|  | /* | 
|  | * Copyright (C) 2020 The Android Open Source Project | 
|  | * | 
|  | * Licensed under the Apache License, Version 2.0 (the "License"); | 
|  | * you may not use this file except in compliance with the License. | 
|  | * You may obtain a copy of the License at | 
|  | * | 
|  | *      http://www.apache.org/licenses/LICENSE-2.0 | 
|  | * | 
|  | * Unless required by applicable law or agreed to in writing, software | 
|  | * distributed under the License is distributed on an "AS IS" BASIS, | 
|  | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | 
|  | * See the License for the specific language governing permissions and | 
|  | * limitations under the License. | 
|  | */ | 
|  |  | 
|  | //! Container for messages that are sent via binder. | 
|  |  | 
|  | use crate::binder::AsNative; | 
|  | use crate::error::{status_result, Result, StatusCode}; | 
|  | use crate::proxy::SpIBinder; | 
|  | use crate::sys; | 
|  |  | 
|  | use std::convert::TryInto; | 
|  | use std::marker::PhantomData; | 
|  | use std::mem::ManuallyDrop; | 
|  | use std::ptr::{self, NonNull}; | 
|  | use std::fmt; | 
|  |  | 
|  | mod file_descriptor; | 
|  | mod parcelable; | 
|  | mod parcelable_holder; | 
|  |  | 
|  | pub use self::file_descriptor::ParcelFileDescriptor; | 
|  | pub use self::parcelable::{ | 
|  | Deserialize, DeserializeArray, DeserializeOption, Serialize, SerializeArray, SerializeOption, | 
|  | Parcelable, NON_NULL_PARCELABLE_FLAG, NULL_PARCELABLE_FLAG, | 
|  | }; | 
|  | pub use self::parcelable_holder::{ParcelableHolder, ParcelableMetadata}; | 
|  |  | 
|  | /// Container for a message (data and object references) that can be sent | 
|  | /// through Binder. | 
|  | /// | 
|  | /// A Parcel can contain both serialized data that will be deserialized on the | 
|  | /// other side of the IPC, and references to live Binder objects that will | 
|  | /// result in the other side receiving a proxy Binder connected with the | 
|  | /// original Binder in the Parcel. | 
|  | /// | 
|  | /// This type represents a parcel that is owned by Rust code. | 
|  | #[repr(transparent)] | 
|  | pub struct Parcel { | 
|  | ptr: NonNull<sys::AParcel>, | 
|  | } | 
|  |  | 
|  | /// # Safety | 
|  | /// | 
|  | /// This type guarantees that it owns the AParcel and that all access to | 
|  | /// the AParcel happens through the Parcel, so it is ok to send across | 
|  | /// threads. | 
|  | unsafe impl Send for Parcel {} | 
|  |  | 
|  | /// Container for a message (data and object references) that can be sent | 
|  | /// through Binder. | 
|  | /// | 
|  | /// This object is a borrowed variant of [`Parcel`]. It is a separate type from | 
|  | /// `&mut Parcel` because it is not valid to `mem::swap` two parcels. | 
|  | #[repr(transparent)] | 
|  | pub struct BorrowedParcel<'a> { | 
|  | ptr: NonNull<sys::AParcel>, | 
|  | _lifetime: PhantomData<&'a mut Parcel>, | 
|  | } | 
|  |  | 
|  | impl Parcel { | 
|  | /// Create a new empty `Parcel`. | 
|  | pub fn new() -> Parcel { | 
|  | let ptr = unsafe { | 
|  | // Safety: If `AParcel_create` succeeds, it always returns | 
|  | // a valid pointer. If it fails, the process will crash. | 
|  | sys::AParcel_create() | 
|  | }; | 
|  | Self { | 
|  | ptr: NonNull::new(ptr).expect("AParcel_create returned null pointer") | 
|  | } | 
|  | } | 
|  |  | 
|  | /// Create an owned reference to a parcel object from a raw pointer. | 
|  | /// | 
|  | /// # Safety | 
|  | /// | 
|  | /// This constructor is safe if the raw pointer parameter is either null | 
|  | /// (resulting in `None`), or a valid pointer to an `AParcel` object. The | 
|  | /// parcel object must be owned by the caller prior to this call, as this | 
|  | /// constructor takes ownership of the parcel and will destroy it on drop. | 
|  | /// | 
|  | /// Additionally, the caller must guarantee that it is valid to take | 
|  | /// ownership of the AParcel object. All future access to the AParcel | 
|  | /// must happen through this `Parcel`. | 
|  | /// | 
|  | /// Because `Parcel` implements `Send`, the pointer must never point to any | 
|  | /// thread-local data, e.g., a variable on the stack, either directly or | 
|  | /// indirectly. | 
|  | pub unsafe fn from_raw(ptr: *mut sys::AParcel) -> Option<Parcel> { | 
|  | NonNull::new(ptr).map(|ptr| Self { ptr }) | 
|  | } | 
|  |  | 
|  | /// Consume the parcel, transferring ownership to the caller. | 
|  | pub(crate) fn into_raw(self) -> *mut sys::AParcel { | 
|  | let ptr = self.ptr.as_ptr(); | 
