {
         for entry in shader_dir
             .read_dir()
             .expect("Can read shader import directory")
+            .filter_map(move |e| {
+                e.ok()
+                    .filter(|e| e.path().extension().map(|e| e == "wgsl").unwrap_or(false))
+            })
         {
-            let entry = entry.expect("Can continue reading shader import directory");
-            if entry.file_type().unwrap().is_file() {
             let file_name = entry.file_name();
             if let Some(name) = file_name.to_str() {
                 let suffix = ".wgsl";
@@ -191,7 +193,6 @@ impl ShaderInfo {
                 }
             }
         }
-        }
         info
     }
 }

crates/shaders/src/compile/preprocess.rs

@@ -14,9 +14,11 @@ pub fn get_imports(shader_dir: &Path) -> HashMap<String, String> {
     for entry in imports_dir
         .read_dir()
         .expect("Can read shader import directory")
+        .filter_map(move |e| {
+            e.ok()
+                .filter(|e| e.path().extension().map(|e| e == "wgsl").unwrap_or(false))
+        })
     {
-        let entry = entry.expect("Can continue reading shader import directory");
-        if entry.file_type().unwrap().is_file() {
         let file_name = entry.file_name();
         if let Some(name) = file_name.to_str() {
             let suffix = ".wgsl";
@@ -27,7 +29,6 @@ pub fn get_imports(shader_dir: &Path) -> HashMap<String, String> {
             }
         }
     }
-    }
     imports
 }