Squashed 'third_party/autocxx/' content from commit 629e8fa53

git-subtree-dir: third_party/autocxx
git-subtree-split: 629e8fa531a633164c0b52e2a3cab536d4cd0849
Signed-off-by: Brian Silverman <bsilver16384@gmail.com>
Change-Id: I62a03b0049f49adf029e0204639cdb5468dde1a1
diff --git a/engine/src/conversion/parse/parse_bindgen.rs b/engine/src/conversion/parse/parse_bindgen.rs
new file mode 100644
index 0000000..0818aa5
--- /dev/null
+++ b/engine/src/conversion/parse/parse_bindgen.rs
@@ -0,0 +1,388 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use indexmap::map::IndexMap as HashMap;
+use indexmap::set::IndexSet as HashSet;
+
+use crate::{
+    conversion::{
+        api::{Api, ApiName, NullPhase, StructDetails, SubclassName, TypedefKind, UnanalyzedApi},
+        apivec::ApiVec,
+        ConvertError,
+    },
+    types::Namespace,
+    types::QualifiedName,
+};
+use crate::{
+    conversion::{
+        convert_error::{ConvertErrorWithContext, ErrorContext},
+        error_reporter::report_any_error,
+    },
+    types::validate_ident_ok_for_cxx,
+};
+use autocxx_parser::{IncludeCppConfig, RustPath};
+use syn::{parse_quote, Fields, Ident, Item, Type, TypePath, UseTree};
+
+use super::{
+    super::utilities::generate_utilities, bindgen_semantic_attributes::BindgenSemanticAttributes,
+};
+
+use super::parse_foreign_mod::ParseForeignMod;
+
+/// Parses a bindgen mod in order to understand the APIs within it.
+pub(crate) struct ParseBindgen<'a> {
+    config: &'a IncludeCppConfig,
+    apis: ApiVec<NullPhase>,
+}
+
+fn api_name(ns: &Namespace, id: Ident, attrs: &BindgenSemanticAttributes) -> ApiName {
+    ApiName::new_with_cpp_name(ns, id, attrs.get_original_name())
+}
+
+pub(crate) fn api_name_qualified(
+    ns: &Namespace,
+    id: Ident,
+    attrs: &BindgenSemanticAttributes,
+) -> Result<ApiName, ConvertErrorWithContext> {
+    match validate_ident_ok_for_cxx(&id.to_string()) {
+        Err(e) => {
+            let ctx = ErrorContext::new_for_item(id);
+            Err(ConvertErrorWithContext(e, Some(ctx)))
+        }
+        Ok(..) => Ok(api_name(ns, id, attrs)),
+    }
+}
+
+impl<'a> ParseBindgen<'a> {
+    pub(crate) fn new(config: &'a IncludeCppConfig) -> Self {
+        ParseBindgen {
+            config,
+            apis: ApiVec::new(),
+        }
+    }
+
+    /// Parses items found in the `bindgen` output and returns a set of
+    /// `Api`s together with some other data.
+    pub(crate) fn parse_items(
+        mut self,
+        items: Vec<Item>,
+    ) -> Result<ApiVec<NullPhase>, ConvertError> {
+        let items = Self::find_items_in_root(items)?;
+        if !self.config.exclude_utilities() {
+            generate_utilities(&mut self.apis, self.config);
+        }
+        self.add_apis_from_config();
+        let root_ns = Namespace::new();
+        self.parse_mod_items(items, root_ns);
+        self.confirm_all_generate_directives_obeyed()?;
+        self.replace_extern_cpp_types();
+        Ok(self.apis)
+    }
+
+    /// Some API items are not populated from bindgen output, but instead
+    /// directly from items in the config.
+    fn add_apis_from_config(&mut self) {
+        self.apis
+            .extend(self.config.subclasses.iter().map(|sc| Api::Subclass {
+                name: SubclassName::new(sc.subclass.clone()),
+                superclass: QualifiedName::new_from_cpp_name(&sc.superclass),
+            }));
+        self.apis
+            .extend(self.config.extern_rust_funs.iter().map(|fun| {
+                let id = fun.sig.ident.clone();
+                Api::RustFn {
+                    name: ApiName::new_in_root_namespace(id),
+                    details: fun.clone(),
+                    receiver: fun.receiver.as_ref().map(|receiver_id| {
+                        QualifiedName::new(&Namespace::new(), receiver_id.clone())
+                    }),
+                }
+            }));
+        let unique_rust_types: HashSet<&RustPath> = self.config.rust_types.iter().collect();
+        self.apis.extend(unique_rust_types.into_iter().map(|path| {
+            let id = path.get_final_ident();
+            Api::RustType {
+                name: ApiName::new_in_root_namespace(id.clone()),
+                path: path.clone(),
+            }
+        }));
+        self.apis.extend(
+            self.config
+                .concretes
+                .0
+                .iter()
+                .map(|(cpp_definition, rust_id)| {
+                    let name = ApiName::new_in_root_namespace(rust_id.clone());
+                    Api::ConcreteType {
+                        name,
+                        cpp_definition: cpp_definition.clone(),
+                        rs_definition: None,
+                    }
+                }),
+        );
+    }
+
+    /// We do this last, _after_ we've parsed all the APIs, because we might want to actually
+    /// replace some of the existing APIs (structs/enums/etc.) with replacements.