|  | let _ = ManuallyDrop::new(self); | 
|  | ptr | 
|  | } | 
|  |  | 
|  | /// Get a borrowed view into the contents of this `Parcel`. | 
|  | pub fn borrowed(&mut self) -> BorrowedParcel<'_> { | 
|  | // Safety: The raw pointer is a valid pointer to an AParcel, and the | 
|  | // lifetime of the returned `BorrowedParcel` is tied to `self`, so the | 
|  | // borrow checker will ensure that the `AParcel` can only be accessed | 
|  | // via the `BorrowParcel` until it goes out of scope. | 
|  | BorrowedParcel { | 
|  | ptr: self.ptr, | 
|  | _lifetime: PhantomData, | 
|  | } | 
|  | } | 
|  |  | 
|  | /// Get an immutable borrowed view into the contents of this `Parcel`. | 
|  | pub fn borrowed_ref(&self) -> &BorrowedParcel<'_> { | 
|  | // Safety: Parcel and BorrowedParcel are both represented in the same | 
|  | // way as a NonNull<sys::AParcel> due to their use of repr(transparent), | 
|  | // so casting references as done here is valid. | 
|  | unsafe { | 
|  | &*(self as *const Parcel as *const BorrowedParcel<'_>) | 
|  | } | 
|  | } | 
|  | } | 
|  |  | 
|  | impl Default for Parcel { | 
|  | fn default() -> Self { | 
|  | Self::new() | 
|  | } | 
|  | } | 
|  |  | 
|  | impl Clone for Parcel { | 
|  | fn clone(&self) -> Self { | 
|  | let mut new_parcel = Self::new(); | 
|  | new_parcel | 
|  | .borrowed() | 
|  | .append_all_from(self.borrowed_ref()) | 
|  | .expect("Failed to append from Parcel"); | 
|  | new_parcel | 
|  | } | 
|  | } | 
|  |  | 
|  | impl<'a> BorrowedParcel<'a> { | 
|  | /// Create a borrowed reference to a parcel object from a raw pointer. | 
|  | /// | 
|  | /// # Safety | 
|  | /// | 
|  | /// This constructor is safe if the raw pointer parameter is either null | 
|  | /// (resulting in `None`), or a valid pointer to an `AParcel` object. | 
|  | /// | 
|  | /// Since the raw pointer is not restricted by any lifetime, the lifetime on | 
|  | /// the returned `BorrowedParcel` object can be chosen arbitrarily by the | 
|  | /// caller. The caller must ensure it is valid to mutably borrow the AParcel | 
|  | /// for the duration of the lifetime that the caller chooses. Note that | 
|  | /// since this is a mutable borrow, it must have exclusive access to the | 
|  | /// AParcel for the duration of the borrow. | 
|  | pub unsafe fn from_raw(ptr: *mut sys::AParcel) -> Option<BorrowedParcel<'a>> { | 
|  | Some(Self { | 
|  | ptr: NonNull::new(ptr)?, | 
|  | _lifetime: PhantomData, | 
|  | }) | 
|  | } | 
|  |  | 
|  | /// Get a sub-reference to this reference to the parcel. | 
|  | pub fn reborrow(&mut self) -> BorrowedParcel<'_> { | 
|  | // Safety: The raw pointer is a valid pointer to an AParcel, and the | 
|  | // lifetime of the returned `BorrowedParcel` is tied to `self`, so the | 
|  | // borrow checker will ensure that the `AParcel` can only be accessed | 
|  | // via the `BorrowParcel` until it goes out of scope. | 
|  | BorrowedParcel { | 
|  | ptr: self.ptr, | 
|  | _lifetime: PhantomData, | 
|  | } | 
|  | } | 
|  | } | 
|  |  | 
|  | /// # Safety | 
|  | /// | 
|  | /// The `Parcel` constructors guarantee that a `Parcel` object will always | 
|  | /// contain a valid pointer to an `AParcel`. | 
|  | unsafe impl AsNative<sys::AParcel> for Parcel { | 
|  | fn as_native(&self) -> *const sys::AParcel { | 
|  | self.ptr.as_ptr() | 
|  | } | 
|  |  | 
|  | fn as_native_mut(&mut self) -> *mut sys::AParcel { | 
|  | self.ptr.as_ptr() | 
|  | } | 
|  | } | 
|  |  | 
|  | /// # Safety | 
|  | /// | 
|  | /// The `BorrowedParcel` constructors guarantee that a `BorrowedParcel` object | 
|  | /// will always contain a valid pointer to an `AParcel`. | 
|  | unsafe impl<'a> AsNative<sys::AParcel> for BorrowedParcel<'a> { | 
|  | fn as_native(&self) -> *const sys::AParcel { | 
|  | self.ptr.as_ptr() | 
|  | } | 
|  |  | 
|  | fn as_native_mut(&mut self) -> *mut sys::AParcel { | 
|  | self.ptr.as_ptr() | 
|  | } | 
|  | } | 
|  |  | 
|  | // Data serialization methods | 
|  | impl<'a> BorrowedParcel<'a> { | 
|  | /// Data written to parcelable is zero'd before being deleted or reallocated. | 
|  | pub fn mark_sensitive(&mut self) { | 
|  | unsafe { | 
|  | // Safety: guaranteed to have a parcel object, and this method never fails | 
|  | sys::AParcel_markSensitive(self.as_native()) | 
|  | } | 
|  | } | 
|  |  | 
|  | /// Write a type that implements [`Serialize`] to the parcel. | 
|  | pub fn write<S: Serialize + ?Sized>(&mut self, parcelable: &S) -> Result<()> { | 
|  | parcelable.serialize(self) | 
|  | } | 
