Vendor things

third-party/vendor/bindgen/codegen/postprocessing/merge_extern_blocks.rs

@@ -0,0 +1,66 @@
+use syn::{
+    visit_mut::{visit_item_mod_mut, VisitMut},
+    Item, ItemForeignMod, ItemMod,
+};
+
+pub(super) fn merge_extern_blocks(item_mod: &mut ItemMod) {
+    Visitor.visit_item_mod_mut(item_mod)
+}
+
+struct Visitor;
+
+impl VisitMut for Visitor {
+    fn visit_item_mod_mut(&mut self, item_mod: &mut ItemMod) {
+        if let Some((_, ref mut items)) = item_mod.content {
+            // Keep all the extern blocks in a different `Vec` for faster search.
+            let mut extern_blocks = Vec::<ItemForeignMod>::new();
+
+            for item in std::mem::take(items) {
+                if let Item::ForeignMod(ItemForeignMod {
+                    attrs,
+                    abi,
+                    brace_token,
+                    items: extern_block_items,
+                }) = item
+                {
+                    let mut exists = false;
+                    for extern_block in &mut extern_blocks {
+                        // Check if there is a extern block with the same ABI and
+                        // attributes.
+                        if extern_block.attrs == attrs &&
+                            extern_block.abi == abi
+                        {
+                            // Merge the items of the two blocks.
+                            extern_block
+                                .items
+                                .extend_from_slice(&extern_block_items);
+                            exists = true;
+                            break;
+                        }
+                    }
+                    // If no existing extern block had the same ABI and attributes, store
+                    // it.
+                    if !exists {
+                        extern_blocks.push(ItemForeignMod {
+                            attrs,
+                            abi,
+                            brace_token,
+                            items: extern_block_items,
+                        });
+                    }
+                } else {
+                    // If the item is not an extern block, we don't have to do anything and just
+                    // push it back.
+                    items.push(item);
+                }
+            }
+
+            // Move all the extern blocks alongside the rest of the items.
+            for extern_block in extern_blocks {
+                items.push(Item::ForeignMod(extern_block));
+            }
+        }
+
+        visit_item_mod_mut(self, item_mod)
+    }
+}

third-party/vendor/bindgen/codegen/postprocessing/mod.rs

@@ -0,0 +1,66 @@
+use proc_macro2::TokenStream;
+use quote::ToTokens;
+use syn::{parse2, ItemMod};
+
+use crate::BindgenOptions;
+
+mod merge_extern_blocks;
+mod sort_semantically;
+
+use merge_extern_blocks::merge_extern_blocks;
+use sort_semantically::sort_semantically;
+
+struct PostProcessingPass {
+    should_run: fn(&BindgenOptions) -> bool,
+    run: fn(&mut ItemMod),
+}
+
+// TODO: This can be a const fn when mutable references are allowed in const
+// context.
+macro_rules! pass {
+    ($pass:ident) => {
+        PostProcessingPass {
+            should_run: |options| options.$pass,
+            run: |item_mod| $pass(item_mod),
+        }
+    };
+}
+
+const PASSES: &[PostProcessingPass] =
+    &[pass!(merge_extern_blocks), pass!(sort_semantically)];
+
+pub(crate) fn postprocessing(
+    items: Vec<TokenStream>,
+    options: &BindgenOptions,
+) -> TokenStream {
+    let require_syn = PASSES.iter().any(|pass| (pass.should_run)(options));
+    if !require_syn {
+        return items.into_iter().collect();
+    }
+    let module_wrapped_tokens =
+        quote!(mod wrapper_for_postprocessing_hack { #( #items )* });
+
+    // This syn business is a hack, for now. This means that we are re-parsing already
+    // generated code using `syn` (as opposed to `quote`) because `syn` provides us more
+    // control over the elements.
+    // One caveat is that some of the items coming from `quote`d output might have
+    // multiple items within them. Hence, we have to wrap the incoming in a `mod`.
+    // The `unwrap` here is deliberate because bindgen should generate valid rust items at all
+    // times.
+    let mut item_mod = parse2::<ItemMod>(module_wrapped_tokens).unwrap();
+
+    for pass in PASSES {
+        if (pass.should_run)(options) {
+            (pass.run)(&mut item_mod);
+        }
+    }
+
+    let synful_items = item_mod
+        .content
+        .map(|(_, items)| items)
+        .unwrap_or_default()
+        .into_iter()
+        .map(|item| item.into_token_stream());
+
+    quote! { #( #synful_items )* }
+}

third-party/vendor/bindgen/codegen/postprocessing/sort_semantically.rs

@@ -0,0 +1,38 @@
+use syn::{
+    visit_mut::{visit_item_mod_mut, VisitMut},
+    Item, ItemMod,
+};
+
+pub(super) fn sort_semantically(item_mod: &mut ItemMod) {
+    Visitor.visit_item_mod_mut(item_mod)
+}
+
+struct Visitor;
+
+impl VisitMut for Visitor {
+    fn visit_item_mod_mut(&mut self, item_mod: &mut ItemMod) {
+        if let Some((_, ref mut items)) = item_mod.content {
+            items.sort_by_key(|item| match item {
+                Item::Type(_) => 0,
+                Item::Struct(_) => 1,
+                Item::Const(_) => 2,
+                Item::Fn(_) => 3,
+                Item::Enum(_) => 4,
+                Item::Union(_) => 5,
+                Item::Static(_) => 6,
+                Item::Trait(_) => 7,
+                Item::TraitAlias(_) => 8,
+                Item::Impl(_) => 9,
+                Item::Mod(_) => 10,
+                Item::Use(_) => 11,
+                Item::Verbatim(_) => 12,
+                Item::ExternCrate(_) => 13,
+                Item::ForeignMod(_) => 14,
+                Item::Macro(_) => 15,
+                Item::Macro2(_) => 16,
+                _ => 18,
+            });
+        }
+        visit_item_mod_mut(self, item_mod)
+    }
+}