This allows creating any serializable data structure from QObject.
Co-authored-by: Marc-André Lureau <[email protected]>
Signed-off-by: Marc-André Lureau <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
---
docs/devel/rust.rst | 1 +
rust/util/meson.build | 1 +
rust/util/src/qobject/deserializer.rs | 373 ++++++++++++++++++++++++++
rust/util/src/qobject/error.rs | 8 +-
rust/util/src/qobject/mod.rs | 2 +
5 files changed, 384 insertions(+), 1 deletion(-)
create mode 100644 rust/util/src/qobject/deserializer.rs
diff --git a/docs/devel/rust.rst b/docs/devel/rust.rst
index 79c26d9d165..c7f3a496a25 100644
--- a/docs/devel/rust.rst
+++ b/docs/devel/rust.rst
@@ -162,6 +162,7 @@ module status
``util::error`` stable
``util::log`` proof of concept
``util::module`` complete
+``util::qobject`` stable
``util::timer`` stable
========================== ======================
diff --git a/rust/util/meson.build b/rust/util/meson.build
index 2b72af99dd5..45366d03786 100644
--- a/rust/util/meson.build
+++ b/rust/util/meson.build
@@ -39,6 +39,7 @@ _util_rs = static_library(
{'.': _util_bindings_inc_rs,
'qobject': [
'src/qobject/mod.rs',
+ 'src/qobject/deserializer.rs',
'src/qobject/deserialize.rs',
'src/qobject/error.rs',
'src/qobject/serializer.rs',
diff --git a/rust/util/src/qobject/deserializer.rs
b/rust/util/src/qobject/deserializer.rs
new file mode 100644
index 00000000000..a2fe417e72a
--- /dev/null
+++ b/rust/util/src/qobject/deserializer.rs
@@ -0,0 +1,373 @@
+//! `QObject` deserializer
+//!
+//! This module implements a [`Deserializer`](serde::de::Deserializer) that
+//! produces `QObject`s, allowing them to be turned into deserializable data
+//! structures (such as primitive data types, or structs that implement
+//! `Deserialize`).
+
+use std::ffi::CStr;
+
+use serde::de::{
+ self, value::StrDeserializer, DeserializeSeed, Expected, MapAccess,
SeqAccess, Unexpected,
+ Visitor,
+};
+
+use super::{
+ error::{Error, Result},
+ match_qobject, QObject,
+};
+use crate::bindings;
+
+impl QObject {
+ #[cold]
+ fn invalid_type<E>(&self, exp: &dyn Expected) -> E
+ where
+ E: serde::de::Error,
+ {
+ serde::de::Error::invalid_type(self.unexpected(), exp)
+ }
+
+ #[cold]
+ fn unexpected(&self) -> Unexpected<'_> {
+ match_qobject! { (self) =>
+ () => Unexpected::Unit,
+ bool(b) => Unexpected::Bool(b),
+ i64(n) => Unexpected::Signed(n),
+ u64(n) => Unexpected::Unsigned(n),
+ f64(n) => Unexpected::Float(n),
+ CStr(s) => s.to_str().map_or_else(
+ |_| Unexpected::Other("string with invalid UTF-8"),
+ Unexpected::Str),
+ QList(_) => Unexpected::Seq,
+ QDict(_) => Unexpected::Map,
+ }
+ }
+}
+
+fn visit_qlist_ref<'de, V>(qlist: &'de bindings::QList, visitor: V) ->
Result<V::Value>
+where
+ V: Visitor<'de>,
+{
+ struct QListDeserializer(*mut bindings::QListEntry, usize);
+
+ impl<'de> SeqAccess<'de> for QListDeserializer {
+ type Error = Error;
+
+ fn next_element_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>>
+ where
+ T: DeserializeSeed<'de>,
+ {
+ if self.0.is_null() {
+ return Ok(None);
+ }
+
+ let e = unsafe { &*self.0 };
+ // increment the reference count because deserialize consumes
`value`.