|  |  | 
|  | /// Writes the length of a slice to the parcel. | 
|  | /// | 
|  | /// This is used in AIDL-generated client side code to indicate the | 
|  | /// allocated space for an output array parameter. | 
|  | pub fn write_slice_size<T>(&mut self, slice: Option<&[T]>) -> Result<()> { | 
|  | if let Some(slice) = slice { | 
|  | let len: i32 = slice.len().try_into().or(Err(StatusCode::BAD_VALUE))?; | 
|  | self.write(&len) | 
|  | } else { | 
|  | self.write(&-1i32) | 
|  | } | 
|  | } | 
|  |  | 
|  | /// Perform a series of writes to the parcel, prepended with the length | 
|  | /// (in bytes) of the written data. | 
|  | /// | 
|  | /// The length `0i32` will be written to the parcel first, followed by the | 
|  | /// writes performed by the callback. The initial length will then be | 
|  | /// updated to the length of all data written by the callback, plus the | 
|  | /// size of the length elemement itself (4 bytes). | 
|  | /// | 
|  | /// # Examples | 
|  | /// | 
|  | /// After the following call: | 
|  | /// | 
|  | /// ``` | 
|  | /// # use binder::{Binder, Interface, Parcel}; | 
|  | /// # let mut parcel = Parcel::new(); | 
|  | /// parcel.sized_write(|subparcel| { | 
|  | ///     subparcel.write(&1u32)?; | 
|  | ///     subparcel.write(&2u32)?; | 
|  | ///     subparcel.write(&3u32) | 
|  | /// }); | 
|  | /// ``` | 
|  | /// | 
|  | /// `parcel` will contain the following: | 
|  | /// | 
|  | /// ```ignore | 
|  | /// [16i32, 1u32, 2u32, 3u32] | 
|  | /// ``` | 
|  | pub fn sized_write<F>(&mut self, f: F) -> Result<()> | 
|  | where | 
|  | for<'b> F: FnOnce(&'b mut WritableSubParcel<'b>) -> Result<()> | 
|  | { | 
|  | let start = self.get_data_position(); | 
|  | self.write(&0i32)?; | 
|  | { | 
|  | let mut subparcel = WritableSubParcel(self.reborrow()); | 
|  | f(&mut subparcel)?; | 
|  | } | 
|  | let end = self.get_data_position(); | 
|  | unsafe { | 
|  | self.set_data_position(start)?; | 
|  | } | 
|  | assert!(end >= start); | 
|  | self.write(&(end - start))?; | 
|  | unsafe { | 
|  | self.set_data_position(end)?; | 
|  | } | 
|  | Ok(()) | 
|  | } | 
|  |  | 
|  | /// Returns the current position in the parcel data. | 
|  | pub fn get_data_position(&self) -> i32 { | 
|  | unsafe { | 
|  | // Safety: `BorrowedParcel` always contains a valid pointer to an | 
|  | // `AParcel`, and this call is otherwise safe. | 
|  | sys::AParcel_getDataPosition(self.as_native()) | 
|  | } | 
|  | } | 
|  |  | 
|  | /// Returns the total size of the parcel. | 
|  | pub fn get_data_size(&self) -> i32 { | 
|  | unsafe { | 
|  | // Safety: `BorrowedParcel` always contains a valid pointer to an | 
|  | // `AParcel`, and this call is otherwise safe. | 
|  | sys::AParcel_getDataSize(self.as_native()) | 
|  | } | 
|  | } | 
|  |  | 
|  | /// Move the current read/write position in the parcel. | 
|  | /// | 
|  | /// # Safety | 
|  | /// | 
|  | /// This method is safe if `pos` is less than the current size of the parcel | 
|  | /// data buffer. Otherwise, we are relying on correct bounds checking in the | 
|  | /// Parcel C++ code on every subsequent read or write to this parcel. If all | 
|  | /// accesses are bounds checked, this call is still safe, but we can't rely | 
|  | /// on that. | 
|  | pub unsafe fn set_data_position(&self, pos: i32) -> Result<()> { | 
|  | status_result(sys::AParcel_setDataPosition(self.as_native(), pos)) | 
|  | } | 
|  |  | 
|  | /// Append a subset of another parcel. | 
|  | /// | 
|  | /// This appends `size` bytes of data from `other` starting at offset | 
|  | /// `start` to the current parcel, or returns an error if not possible. | 
|  | pub fn append_from(&mut self, other: &impl AsNative<sys::AParcel>, start: i32, size: i32) -> Result<()> { | 
|  | let status = unsafe { | 
|  | // Safety: `Parcel::appendFrom` from C++ checks that `start` | 
|  | // and `size` are in bounds, and returns an error otherwise. | 
|  | // Both `self` and `other` always contain valid pointers. | 
|  | sys::AParcel_appendFrom( | 
|  | other.as_native(), | 
|  | self.as_native_mut(), | 
|  | start, | 
|  | size, | 
|  | ) | 
|  | }; | 
|  | status_result(status) | 
|  | } | 
|  |  | 
|  | /// Append the contents of another parcel. | 
|  | pub fn append_all_from(&mut self, other: &impl AsNative<sys::AParcel>) -> Result<()> { | 
|  | // Safety: `BorrowedParcel` always contains a valid pointer to an | 
|  | // `AParcel`, and this call is otherwise safe. | 
|  | let size = unsafe { sys::AParcel_getDataSize(other.as_native()) }; | 
