Merge "Wrap AHardwareBuffer_LockPlanes too." into main

    StatusCode,

};

use ffi::{

    AHardwareBuffer, AHardwareBuffer_Desc, AHardwareBuffer_readFromParcel,

    AHardwareBuffer_writeToParcel, ARect,

    AHardwareBuffer, AHardwareBuffer_Desc, AHardwareBuffer_Plane, AHardwareBuffer_Planes,

    AHardwareBuffer_readFromParcel, AHardwareBuffer_writeToParcel, ARect,

};

use std::ffi::c_void;

use std::fmt::{self, Debug, Formatter};

        })

    }

    /// Lock a potentially multi-planar hardware buffer for direct CPU access.

    ///

    /// # Safety

    ///

    /// - If `fence` is `None`, the caller must ensure that all writes to the buffer have completed

    ///   before calling this function.

    /// - If the buffer has `AHARDWAREBUFFER_FORMAT_BLOB`, multiple threads or process may lock the

    ///   buffer simultaneously, but the caller must ensure that they don't access it simultaneously

    ///   and break Rust's aliasing rules, like any other shared memory.

    /// - Otherwise if `usage` includes `AHARDWAREBUFFER_USAGE_CPU_WRITE_RARELY` or

    ///   `AHARDWAREBUFFER_USAGE_CPU_WRITE_OFTEN`, the caller must ensure that no other threads or

    ///   processes lock the buffer simultaneously for any usage.

    /// - Otherwise, the caller must ensure that no other threads lock the buffer for writing

    ///   simultaneously.

    /// - If `rect` is not `None`, the caller must not modify the buffer outside of that rectangle.

    pub unsafe fn lock_planes<'a>(

        &'a self,

        usage: AHardwareBuffer_UsageFlags,

        fence: Option<BorrowedFd>,

        rect: Option<&ARect>,

    ) -> Result<Vec<PlaneGuard<'a>>, StatusCode> {

        let fence = if let Some(fence) = fence { fence.as_raw_fd() } else { -1 };

        let rect = rect.map(ptr::from_ref).unwrap_or(null());

        let mut planes = AHardwareBuffer_Planes {

            planeCount: 0,

            planes: [const { AHardwareBuffer_Plane { data: null_mut(), pixelStride: 0, rowStride: 0 } };

                4],

        };

        // SAFETY: The `AHardwareBuffer` pointer we wrap is always valid, and the various out

        // pointers are valid because they come from references. Our caller promises that writes have

        // completed and there will be no simultaneous read/write locks.

        let status = unsafe {

            ffi::AHardwareBuffer_lockPlanes(self.0.as_ptr(), usage.0, fence, rect, &mut planes)

        };

        status_result(status)?;

        let plane_count = planes.planeCount.try_into().unwrap();

        Ok(planes.planes[..plane_count]

            .iter()

            .map(|plane| PlaneGuard {

                guard: HardwareBufferGuard {

                    buffer: self,

                    address: NonNull::new(plane.data)

                        .expect("AHardwareBuffer_lockAndGetInfo set a null outVirtualAddress"),

                },

                pixel_stride: plane.pixelStride,

                row_stride: plane.rowStride,

            })

            .collect())

    }

    /// Locks the hardware buffer for direct CPU access, returning information about the bytes per

    /// pixel and stride as well.

    ///

    pub stride: u32,

}

/// A guard for a single plane of a locked `HardwareBuffer`, with additional information about the

/// stride.

#[derive(Debug)]

pub struct PlaneGuard<'a> {

    /// The locked buffer guard.

    pub guard: HardwareBufferGuard<'a>,

    /// The stride in bytes between the color channel for one pixel to the next pixel.

    pub pixel_stride: u32,

    /// The stride in bytes between rows in the buffer.

    pub row_stride: u32,

}

#[cfg(test)]

mod test {

    use super::*;