+ let value = unsafe {
QObject::cloned_from_raw(e.value.cast_const()) };
+ let result = seed.deserialize(value);
+ self.0 = unsafe { e.next.tqe_next };
+ self.1 += 1;
+ result.map(Some)
+ }
+ }
+
+ let mut deserializer = QListDeserializer(unsafe { qlist.head.tqh_first },
0);
+ let seq = visitor.visit_seq(&mut deserializer)?;
+ if deserializer.0.is_null() {
+ Ok(seq)
+ } else {
+ Err(serde::de::Error::invalid_length(
+ deserializer.1,
+ &"fewer elements in array",
+ ))
+ }
+}
+
+fn visit_qdict_ref<'de, V>(qdict: &'de bindings::QDict, visitor: V) ->
Result<V::Value>
+where
+ V: Visitor<'de>,
+{
+ struct QDictDeserializer(*mut bindings::QDict, *const
bindings::QDictEntry);
+
+ impl<'de> MapAccess<'de> for QDictDeserializer {
+ type Error = Error;
+
+ fn next_key_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>>
+ where
+ T: DeserializeSeed<'de>,
+ {
+ if self.1.is_null() {
+ return Ok(None);
+ }
+
+ let e = unsafe { &*self.1 };
+ let key = unsafe { CStr::from_ptr(e.key) };
+ let key_de = StrDeserializer::new(key.to_str()?);
+ seed.deserialize(key_de).map(Some)
+ }
+
+ fn next_value_seed<T>(&mut self, seed: T) -> Result<T::Value>
+ where
+ T: DeserializeSeed<'de>,
+ {
+ if self.1.is_null() {
+ panic!("next_key must have returned None");
+ }
+
+ let e = unsafe { &*self.1 };
+ // increment the reference count because deserialize consumes
`value`.
+ let value = unsafe { QObject::cloned_from_raw(e.value) };
+ let result = seed.deserialize(value);
+ self.1 = unsafe { bindings::qdict_next(self.0, self.1) };
+ result
+ }
+ }
+
+ let qdict = (qdict as *const bindings::QDict).cast_mut();
+ let e = unsafe { &*bindings::qdict_first(qdict) };
+ let mut deserializer = QDictDeserializer(qdict, e);
+ let map = visitor.visit_map(&mut deserializer)?;
+ if deserializer.1.is_null() {
+ Ok(map)
+ } else {
+ Err(serde::de::Error::invalid_length(
+ unsafe { bindings::qdict_size(qdict) },
+ &"fewer elements in map",
+ ))
+ }
+}
+
+fn visit_qnum_ref<'de, V>(qnum: QObject, visitor: V) -> Result<V::Value>
+where
+ V: Visitor<'de>,
+{
+ match_qobject! { (qnum) =>
+ i64(n) => visitor.visit_i64(n),
+ u64(n) => visitor.visit_u64(n),
+ f64(n) => visitor.visit_f64(n),
+ _ => Err(qnum.invalid_type(&"number")),
+ }
+}
+
+macro_rules! deserialize_number {
+ ($method:ident) => {
+ fn $method<V>(self, visitor: V) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ visit_qnum_ref(self, visitor)
+ }
+ };
+}
+impl<'de> serde::Deserializer<'de> for QObject {
+ type Error = Error;
+
+ fn deserialize_any<V>(self, visitor: V) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ match_qobject! { (self) =>
+ () => visitor.visit_unit(),
+ bool(v) => visitor.visit_bool(v),
+ i64(n) => visitor.visit_i64(n),
+ u64(n) => visitor.visit_u64(n),
+ f64(n) => visitor.visit_f64(n),
+ CStr(cstr) => visitor.visit_borrowed_str(cstr.to_str()?),
+ QList(qlist) => visit_qlist_ref(qlist, visitor),
+ QDict(qdict) => visit_qdict_ref(qdict, visitor),
+ }
+ }
+
+ deserialize_number!(deserialize_i8);
+ deserialize_number!(deserialize_i16);
+ deserialize_number!(deserialize_i32);
+ deserialize_number!(deserialize_i64);
+ deserialize_number!(deserialize_i128);
+ deserialize_number!(deserialize_u8);
+ deserialize_number!(deserialize_u16);
+ deserialize_number!(deserialize_u32);
+ deserialize_number!(deserialize_u64);
+ deserialize_number!(deserialize_u128);
+ deserialize_number!(deserialize_f32);
+ deserialize_number!(deserialize_f64);
+
+ fn deserialize_option<V>(self, visitor: V) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ match_qobject! { (self) =>
+ () => visitor.visit_none(),
+ _ => visitor.visit_some(self),
+ }
+ }
+
+ fn deserialize_enum<V>(
+ self,
+ _name: &'static str,
+ _variants: &'static [&'static str],
+ visitor: V,
+ ) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ match_qobject! { (self) =>
+ CStr(cstr) => visitor.visit_borrowed_str(cstr.to_str()?),
+ QDict(qdict) => visit_qdict_ref(qdict, visitor),
+ _ => Err(self.invalid_type(&"string or map")),
+ }
+ }
+
+ #[inline]
+ fn deserialize_newtype_struct<V>(self, name: &'static str, visitor: V) ->
Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ let _ = name;