|  | self.append_from(other, 0, size) | 
|  | } | 
|  | } | 
|  |  | 
|  | /// A segment of a writable parcel, used for [`BorrowedParcel::sized_write`]. | 
|  | pub struct WritableSubParcel<'a>(BorrowedParcel<'a>); | 
|  |  | 
|  | impl<'a> WritableSubParcel<'a> { | 
|  | /// Write a type that implements [`Serialize`] to the sub-parcel. | 
|  | pub fn write<S: Serialize + ?Sized>(&mut self, parcelable: &S) -> Result<()> { | 
|  | parcelable.serialize(&mut self.0) | 
|  | } | 
|  | } | 
|  |  | 
|  | impl Parcel { | 
|  | /// Data written to parcelable is zero'd before being deleted or reallocated. | 
|  | pub fn mark_sensitive(&mut self) { | 
|  | self.borrowed().mark_sensitive() | 
|  | } | 
|  |  | 
|  | /// Write a type that implements [`Serialize`] to the parcel. | 
|  | pub fn write<S: Serialize + ?Sized>(&mut self, parcelable: &S) -> Result<()> { | 
|  | self.borrowed().write(parcelable) | 
|  | } | 
|  |  | 
|  | /// Writes the length of a slice to the parcel. | 
|  | /// | 
|  | /// This is used in AIDL-generated client side code to indicate the | 
|  | /// allocated space for an output array parameter. | 
|  | pub fn write_slice_size<T>(&mut self, slice: Option<&[T]>) -> Result<()> { | 
|  | self.borrowed().write_slice_size(slice) | 
|  | } | 
|  |  | 
|  | /// Perform a series of writes to the parcel, prepended with the length | 
|  | /// (in bytes) of the written data. | 
|  | /// | 
|  | /// The length `0i32` will be written to the parcel first, followed by the | 
|  | /// writes performed by the callback. The initial length will then be | 
|  | /// updated to the length of all data written by the callback, plus the | 
|  | /// size of the length elemement itself (4 bytes). | 
|  | /// | 
|  | /// # Examples | 
|  | /// | 
|  | /// After the following call: | 
|  | /// | 
|  | /// ``` | 
|  | /// # use binder::{Binder, Interface, Parcel}; | 
|  | /// # let mut parcel = Parcel::new(); | 
|  | /// parcel.sized_write(|subparcel| { | 
|  | ///     subparcel.write(&1u32)?; | 
|  | ///     subparcel.write(&2u32)?; | 
|  | ///     subparcel.write(&3u32) | 
|  | /// }); | 
|  | /// ``` | 
|  | /// | 
|  | /// `parcel` will contain the following: | 
|  | /// | 
|  | /// ```ignore | 
|  | /// [16i32, 1u32, 2u32, 3u32] | 
|  | /// ``` | 
|  | pub fn sized_write<F>(&mut self, f: F) -> Result<()> | 
|  | where | 
|  | for<'b> F: FnOnce(&'b mut WritableSubParcel<'b>) -> Result<()> | 
|  | { | 
|  | self.borrowed().sized_write(f) | 
|  | } | 
|  |  | 
|  | /// Returns the current position in the parcel data. | 
|  | pub fn get_data_position(&self) -> i32 { | 
|  | self.borrowed_ref().get_data_position() | 
|  | } | 
|  |  | 
|  | /// Returns the total size of the parcel. | 
|  | pub fn get_data_size(&self) -> i32 { | 
|  | self.borrowed_ref().get_data_size() | 
|  | } | 
|  |  | 
|  | /// Move the current read/write position in the parcel. | 
|  | /// | 
|  | /// # Safety | 
|  | /// | 
|  | /// This method is safe if `pos` is less than the current size of the parcel | 
|  | /// data buffer. Otherwise, we are relying on correct bounds checking in the | 
|  | /// Parcel C++ code on every subsequent read or write to this parcel. If all | 
|  | /// accesses are bounds checked, this call is still safe, but we can't rely | 
|  | /// on that. | 
|  | pub unsafe fn set_data_position(&self, pos: i32) -> Result<()> { | 
|  | self.borrowed_ref().set_data_position(pos) | 
|  | } | 
|  |  | 
|  | /// Append a subset of another parcel. | 
|  | /// | 
|  | /// This appends `size` bytes of data from `other` starting at offset | 
|  | /// `start` to the current parcel, or returns an error if not possible. | 
|  | pub fn append_from(&mut self, other: &impl AsNative<sys::AParcel>, start: i32, size: i32) -> Result<()> { | 
|  | self.borrowed().append_from(other, start, size) | 
|  | } | 
|  |  | 
|  | /// Append the contents of another parcel. | 
|  | pub fn append_all_from(&mut self, other: &impl AsNative<sys::AParcel>) -> Result<()> { | 
|  | self.borrowed().append_all_from(other) | 
|  | } | 
|  | } | 
|  |  | 
|  | // Data deserialization methods | 
|  | impl<'a> BorrowedParcel<'a> { | 
|  | /// Attempt to read a type that implements [`Deserialize`] from this parcel. | 
|  | pub fn read<D: Deserialize>(&self) -> Result<D> { | 
|  | D::deserialize(self) | 
|  | } | 
|  |  | 
|  | /// Attempt to read a type that implements [`Deserialize`] from this parcel | 
|  | /// onto an existing value. This operation will overwrite the old value | 