+    fn replace_extern_cpp_types(&mut self) {
+        let pod_requests: HashSet<_> = self.config.get_pod_requests().iter().collect();
+        let replacements: HashMap<_, _> = self
+            .config
+            .externs
+            .0
+            .iter()
+            .map(|(cpp_definition, details)| {
+                let qn = QualifiedName::new_from_cpp_name(cpp_definition);
+                let pod = pod_requests.contains(&qn.to_cpp_name());
+                (
+                    qn.clone(),
+                    Api::ExternCppType {
+                        name: ApiName::new_from_qualified_name(qn),
+                        details: details.clone(),
+                        pod,
+                    },
+                )
+            })
+            .collect();
+        self.apis
+            .retain(|api| !replacements.contains_key(api.name()));
+        self.apis.extend(replacements.into_iter().map(|(_, v)| v));
+    }
+
+    fn find_items_in_root(items: Vec<Item>) -> Result<Vec<Item>, ConvertError> {
+        for item in items {
+            match item {
+                Item::Mod(root_mod) => {
+                    // With namespaces enabled, bindgen always puts everything
+                    // in a mod called 'root'. We don't want to pass that
+                    // onto cxx, so jump right into it.
+                    assert!(root_mod.ident == "root");
+                    if let Some((_, items)) = root_mod.content {
+                        return Ok(items);
+                    }
+                }
+                _ => return Err(ConvertError::UnexpectedOuterItem),
+            }
+        }
+        Ok(Vec::new())
+    }
+
+    /// Interpret the bindgen-generated .rs for a particular
+    /// mod, which corresponds to a C++ namespace.
+    fn parse_mod_items(&mut self, items: Vec<Item>, ns: Namespace) {
+        // This object maintains some state specific to this namespace, i.e.
+        // this particular mod.
+        let mut mod_converter = ParseForeignMod::new(ns.clone());
+        let mut more_apis = ApiVec::new();
+        for item in items {
+            report_any_error(&ns, &mut more_apis, || {
+                self.parse_item(item, &mut mod_converter, &ns)
+            });
+        }
+        self.apis.append(&mut more_apis);
+        mod_converter.finished(&mut self.apis);
+    }
+
+    fn parse_item(
+        &mut self,
+        item: Item,
+        mod_converter: &mut ParseForeignMod,
+        ns: &Namespace,
+    ) -> Result<(), ConvertErrorWithContext> {
+        match item {
+            Item::ForeignMod(fm) => {
+                mod_converter.convert_foreign_mod_items(fm.items);
+                Ok(())
+            }
+            Item::Struct(s) => {
+                if s.ident.to_string().ends_with("__bindgen_vtable") {
+                    return Ok(());
+                }
+                let annotations = BindgenSemanticAttributes::new(&s.attrs);
+                // cxx::bridge can't cope with type aliases to generic
+                // types at the moment.
+                let name = api_name_qualified(ns, s.ident.clone(), &annotations)?;
+                let err = annotations.check_for_fatal_attrs(&s.ident).err();
+                let api = if ns.is_empty() && self.config.is_rust_type(&s.ident) {
+                    None
+                } else if Self::spot_forward_declaration(&s.fields)
+                    || (Self::spot_zero_length_struct(&s.fields) && err.is_some())
+                {
+                    // Forward declarations are recorded especially because we can't
+                    // store them in UniquePtr or similar.
+                    // Templated forward declarations don't appear with an _unused field (which is what
+                    // we spot in the previous clause) but instead with an _address field.
+                    // So, solely in the case where we're storing up an error about such
+                    // a templated type, we'll also treat such cases as forward declarations.
+                    Some(UnanalyzedApi::ForwardDeclaration { name, err })
+                } else {
+                    let has_rvalue_reference_fields = s.fields.iter().any(|f| {
+                        BindgenSemanticAttributes::new(&f.attrs).has_attr("rvalue_reference")
+                    });
+                    Some(UnanalyzedApi::Struct {
+                        name,
+                        details: Box::new(StructDetails {
+                            vis: annotations.get_cpp_visibility(),
+                            layout: annotations.get_layout(),
+                            item: s,
+                            has_rvalue_reference_fields,
+                        }),
+                        analysis: (),
+                    })
+                };
+                if let Some(api) = api {
+                    if !self.config.is_on_blocklist(&api.name().to_cpp_name()) {
+                        self.apis.push(api);
+                    }
+                }
+                Ok(())
+            }
+            Item::Enum(e) => {
+                let annotations = BindgenSemanticAttributes::new(&e.attrs);
+                let api = UnanalyzedApi::Enum {
+                    name: api_name_qualified(ns, e.ident.clone(), &annotations)?,
+                    item: e,
+                };
+                if !self.config.is_on_blocklist(&api.name().to_cpp_name()) {
+                    self.apis.push(api);
+                }
+                Ok(())
+            }
+            Item::Impl(imp) => {
+                // We *mostly* ignore all impl blocks generated by bindgen.
