Add build.rs generation back (wayland-* is absurd to compile w/o it)

src/bazel.rs

@@ -19,6 +19,7 @@ impl BazelRenderer {
     // Configure tera with a bogus template dir: We don't want any runtime template support
     let mut renderer = Tera::new("src/not/a/dir/*").unwrap();
     renderer.add_raw_templates(vec![
+      ("templates/partials/build_script.template", include_str!("templates/partials/build_script.template")),
       ("templates/partials/rust_binary.template", include_str!("templates/partials/rust_binary.template")),
       ("templates/partials/rust_library.template", include_str!("templates/partials/rust_library.template")),
       ("templates/workspace.BUILD.template", include_str!("templates/workspace.BUILD.template")),

src/planning.rs

@@ -97,15 +97,24 @@ impl <'a>  BuildPlanner<'a> {
 
           let mut targets = try!(identify_targets(&full_name, &package));
           targets.sort();
-          let build_script_target = targets.iter().find(|t| t.kind.deref() == "custom-build").cloned();
-          let targets_sans_build_script =
-            targets.into_iter().filter(|t| t.kind.deref() != "custom-build").collect::<Vec<_>>();
 
           let possible_crate_settings =
             self.settings.crates
               .get(id.name())
               .and_then(|c| c.get(&id.version().to_string()));
 
+          let should_gen_buildrs =
+            possible_crate_settings.map(|s| s.gen_buildrs.clone()).unwrap_or(false);
+          let build_script_target = if should_gen_buildrs {
+            targets.iter().find(|t| t.kind.deref() == "custom-build").cloned()
+          } else {
+            None
+          };
+
+          let targets_sans_build_script =
+            targets.into_iter().filter(|t| t.kind.deref() != "custom-build").collect::<Vec<_>>();
+
+
           let additional_deps =
             possible_crate_settings.map(|s| s.additional_deps.clone()).unwrap_or(Vec::new());
 

src/settings.rs

@@ -30,4 +30,11 @@ pub struct CrateSettings {
   /** Flags to be added to the crate compilation process, in the form "--flag". */
   #[serde(default)]
   pub additional_flags: Vec<String>,
+
+  #[serde(default = "default_gen_buildrs")]
+  pub gen_buildrs: bool,
+}
+
+fn default_gen_buildrs() -> bool {
+  false
 }

src/templates/crate.BUILD.template

@@ -13,6 +13,9 @@ load(
     "rust_bench_test",
 )
 {% set crate_name_sanitized = crate.pkg_name | replace(from="-", to="_") %}
+{% if crate.build_script_target %}
+{% include "templates/partials/build_script.template" %}
+{% endif %}
 {% for target in crate.targets %}
 {% if target.kind == "lib" %}
 {% include "templates/partials/rust_library.template" %}

src/templates/partials/build_script.template

@@ -0,0 +1,50 @@
+rust_binary(
+    name = "{{ crate_name_sanitized }}_build_script",
+    srcs = glob(["**/*.rs"]),
+    {% if crate.build_script_target.path %}
+    crate_root = "{{ crate.build_script_target.path }}",
+    {% else %}
+    crate_root = "build.rs",
+    {% endif %}
+    data = glob([
+      "*"
+    ]),
+    {% if crate.dependencies | length > 0 or crate.build_dependencies | length > 0 %}
+    deps = [
+      {% for dependency in crate.build_dependencies %}
+        "{{path_prefix}}/vendor/{{dependency.name}}-{{dependency.version}}:{{dependency.name | replace(from="-", to="_") }}",
+      {% endfor %}
+    ],
+    {% endif %}
+    rustc_flags = [
+        "--cap-lints allow",
+        "--target={{crate.platform_triple}}",
+    ],
+    {% if crate.features | length > 0 %}
+    crate_features = [
+      {% for feature in crate.features %}
+      "{{feature}}",
+      {% endfor %}
+    ],
+    {% endif %}
+    visibility = ["//visibility:private"],
+)
+
+genrule(
+    name = "{{ crate_name_sanitized  }}_build_script_executor",
+    srcs = glob(["*", "**/*.rs"]),
+    outs = ["{{ crate_name_sanitized  }}_out_dir_outputs.tar.gz"],
+    tools = [":{{ crate_name_sanitized  }}_build_script"],
+    local = 1,
+    cmd = "mkdir {{ crate_name_sanitized}}_out_dir_outputs/;"
+        + " (export CARGO_MANIFEST_DIR=\"$$PWD/{{ path_prefix | replace(from="//", to="") }}/vendor/{{ crate.pkg_name }}-{{ crate.pkg_version }}\";"
+        + " export TARGET='{{ crate.platform_triple }}';"
+        + " export RUST_BACKTRACE=1;"
+        {% for feature in crate.features %}
+        + " export CARGO_FEATURE_{{ feature | upper | replace(from="-", to="_") }}=1;"
+        {% endfor %}
+        + " export OUT_DIR=$$PWD/{{ crate_name_sanitized }}_out_dir_outputs;"
+        + " export BINARY_PATH=\"$$PWD/$(location :{{ crate_name_sanitized }}_build_script)\";"
+        + " export OUT_TAR=$$PWD/$@;"
+        + " cd $$(dirname $(location :Cargo.toml)) && $$BINARY_PATH && tar -czf $$OUT_TAR -C $$OUT_DIR .)"
+)

src/templates/partials/rust_binary.template

@@ -18,6 +18,9 @@ rust_binary(
         "{{flag}}",
         {% endfor %}
     ],
+    {% if crate.build_script_target %}
+    out_dir_tar = ":{{ crate.pkg_name | replace(from="-", to="_")}}_build_script_executor",
+    {% endif %}
     crate_features = [
         {% for feature in crate.features %}
         "{{feature}}",

src/templates/partials/rust_library.template

@@ -25,6 +25,9 @@ rust_library(
         "{{flag}}",
         {% endfor %}
     ],
+    {% if crate.build_script_target %}
+    out_dir_tar = ":{{ crate.pkg_name | replace(from="-", to="_")}}_build_script_executor",
+    {% endif %}
     crate_features = [
         {% for feature in crate.features %}
         "{{feature}}",