|  | /// partially or completely, depending on how much data is available. | 
|  | pub fn read_onto<D: Deserialize>(&self, x: &mut D) -> Result<()> { | 
|  | x.deserialize_from(self) | 
|  | } | 
|  |  | 
|  | /// Safely read a sized parcelable. | 
|  | /// | 
|  | /// Read the size of a parcelable, compute the end position | 
|  | /// of that parcelable, then build a sized readable sub-parcel | 
|  | /// and call a closure with the sub-parcel as its parameter. | 
|  | /// The closure can keep reading data from the sub-parcel | 
|  | /// until it runs out of input data. The closure is responsible | 
|  | /// for calling [`ReadableSubParcel::has_more_data`] to check for | 
|  | /// more data before every read, at least until Rust generators | 
|  | /// are stabilized. | 
|  | /// After the closure returns, skip to the end of the current | 
|  | /// parcelable regardless of how much the closure has read. | 
|  | /// | 
|  | /// # Examples | 
|  | /// | 
|  | /// ```no_run | 
|  | /// let mut parcelable = Default::default(); | 
|  | /// parcel.sized_read(|subparcel| { | 
|  | ///     if subparcel.has_more_data() { | 
|  | ///         parcelable.a = subparcel.read()?; | 
|  | ///     } | 
|  | ///     if subparcel.has_more_data() { | 
|  | ///         parcelable.b = subparcel.read()?; | 
|  | ///     } | 
|  | ///     Ok(()) | 
|  | /// }); | 
|  | /// ``` | 
|  | /// | 
|  | pub fn sized_read<F>(&self, f: F) -> Result<()> | 
|  | where | 
|  | for<'b> F: FnOnce(ReadableSubParcel<'b>) -> Result<()> | 
|  | { | 
|  | let start = self.get_data_position(); | 
|  | let parcelable_size: i32 = self.read()?; | 
|  | if parcelable_size < 4 { | 
|  | return Err(StatusCode::BAD_VALUE); | 
|  | } | 
|  |  | 
|  | let end = start.checked_add(parcelable_size) | 
|  | .ok_or(StatusCode::BAD_VALUE)?; | 
|  | if end > self.get_data_size() { | 
|  | return Err(StatusCode::NOT_ENOUGH_DATA); | 
|  | } | 
|  |  | 
|  | let subparcel = ReadableSubParcel { | 
|  | parcel: BorrowedParcel { | 
|  | ptr: self.ptr, | 
|  | _lifetime: PhantomData, | 
|  | }, | 
|  | end_position: end, | 
|  | }; | 
|  | f(subparcel)?; | 
|  |  | 
|  | // Advance the data position to the actual end, | 
|  | // in case the closure read less data than was available | 
|  | unsafe { | 
|  | self.set_data_position(end)?; | 
|  | } | 
|  |  | 
|  | Ok(()) | 
|  | } | 
|  |  | 
|  | /// Read a vector size from the parcel and resize the given output vector to | 
|  | /// be correctly sized for that amount of data. | 
|  | /// | 
|  | /// This method is used in AIDL-generated server side code for methods that | 
|  | /// take a mutable slice reference parameter. | 
|  | pub fn resize_out_vec<D: Default + Deserialize>(&self, out_vec: &mut Vec<D>) -> Result<()> { | 
|  | let len: i32 = self.read()?; | 
|  |  | 
|  | if len < 0 { | 
|  | return Err(StatusCode::UNEXPECTED_NULL); | 
|  | } | 
|  |  | 
|  | // usize in Rust may be 16-bit, so i32 may not fit | 
|  | let len = len.try_into().unwrap(); | 
|  | out_vec.resize_with(len, Default::default); | 
|  |  | 
|  | Ok(()) | 
|  | } | 
|  |  | 
|  | /// Read a vector size from the parcel and either create a correctly sized | 
|  | /// vector for that amount of data or set the output parameter to None if | 
|  | /// the vector should be null. | 
|  | /// | 
|  | /// This method is used in AIDL-generated server side code for methods that | 
|  | /// take a mutable slice reference parameter. | 
|  | pub fn resize_nullable_out_vec<D: Default + Deserialize>( | 
|  | &self, | 
|  | out_vec: &mut Option<Vec<D>>, | 
|  | ) -> Result<()> { | 
|  | let len: i32 = self.read()?; | 
|  |  | 
|  | if len < 0 { | 
|  | *out_vec = None; | 
|  | } else { | 
|  | // usize in Rust may be 16-bit, so i32 may not fit | 
|  | let len = len.try_into().unwrap(); | 
|  | let mut vec = Vec::with_capacity(len); | 
|  | vec.resize_with(len, Default::default); | 
|  | *out_vec = Some(vec); | 
|  | } | 
|  |  | 
|  | Ok(()) | 
|  | } | 
|  | } | 
|  |  | 
|  | /// A segment of a readable parcel, used for [`Parcel::sized_read`]. | 
|  | pub struct ReadableSubParcel<'a> { | 
|  | parcel: BorrowedParcel<'a>, | 
|  | end_position: i32, | 
|  | } | 
|  |  | 
|  | impl<'a> ReadableSubParcel<'a> { | 
|  | /// Read a type that implements [`Deserialize`] from the sub-parcel. | 
|  | pub fn read<D: Deserialize>(&self) -> Result<D> { | 
|  | // The caller should have checked this, | 
|  | // but it can't hurt to double-check | 
|  | assert!(self.has_more_data()); | 
|  | D::deserialize(&self.parcel) | 