+                // Methods also appear in 'extern "C"' blocks which
+                // we will convert instead. At that time we'll also construct
+                // synthetic impl blocks.
+                // We do however record which methods were spotted, since
+                // we have no other way of working out which functions are
+                // static methods vs plain functions.
+                mod_converter.convert_impl_items(imp);
+                Ok(())
+            }
+            Item::Mod(itm) => {
+                if let Some((_, items)) = itm.content {
+                    let new_ns = ns.push(itm.ident.to_string());
+                    self.parse_mod_items(items, new_ns);
+                }
+                Ok(())
+            }
+            Item::Use(use_item) => {
+                let mut segs = Vec::new();
+                let mut tree = &use_item.tree;
+                loop {
+                    match tree {
+                        UseTree::Path(up) => {
+                            segs.push(up.ident.clone());
+                            tree = &up.tree;
+                        }
+                        UseTree::Name(un) if un.ident == "root" => break, // we do not add this to any API since we generate equivalent
+                        // use statements in our codegen phase.
+                        UseTree::Rename(urn) => {
+                            let old_id = &urn.ident;
+                            let new_id = &urn.rename;
+                            let new_tyname = QualifiedName::new(ns, new_id.clone());
+                            assert!(segs.remove(0) == "self", "Path didn't start with self");
+                            assert!(
+                                segs.remove(0) == "super",
+                                "Path didn't start with self::super"
+                            );
+                            // This is similar to the path encountered within 'tree'
+                            // but without the self::super prefix which is unhelpful
+                            // in our output mod, because we prefer relative paths
+                            // (we're nested in another mod)
+                            let old_path: TypePath = parse_quote! {
+                                #(#segs)::* :: #old_id
+                            };
+                            let old_tyname = QualifiedName::from_type_path(&old_path);
+                            if new_tyname == old_tyname {
+                                return Err(ConvertErrorWithContext(
+                                    ConvertError::InfinitelyRecursiveTypedef(new_tyname),
+                                    Some(ErrorContext::new_for_item(new_id.clone())),
+                                ));
+                            }
+                            let annotations = BindgenSemanticAttributes::new(&use_item.attrs);
+                            self.apis.push(UnanalyzedApi::Typedef {
+                                name: api_name(ns, new_id.clone(), &annotations),
+                                item: TypedefKind::Use(
+                                    parse_quote! {
+                                        pub use #old_path as #new_id;
+                                    },
+                                    Box::new(Type::Path(old_path)),
+                                ),
+                                old_tyname: Some(old_tyname),
+                                analysis: (),
+                            });
+                            break;
+                        }
+                        _ => {
+                            return Err(ConvertErrorWithContext(
+                                ConvertError::UnexpectedUseStatement(
+                                    segs.into_iter().last().map(|i| i.to_string()),
+                                ),
+                                None,
+                            ))
+                        }
+                    }
+                }
+                Ok(())
+            }
+            Item::Const(const_item) => {
+                let annotations = BindgenSemanticAttributes::new(&const_item.attrs);
+                self.apis.push(UnanalyzedApi::Const {
+                    name: api_name(ns, const_item.ident.clone(), &annotations),
+                    const_item,
+                });
+                Ok(())
+            }
+            Item::Type(ity) => {
+                let annotations = BindgenSemanticAttributes::new(&ity.attrs);
+                // It's known that sometimes bindgen will give us duplicate typedefs with the
+                // same name - see test_issue_264.
+                self.apis.push(UnanalyzedApi::Typedef {
+                    name: api_name(ns, ity.ident.clone(), &annotations),
+                    item: TypedefKind::Type(ity),
+                    old_tyname: None,
+                    analysis: (),
+                });
+                Ok(())
+            }
+            _ => Err(ConvertErrorWithContext(
+                ConvertError::UnexpectedItemInMod,
+                None,
+            )),
+        }
+    }
+
+    fn spot_forward_declaration(s: &Fields) -> bool {
+        Self::spot_field(s, "_unused")
+    }
+
+    fn spot_zero_length_struct(s: &Fields) -> bool {
+        Self::spot_field(s, "_address")
+    }
+
+    fn spot_field(s: &Fields, desired_id: &str) -> bool {
+        s.iter()
+            .filter_map(|f| f.ident.as_ref())
+            .any(|id| id == desired_id)
+    }
+
+    fn confirm_all_generate_directives_obeyed(&self) -> Result<(), ConvertError> {
+        let api_names: HashSet<_> = self
+            .apis
+            .iter()
+            .map(|api| api.name().to_cpp_name())
+            .collect();
+        for generate_directive in self.config.must_generate_list() {
+            if !api_names.contains(&generate_directive) {
+                return Err(ConvertError::DidNotGenerateAnything(generate_directive));
+            }
+        }
+        Ok(())
+    }
+}