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)
+    }
+}