|  | } | 
|  |  | 
|  | /// Check if the sub-parcel has more data to read | 
|  | pub fn has_more_data(&self) -> bool { | 
|  | self.parcel.get_data_position() < self.end_position | 
|  | } | 
|  | } | 
|  |  | 
|  | impl Parcel { | 
|  | /// Attempt to read a type that implements [`Deserialize`] from this parcel. | 
|  | pub fn read<D: Deserialize>(&self) -> Result<D> { | 
|  | self.borrowed_ref().read() | 
|  | } | 
|  |  | 
|  | /// Attempt to read a type that implements [`Deserialize`] from this parcel | 
|  | /// onto an existing value. This operation will overwrite the old value | 
|  | /// partially or completely, depending on how much data is available. | 
|  | pub fn read_onto<D: Deserialize>(&self, x: &mut D) -> Result<()> { | 
|  | self.borrowed_ref().read_onto(x) | 
|  | } | 
|  |  | 
|  | /// Safely read a sized parcelable. | 
|  | /// | 
|  | /// Read the size of a parcelable, compute the end position | 
|  | /// of that parcelable, then build a sized readable sub-parcel | 
|  | /// and call a closure with the sub-parcel as its parameter. | 
|  | /// The closure can keep reading data from the sub-parcel | 
|  | /// until it runs out of input data. The closure is responsible | 
|  | /// for calling [`ReadableSubParcel::has_more_data`] to check for | 
|  | /// more data before every read, at least until Rust generators | 
|  | /// are stabilized. | 
|  | /// After the closure returns, skip to the end of the current | 
|  | /// parcelable regardless of how much the closure has read. | 
|  | /// | 
|  | /// # Examples | 
|  | /// | 
|  | /// ```no_run | 
|  | /// let mut parcelable = Default::default(); | 
|  | /// parcel.sized_read(|subparcel| { | 
|  | ///     if subparcel.has_more_data() { | 
|  | ///         parcelable.a = subparcel.read()?; | 
|  | ///     } | 
|  | ///     if subparcel.has_more_data() { | 
|  | ///         parcelable.b = subparcel.read()?; | 
|  | ///     } | 
|  | ///     Ok(()) | 
|  | /// }); | 
|  | /// ``` | 
|  | /// | 
|  | pub fn sized_read<F>(&self, f: F) -> Result<()> | 
|  | where | 
|  | for<'b> F: FnOnce(ReadableSubParcel<'b>) -> Result<()> | 
|  | { | 
|  | self.borrowed_ref().sized_read(f) | 
|  | } | 
|  |  | 
|  | /// Read a vector size from the parcel and resize the given output vector to | 
|  | /// be correctly sized for that amount of data. | 
|  | /// | 
|  | /// This method is used in AIDL-generated server side code for methods that | 
|  | /// take a mutable slice reference parameter. | 
|  | pub fn resize_out_vec<D: Default + Deserialize>(&self, out_vec: &mut Vec<D>) -> Result<()> { | 
|  | self.borrowed_ref().resize_out_vec(out_vec) | 
|  | } | 
|  |  | 
|  | /// Read a vector size from the parcel and either create a correctly sized | 
|  | /// vector for that amount of data or set the output parameter to None if | 
|  | /// the vector should be null. | 
|  | /// | 
|  | /// This method is used in AIDL-generated server side code for methods that | 
|  | /// take a mutable slice reference parameter. | 
|  | pub fn resize_nullable_out_vec<D: Default + Deserialize>( | 
|  | &self, | 
|  | out_vec: &mut Option<Vec<D>>, | 
|  | ) -> Result<()> { | 
|  | self.borrowed_ref().resize_nullable_out_vec(out_vec) | 
|  | } | 
|  | } | 
|  |  | 
|  | // Internal APIs | 
|  | impl<'a> BorrowedParcel<'a> { | 
|  | pub(crate) fn write_binder(&mut self, binder: Option<&SpIBinder>) -> Result<()> { | 
|  | unsafe { | 
|  | // Safety: `BorrowedParcel` always contains a valid pointer to an | 
|  | // `AParcel`. `AsNative` for `Option<SpIBinder`> will either return | 
|  | // null or a valid pointer to an `AIBinder`, both of which are | 
|  | // valid, safe inputs to `AParcel_writeStrongBinder`. | 
|  | // | 
|  | // This call does not take ownership of the binder. However, it does | 
|  | // require a mutable pointer, which we cannot extract from an | 
|  | // immutable reference, so we clone the binder, incrementing the | 
|  | // refcount before the call. The refcount will be immediately | 
|  | // decremented when this temporary is dropped. | 
|  | status_result(sys::AParcel_writeStrongBinder( | 
|  | self.as_native_mut(), | 
|  | binder.cloned().as_native_mut(), | 
|  | )) | 
|  | } | 
|  | } | 
|  |  | 
|  | pub(crate) fn read_binder(&self) -> Result<Option<SpIBinder>> { | 
|  | let mut binder = ptr::null_mut(); | 
|  | let status = unsafe { | 
|  | // Safety: `BorrowedParcel` always contains a valid pointer to an | 
|  | // `AParcel`. We pass a valid, mutable out pointer to the `binder` | 