+ visitor.visit_newtype_struct(self)
+ }
+
+ fn deserialize_bool<V>(self, visitor: V) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ match_qobject! { (self) =>
+ bool(v) => visitor.visit_bool(v),
+ _ => Err(self.invalid_type(&visitor)),
+ }
+ }
+
+ fn deserialize_char<V>(self, visitor: V) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ self.deserialize_str(visitor)
+ }
+
+ fn deserialize_str<V>(self, visitor: V) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ match_qobject! { (self) =>
+ CStr(cstr) => visitor.visit_borrowed_str(cstr.to_str()?),
+ _ => Err(self.invalid_type(&visitor)),
+ }
+ }
+
+ fn deserialize_string<V>(self, visitor: V) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ self.deserialize_str(visitor)
+ }
+
+ fn deserialize_bytes<V>(self, visitor: V) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ match_qobject! { (self) =>
+ CStr(cstr) => visitor.visit_borrowed_str(cstr.to_str()?),
+ QList(qlist) => visit_qlist_ref(qlist, visitor),
+ _ => Err(self.invalid_type(&visitor)),
+ }
+ }
+
+ fn deserialize_byte_buf<V>(self, visitor: V) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ self.deserialize_bytes(visitor)
+ }
+
+ fn deserialize_unit<V>(self, visitor: V) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ match_qobject! { (self) =>
+ () => visitor.visit_unit(),
+ _ => Err(self.invalid_type(&visitor)),
+ }
+ }
+
+ fn deserialize_unit_struct<V>(self, _name: &'static str, visitor: V) ->
Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ self.deserialize_unit(visitor)
+ }
+
+ fn deserialize_seq<V>(self, visitor: V) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ match_qobject! { (self) =>
+ QList(qlist) => visit_qlist_ref(qlist, visitor),
+ _ => Err(self.invalid_type(&visitor)),
+ }
+ }
+
+ fn deserialize_tuple<V>(self, _len: usize, visitor: V) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ self.deserialize_seq(visitor)
+ }
+
+ fn deserialize_tuple_struct<V>(
+ self,
+ _name: &'static str,
+ _len: usize,
+ visitor: V,
+ ) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ self.deserialize_seq(visitor)
+ }
+
+ fn deserialize_map<V>(self, visitor: V) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ match_qobject! { (self) =>
+ QDict(qdict) => visit_qdict_ref(qdict, visitor),
+ _ => Err(self.invalid_type(&visitor)),
+ }
+ }
+
+ fn deserialize_struct<V>(
+ self,
+ _name: &'static str,
+ _fields: &'static [&'static str],
+ visitor: V,
+ ) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ match_qobject! { (self) =>
+ QList(qlist) => visit_qlist_ref(qlist, visitor),
+ QDict(qdict) => visit_qdict_ref(qdict, visitor),
+ _ => Err(self.invalid_type(&visitor)),
+ }
+ }
+
+ fn deserialize_identifier<V>(self, visitor: V) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ self.deserialize_str(visitor)
+ }
+
+ fn deserialize_ignored_any<V>(self, visitor: V) -> Result<V::Value>
+ where
+ V: Visitor<'de>,
+ {
+ visitor.visit_unit()
+ }
+}
+
+pub fn from_qobject<T>(value: QObject) -> Result<T>
+where
+ T: de::DeserializeOwned,
+{
+ T::deserialize(value)
+}
diff --git a/rust/util/src/qobject/error.rs b/rust/util/src/qobject/error.rs
index 5212e65c4f7..2d7c180187a 100644
--- a/rust/util/src/qobject/error.rs
+++ b/rust/util/src/qobject/error.rs
@@ -6,7 +6,7 @@
str::Utf8Error,
};
-use serde::ser;
+use serde::{de, ser};
#[derive(Debug)]
pub enum Error {
@@ -23,6 +23,12 @@ fn custom<T: Display>(msg: T) -> Self {
}
}
+impl de::Error for Error {
+ fn custom<T: Display>(msg: T) -> Self {
+ Error::Custom(msg.to_string())
+ }
+}
+
impl From<NulError> for Error {
fn from(_: NulError) -> Self {
Error::NulEncountered
diff --git a/rust/util/src/qobject/mod.rs b/rust/util/src/qobject/mod.rs
index aec635a5ccc..1c18a491720 100644
--- a/rust/util/src/qobject/mod.rs
+++ b/rust/util/src/qobject/mod.rs
@@ -7,6 +7,7 @@
#![deny(clippy::unwrap_used)]
mod deserialize;
+mod deserializer;
mod error;
mod serialize;
mod serializer;
@@ -20,6 +21,7 @@
};
use common::assert_field_type;
+pub use deserializer::from_qobject;
pub use error::{Error, Result};
pub use serializer::to_qobject;
--
2.51.0
