1 files changed, 127 insertions, 0 deletions
diff --git a/libs/binder/rust/src/parcel/file_descriptor.rs b/libs/binder/rust/src/parcel/file_descriptor.rs
new file mode 100644
index 0000000000..20e91785d3
--- /dev/null
+++ b/libs/binder/rust/src/parcel/file_descriptor.rs
@@ -0,0 +1,127 @@
+/*
+ * 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.
+ */
+
+use super::{
+    Deserialize, DeserializeArray, DeserializeOption, Parcel, Serialize, SerializeArray,
+    SerializeOption,
+};
+use crate::binder::AsNative;
+use crate::error::{status_result, Result, StatusCode};
+use crate::sys;
+
+use std::fs::File;
+use std::os::unix::io::{AsRawFd, FromRawFd};
+
+/// Rust version of the Java class android.os.ParcelFileDescriptor
+#[derive(Debug)]
+pub struct ParcelFileDescriptor(File);
+
+impl ParcelFileDescriptor {
+    /// Create a new `ParcelFileDescriptor`
+    pub fn new(file: File) -> Self {
+        Self(file)
+    }
+}
+
+impl AsRef<File> for ParcelFileDescriptor {
+    fn as_ref(&self) -> &File {
+        &self.0
+    }
+}
+
+impl From<ParcelFileDescriptor> for File {
+    fn from(file: ParcelFileDescriptor) -> File {
+        file.0
+    }
+}
+
+impl Serialize for ParcelFileDescriptor {
+    fn serialize(&self, parcel: &mut Parcel) -> Result<()> {
+        let fd = self.0.as_raw_fd();
+        let status = unsafe {
+            // Safety: `Parcel` always contains a valid pointer to an
+            // `AParcel`. Likewise, `ParcelFileDescriptor` always contains a
+            // valid file, so we can borrow a valid file
+            // descriptor. `AParcel_writeParcelFileDescriptor` does NOT take
+            // ownership of the fd, so we need not duplicate it first.
+            sys::AParcel_writeParcelFileDescriptor(parcel.as_native_mut(), fd)
+        };
+        status_result(status)
+    }
+}
+
+impl SerializeArray for ParcelFileDescriptor {}
+
+impl SerializeOption for ParcelFileDescriptor {
+    fn serialize_option(this: Option<&Self>, parcel: &mut Parcel) -> Result<()> {
+        if let Some(f) = this {
+            f.serialize(parcel)
+        } else {
+            let status = unsafe {
+                // Safety: `Parcel` always contains a valid pointer to an
+                // `AParcel`. `AParcel_writeParcelFileDescriptor` accepts the
+                // value `-1` as the file descriptor to signify serializing a
+                // null file descriptor.
+                sys::AParcel_writeParcelFileDescriptor(parcel.as_native_mut(), -1i32)
+            };
+            status_result(status)
+        }
+    }
+}
+
+impl SerializeArray for Option<ParcelFileDescriptor> {}
+
+impl DeserializeOption for ParcelFileDescriptor {
+    fn deserialize_option(parcel: &Parcel) -> Result<Option<Self>> {
+        let mut fd = -1i32;
+        unsafe {
+            // Safety: `Parcel` always contains a valid pointer to an
+            // `AParcel`. We pass a valid mutable pointer to an i32, which
+            // `AParcel_readParcelFileDescriptor` assigns the valid file
+            // descriptor into, or `-1` if deserializing a null file
+            // descriptor. The read function passes ownership of the file
+            // descriptor to its caller if it was non-null, so we must take
+            // ownership of the file and ensure that it is eventually closed.
+            status_result(sys::AParcel_readParcelFileDescriptor(
+                parcel.as_native(),
+                &mut fd,
+            ))?;
+        }
+        if fd < 0 {
+            Ok(None)
+        } else {
+            let file = unsafe {
+                // Safety: At this point, we know that the file descriptor was
+                // not -1, so must be a valid, owned file descriptor which we
+                // can safely turn into a `File`.
+                File::from_raw_fd(fd)
+            };
+            Ok(Some(ParcelFileDescriptor::new(file)))
+        }
+    }
+}
+
+impl DeserializeArray for Option<ParcelFileDescriptor> {}
+
+impl Deserialize for ParcelFileDescriptor {
+    fn deserialize(parcel: &Parcel) -> Result<Self> {
+        Deserialize::deserialize(parcel)
+            .transpose()
+            .unwrap_or(Err(StatusCode::UNEXPECTED_NULL))
+    }
+}
+
+impl DeserializeArray for ParcelFileDescriptor {}