|  | // parameter. After this call, `binder` will be either null or a | 
|  | // valid pointer to an `AIBinder` owned by the caller. | 
|  | sys::AParcel_readStrongBinder(self.as_native(), &mut binder) | 
|  | }; | 
|  |  | 
|  | status_result(status)?; | 
|  |  | 
|  | Ok(unsafe { | 
|  | // Safety: `binder` is either null or a valid, owned pointer at this | 
|  | // point, so can be safely passed to `SpIBinder::from_raw`. | 
|  | SpIBinder::from_raw(binder) | 
|  | }) | 
|  | } | 
|  | } | 
|  |  | 
|  | impl Drop for Parcel { | 
|  | fn drop(&mut self) { | 
|  | // Run the C++ Parcel complete object destructor | 
|  | unsafe { | 
|  | // Safety: `Parcel` always contains a valid pointer to an | 
|  | // `AParcel`. Since we own the parcel, we can safely delete it | 
|  | // here. | 
|  | sys::AParcel_delete(self.ptr.as_ptr()) | 
|  | } | 
|  | } | 
|  | } | 
|  |  | 
|  | impl fmt::Debug for Parcel { | 
|  | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | 
|  | f.debug_struct("Parcel") | 
|  | .finish() | 
|  | } | 
|  | } | 
|  |  | 
|  | impl<'a> fmt::Debug for BorrowedParcel<'a> { | 
|  | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { | 
|  | f.debug_struct("BorrowedParcel") | 
|  | .finish() | 
|  | } | 
|  | } | 
|  |  | 
|  | #[test] | 
|  | fn test_read_write() { | 
|  | let mut parcel = Parcel::new(); | 
|  | let start = parcel.get_data_position(); | 
|  |  | 
|  | assert_eq!(parcel.read::<bool>(), Err(StatusCode::NOT_ENOUGH_DATA)); | 
|  | assert_eq!(parcel.read::<i8>(), Err(StatusCode::NOT_ENOUGH_DATA)); | 
|  | assert_eq!(parcel.read::<u16>(), Err(StatusCode::NOT_ENOUGH_DATA)); | 
|  | assert_eq!(parcel.read::<i32>(), Err(StatusCode::NOT_ENOUGH_DATA)); | 
|  | assert_eq!(parcel.read::<u32>(), Err(StatusCode::NOT_ENOUGH_DATA)); | 
|  | assert_eq!(parcel.read::<i64>(), Err(StatusCode::NOT_ENOUGH_DATA)); | 
|  | assert_eq!(parcel.read::<u64>(), Err(StatusCode::NOT_ENOUGH_DATA)); | 
|  | assert_eq!(parcel.read::<f32>(), Err(StatusCode::NOT_ENOUGH_DATA)); | 
|  | assert_eq!(parcel.read::<f64>(), Err(StatusCode::NOT_ENOUGH_DATA)); | 
|  | assert_eq!(parcel.read::<Option<String>>(), Ok(None)); | 
|  | assert_eq!(parcel.read::<String>(), Err(StatusCode::UNEXPECTED_NULL)); | 
|  |  | 
|  | assert_eq!(parcel.borrowed_ref().read_binder().err(), Some(StatusCode::BAD_TYPE)); | 
|  |  | 
|  | parcel.write(&1i32).unwrap(); | 
|  |  | 
|  | unsafe { | 
|  | parcel.set_data_position(start).unwrap(); | 
|  | } | 
|  |  | 
|  | let i: i32 = parcel.read().unwrap(); | 
|  | assert_eq!(i, 1i32); | 
|  | } | 
|  |  | 
|  | #[test] | 
|  | #[allow(clippy::float_cmp)] | 
|  | fn test_read_data() { | 
|  | let mut parcel = Parcel::new(); | 
|  | let str_start = parcel.get_data_position(); | 
|  |  | 
|  | parcel.write(&b"Hello, Binder!\0"[..]).unwrap(); | 
|  | // Skip over string length | 
|  | unsafe { | 
|  | assert!(parcel.set_data_position(str_start).is_ok()); | 
|  | } | 
|  | assert_eq!(parcel.read::<i32>().unwrap(), 15); | 
|  | let start = parcel.get_data_position(); | 
|  |  | 
|  | assert!(parcel.read::<bool>().unwrap()); | 
|  |  | 
|  | unsafe { | 
|  | assert!(parcel.set_data_position(start).is_ok()); | 
|  | } | 
|  |  | 
|  | assert_eq!(parcel.read::<i8>().unwrap(), 72i8); | 
|  |  | 
|  | unsafe { | 
|  | assert!(parcel.set_data_position(start).is_ok()); | 
|  | } | 
|  |  | 
|  | assert_eq!(parcel.read::<u16>().unwrap(), 25928); | 
|  |  | 
|  | unsafe { | 
|  | assert!(parcel.set_data_position(start).is_ok()); | 
|  | } | 
|  |  | 
|  | assert_eq!(parcel.read::<i32>().unwrap(), 1819043144); | 
|  |  | 
|  | unsafe { | 
|  | assert!(parcel.set_data_position(start).is_ok()); | 
|  | } | 
|  |  | 
|  | assert_eq!(parcel.read::<u32>().unwrap(), 1819043144); | 
|  |  | 
|  | unsafe { | 
|  | assert!(parcel.set_data_position(start).is_ok()); | 
|  | } | 
|  |  | 
|  | assert_eq!(parcel.read::<i64>().unwrap(), 4764857262830019912); | 
|  |  | 
|  | unsafe { | 
|  | assert!(parcel.set_data_position(start).is_ok()); | 
|  | } | 
|  |  | 
|  | assert_eq!(parcel.read::<u64>().unwrap(), 4764857262830019912); | 
|  |  | 
|  | unsafe { | 
|  | assert!(parcel.set_data_position(start).is_ok()); | 
|  | } | 
|  |  | 
|  | assert_eq!( | 
|  | parcel.read::<f32>().unwrap(), | 
|  | 1143139100000000000000000000.0 | 
|  | ); | 
|  | assert_eq!(parcel.read::<f32>().unwrap(), 40.043392); | 
|  |  | 
|  | unsafe { | 
|  | assert!(parcel.set_data_position(start).is_ok()); | 
|  | } | 
|  |  | 
