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use crate::ir::comp::{BitfieldUnit, CompKind, Field, FieldData, FieldMethods};
use crate::ir::context::BindgenContext;
use crate::ir::item::{HasTypeParamInArray, IsOpaque, Item, ItemCanonicalName};
use crate::ir::ty::{TypeKind, RUST_DERIVE_IN_ARRAY_LIMIT};
pub(crate) fn gen_debug_impl(
ctx: &BindgenContext,
fields: &[Field],
item: &Item,
kind: CompKind,
) -> proc_macro2::TokenStream {
let struct_name = item.canonical_name(ctx);
let mut format_string = format!("{} {{{{ ", struct_name);
let mut tokens = vec![];
if item.is_opaque(ctx, &()) {
format_string.push_str("opaque");
} else {
match kind {
CompKind::Union => {
format_string.push_str("union");
}
CompKind::Struct => {
let processed_fields = fields.iter().filter_map(|f| match f {
Field::DataMember(ref fd) => fd.impl_debug(ctx, ()),
Field::Bitfields(ref bu) => bu.impl_debug(ctx, ()),
});
for (i, (fstring, toks)) in processed_fields.enumerate() {
if i > 0 {
format_string.push_str(", ");
}
tokens.extend(toks);
format_string.push_str(&fstring);
}
}
}
}
format_string.push_str(" }}");
tokens.insert(0, quote! { #format_string });
let prefix = ctx.trait_prefix();
quote! {
fn fmt(&self, f: &mut ::#prefix::fmt::Formatter<'_>) -> ::#prefix ::fmt::Result {
write!(f, #( #tokens ),*)
}
}
}
/// A trait for the things which we can codegen tokens that contribute towards a
/// generated `impl Debug`.
pub(crate) trait ImplDebug<'a> {
/// Any extra parameter required by this a particular `ImplDebug` implementation.
type Extra;
/// Generate a format string snippet to be included in the larger `impl Debug`
/// format string, and the code to get the format string's interpolation values.
fn impl_debug(
&self,
ctx: &BindgenContext,
extra: Self::Extra,
) -> Option<(String, Vec<proc_macro2::TokenStream>)>;
}
impl<'a> ImplDebug<'a> for FieldData {
type Extra = ();
fn impl_debug(
&self,
ctx: &BindgenContext,
_: Self::Extra,
) -> Option<(String, Vec<proc_macro2::TokenStream>)> {
if let Some(name) = self.name() {
ctx.resolve_item(self.ty()).impl_debug(ctx, name)
} else {
None
}
}
}
impl<'a> ImplDebug<'a> for BitfieldUnit {
type Extra = ();
fn impl_debug(
&self,
ctx: &BindgenContext,
_: Self::Extra,
) -> Option<(String, Vec<proc_macro2::TokenStream>)> {
let mut format_string = String::new();
let mut tokens = vec![];
for (i, bitfield) in self.bitfields().iter().enumerate() {
if i > 0 {
format_string.push_str(", ");
}
if let Some(bitfield_name) = bitfield.name() {
format_string.push_str(&format!("{} : {{:?}}", bitfield_name));
let getter_name = bitfield.getter_name();
let name_ident = ctx.rust_ident_raw(getter_name);
tokens.push(quote! {
self.#name_ident ()
});
}
}
Some((format_string, tokens))
}
}
impl<'a> ImplDebug<'a> for Item {
type Extra = &'a str;
fn impl_debug(
&self,
ctx: &BindgenContext,
name: &str,
) -> Option<(String, Vec<proc_macro2::TokenStream>)> {
let name_ident = ctx.rust_ident(name);
// We don't know if blocklisted items `impl Debug` or not, so we can't
// add them to the format string we're building up.
if !ctx.allowlisted_items().contains(&self.id()) {
return None;
}
let ty = match self.as_type() {
Some(ty) => ty,
None => {
return None;
}
};
fn debug_print(
name: &str,
name_ident: proc_macro2::TokenStream,
) -> Option<(String, Vec<proc_macro2::TokenStream>)> {
Some((
format!("{}: {{:?}}", name),
vec![quote! {
self.#name_ident
}],
))
}
match *ty.kind() {
// Handle the simple cases.
TypeKind::Void |
TypeKind::NullPtr |
TypeKind::Int(..) |
TypeKind::Float(..) |
TypeKind::Complex(..) |
TypeKind::Function(..) |
TypeKind::Enum(..) |
TypeKind::Reference(..) |
TypeKind::UnresolvedTypeRef(..) |
TypeKind::ObjCInterface(..) |
TypeKind::ObjCId |
TypeKind::Comp(..) |
TypeKind::ObjCSel => debug_print(name, quote! { #name_ident }),
TypeKind::TemplateInstantiation(ref inst) => {
if inst.is_opaque(ctx, self) {
Some((format!("{}: opaque", name), vec![]))
} else {
debug_print(name, quote! { #name_ident })
}
}
// The generic is not required to implement Debug, so we can not debug print that type
TypeKind::TypeParam => {
Some((format!("{}: Non-debuggable generic", name), vec![]))
}
TypeKind::Array(_, len) => {
// Generics are not required to implement Debug
if self.has_type_param_in_array(ctx) {
Some((
format!("{}: Array with length {}", name, len),
vec![],
))
} else if len < RUST_DERIVE_IN_ARRAY_LIMIT ||
ctx.options().rust_features().larger_arrays
{
// The simple case
debug_print(name, quote! { #name_ident })
} else if ctx.options().use_core {
// There is no String in core; reducing field visibility to avoid breaking
// no_std setups.
Some((format!("{}: [...]", name), vec![]))
} else {
// Let's implement our own print function
Some((
format!("{}: [{{}}]", name),
vec![quote! {
self.#name_ident
.iter()
.enumerate()
.map(|(i, v)| format!("{}{:?}", if i > 0 { ", " } else { "" }, v))
.collect::<String>()
}],
))
}
}
TypeKind::Vector(_, len) => {
if ctx.options().use_core {
// There is no format! in core; reducing field visibility to avoid breaking
// no_std setups.
Some((format!("{}(...)", name), vec![]))
} else {
let self_ids = 0..len;
Some((
format!("{}({{}})", name),
vec![quote! {
#(format!("{:?}", self.#self_ids)),*
}],
))
}
}
TypeKind::ResolvedTypeRef(t) |
TypeKind::TemplateAlias(t, _) |
TypeKind::Alias(t) |
TypeKind::BlockPointer(t) => {
// We follow the aliases
ctx.resolve_item(t).impl_debug(ctx, name)
}
TypeKind::Pointer(inner) => {
let inner_type = ctx.resolve_type(inner).canonical_type(ctx);
match *inner_type.kind() {
TypeKind::Function(ref sig)
if !sig.function_pointers_can_derive() =>
{
Some((format!("{}: FunctionPointer", name), vec![]))
}
_ => debug_print(name, quote! { #name_ident }),
}
}
TypeKind::Opaque => None,
}
}
}