|  | assert_eq!(parcel.read::<f64>().unwrap(), 34732488246.197815); | 
|  |  | 
|  | // Skip back to before the string length | 
|  | unsafe { | 
|  | assert!(parcel.set_data_position(str_start).is_ok()); | 
|  | } | 
|  |  | 
|  | assert_eq!(parcel.read::<Vec<u8>>().unwrap(), b"Hello, Binder!\0"); | 
|  | } | 
|  |  | 
|  | #[test] | 
|  | fn test_utf8_utf16_conversions() { | 
|  | let mut parcel = Parcel::new(); | 
|  | let start = parcel.get_data_position(); | 
|  |  | 
|  | assert!(parcel.write("Hello, Binder!").is_ok()); | 
|  | unsafe { | 
|  | assert!(parcel.set_data_position(start).is_ok()); | 
|  | } | 
|  | assert_eq!( | 
|  | parcel.read::<Option<String>>().unwrap().unwrap(), | 
|  | "Hello, Binder!", | 
|  | ); | 
|  | unsafe { | 
|  | assert!(parcel.set_data_position(start).is_ok()); | 
|  | } | 
|  |  | 
|  | assert!(parcel.write("Embedded null \0 inside a string").is_ok()); | 
|  | unsafe { | 
|  | assert!(parcel.set_data_position(start).is_ok()); | 
|  | } | 
|  | assert_eq!( | 
|  | parcel.read::<Option<String>>().unwrap().unwrap(), | 
|  | "Embedded null \0 inside a string", | 
|  | ); | 
|  | unsafe { | 
|  | assert!(parcel.set_data_position(start).is_ok()); | 
|  | } | 
|  |  | 
|  | assert!(parcel.write(&["str1", "str2", "str3"][..]).is_ok()); | 
|  | assert!(parcel | 
|  | .write( | 
|  | &[ | 
|  | String::from("str4"), | 
|  | String::from("str5"), | 
|  | String::from("str6"), | 
|  | ][..] | 
|  | ) | 
|  | .is_ok()); | 
|  |  | 
|  | let s1 = "Hello, Binder!"; | 
|  | let s2 = "This is a utf8 string."; | 
|  | let s3 = "Some more text here."; | 
|  |  | 
|  | assert!(parcel.write(&[s1, s2, s3][..]).is_ok()); | 
|  | unsafe { | 
|  | assert!(parcel.set_data_position(start).is_ok()); | 
|  | } | 
|  |  | 
|  | assert_eq!( | 
|  | parcel.read::<Vec<String>>().unwrap(), | 
|  | ["str1", "str2", "str3"] | 
|  | ); | 
|  | assert_eq!( | 
|  | parcel.read::<Vec<String>>().unwrap(), | 
|  | ["str4", "str5", "str6"] | 
|  | ); | 
|  | assert_eq!(parcel.read::<Vec<String>>().unwrap(), [s1, s2, s3]); | 
|  | } | 
|  |  | 
|  | #[test] | 
|  | fn test_sized_write() { | 
|  | let mut parcel = Parcel::new(); | 
|  | let start = parcel.get_data_position(); | 
|  |  | 
|  | let arr = [1i32, 2i32, 3i32]; | 
|  |  | 
|  | parcel.sized_write(|subparcel| { | 
|  | subparcel.write(&arr[..]) | 
|  | }).expect("Could not perform sized write"); | 
|  |  | 
|  | // i32 sub-parcel length + i32 array length + 3 i32 elements | 
|  | let expected_len = 20i32; | 
|  |  | 
|  | assert_eq!(parcel.get_data_position(), start + expected_len); | 
|  |  | 
|  | unsafe { | 
|  | parcel.set_data_position(start).unwrap(); | 
|  | } | 
|  |  | 
|  | assert_eq!( | 
|  | expected_len, | 
|  | parcel.read().unwrap(), | 
|  | ); | 
|  |  | 
|  | assert_eq!( | 
|  | parcel.read::<Vec<i32>>().unwrap(), | 
|  | &arr, | 
|  | ); | 
|  | } | 
|  |  | 
|  | #[test] | 
|  | fn test_append_from() { | 
|  | let mut parcel1 = Parcel::new(); | 
|  | parcel1.write(&42i32).expect("Could not perform write"); | 
|  |  | 
|  | let mut parcel2 = Parcel::new(); | 
|  | assert_eq!(Ok(()), parcel2.append_all_from(&parcel1)); | 
|  | assert_eq!(4, parcel2.get_data_size()); | 
|  | assert_eq!(Ok(()), parcel2.append_all_from(&parcel1)); | 
|  | assert_eq!(8, parcel2.get_data_size()); | 
|  | unsafe { | 
|  | parcel2.set_data_position(0).unwrap(); | 
|  | } | 
|  | assert_eq!(Ok(42), parcel2.read::<i32>()); | 
|  | assert_eq!(Ok(42), parcel2.read::<i32>()); | 
|  |  | 
|  | let mut parcel2 = Parcel::new(); | 
|  | assert_eq!(Ok(()), parcel2.append_from(&parcel1, 0, 2)); | 
|  | assert_eq!(Ok(()), parcel2.append_from(&parcel1, 2, 2)); | 
|  | assert_eq!(4, parcel2.get_data_size()); | 
|  | unsafe { | 
|  | parcel2.set_data_position(0).unwrap(); | 
|  | } | 
|  | assert_eq!(Ok(42), parcel2.read::<i32>()); | 
|  |  | 
|  | let mut parcel2 = Parcel::new(); | 
|  | assert_eq!(Ok(()), parcel2.append_from(&parcel1, 0, 2)); | 
|  | assert_eq!(2, parcel2.get_data_size()); | 
|  | unsafe { | 
|  | parcel2.set_data_position(0).unwrap(); | 
|  | } | 
|  | assert_eq!(Err(StatusCode::NOT_ENOUGH_DATA), parcel2.read::<i32>()); | 
|  |  | 
|  | let mut parcel2 = Parcel::new(); | 
|  | assert_eq!(Err(StatusCode::BAD_VALUE), parcel2.append_from(&parcel1, 4, 2)); | 
|  | assert_eq!(Err(StatusCode::BAD_VALUE), parcel2.append_from(&parcel1, 2, 4)); | 
|  | assert_eq!(Err(StatusCode::BAD_VALUE), parcel2.append_from(&parcel1, -1, 4)); | 
|  | assert_eq!(Err(StatusCode::BAD_VALUE), parcel2.append_from(&parcel1, 2, -1)); | 
|  | } |