Add methods to get vectors.

Bug: 389074518
Test: atest libbinder_rs-internal_test
Change-Id: Id26f265e6f3bea4a0149e28fa7dba6092b958dda

Author: qwandor

libs/binder/rust/src/persistable_bundle.rs

@@ -22,17 +22,18 @@ use crate::{
 };
 use binder_ndk_sys::{
     APersistableBundle, APersistableBundle_delete, APersistableBundle_dup,
-    APersistableBundle_erase, APersistableBundle_getBoolean, APersistableBundle_getDouble,
-    APersistableBundle_getInt, APersistableBundle_getLong, APersistableBundle_getPersistableBundle,
-    APersistableBundle_isEqual, APersistableBundle_new, APersistableBundle_putBoolean,
-    APersistableBundle_putBooleanVector, APersistableBundle_putDouble,
-    APersistableBundle_putDoubleVector, APersistableBundle_putInt, APersistableBundle_putIntVector,
-    APersistableBundle_putLong, APersistableBundle_putLongVector,
+    APersistableBundle_erase, APersistableBundle_getBoolean, APersistableBundle_getBooleanVector,
+    APersistableBundle_getDouble, APersistableBundle_getDoubleVector, APersistableBundle_getInt,
+    APersistableBundle_getIntVector, APersistableBundle_getLong, APersistableBundle_getLongVector,
+    APersistableBundle_getPersistableBundle, APersistableBundle_isEqual, APersistableBundle_new,
+    APersistableBundle_putBoolean, APersistableBundle_putBooleanVector,
+    APersistableBundle_putDouble, APersistableBundle_putDoubleVector, APersistableBundle_putInt,
+    APersistableBundle_putIntVector, APersistableBundle_putLong, APersistableBundle_putLongVector,
     APersistableBundle_putPersistableBundle, APersistableBundle_putString,
     APersistableBundle_putStringVector, APersistableBundle_readFromParcel, APersistableBundle_size,
-    APersistableBundle_writeToParcel,
+    APersistableBundle_writeToParcel, APERSISTABLEBUNDLE_KEY_NOT_FOUND,
 };
-use std::ffi::{CString, NulError};
+use std::ffi::{c_char, CString, NulError};
 use std::ptr::{null_mut, NonNull};
 
 /// A mapping from string keys to values of various types.
@@ -373,6 +374,104 @@ impl PersistableBundle {
         }
     }
 
+    /// Gets the vector of `T` associated with the given key.
+    ///
+    /// Returns an error if the key contains a NUL character, or `Ok(None)` if the key doesn't exist
+    /// in the bundle.
+    ///
+    /// `get_func` should be one of the `APersistableBundle_get*Vector` functions from
+    /// `binder_ndk_sys`.
+    ///
+    /// # Safety
+    ///
+    /// `get_func` must only require that the pointers it takes are valid for the duration of the
+    /// call. It must allow a null pointer for the buffer, and must return the size in bytes of
+    /// buffer it requires. If it is given a non-null buffer pointer it must write that number of
+    /// bytes to the buffer, which must be a whole number of valid `T` values.
+    unsafe fn get_vec<T: Clone + Default>(
+        &self,
+        key: &str,
+        get_func: unsafe extern "C" fn(
+            *const APersistableBundle,
+            *const c_char,
+            *mut T,
+            i32,
+        ) -> i32,
+    ) -> Result<Option<Vec<T>>, NulError> {
+        let key = CString::new(key)?;
+        // SAFETY: The wrapped `APersistableBundle` pointer is guaranteed to be valid for the
+        // lifetime of the `PersistableBundle`. The pointer returned by `key.as_ptr()` is guaranteed
+        // to be valid for the lifetime of `key`. A null pointer is allowed for the buffer.
+        match unsafe { get_func(self.0.as_ptr(), key.as_ptr(), null_mut(), 0) } {
+            APERSISTABLEBUNDLE_KEY_NOT_FOUND => Ok(None),
+            required_buffer_size => {
+                let mut value = vec![
+                    T::default();
+                    usize::try_from(required_buffer_size).expect(
+                        "APersistableBundle_get*Vector returned invalid size"
+                    ) / size_of::<T>()
+                ];
+                // SAFETY: The wrapped `APersistableBundle` pointer is guaranteed to be valid for
+                // the lifetime of the `PersistableBundle`. The pointer returned by `key.as_ptr()`
+                // is guaranteed to be valid for the lifetime of `key`. The value buffer pointer is
+                // valid as it comes from the Vec we just allocated.
+                match unsafe {
+                    get_func(
+                        self.0.as_ptr(),
+                        key.as_ptr(),
+                        value.as_mut_ptr(),
+                        (value.len() * size_of::<T>()).try_into().unwrap(),
+                    )
+                } {
+                    APERSISTABLEBUNDLE_KEY_NOT_FOUND => {
+                        panic!("APersistableBundle_get*Vector failed to find key after first finding it");
+                    }
+                    _ => Ok(Some(value)),
+                }
+            }
+        }
+    }
+
+    /// Gets the boolean vector value associated with the given key.
+    ///
+    /// Returns an error if the key contains a NUL character, or `Ok(None)` if the key doesn't exist
+    /// in the bundle.
+    pub fn get_bool_vec(&self, key: &str) -> Result<Option<Vec<bool>>, NulError> {
+        // SAFETY: APersistableBundle_getBooleanVector fulfils all the safety requirements of
+        // `get_vec`.
+        unsafe { self.get_vec(key, APersistableBundle_getBooleanVector) }
+    }
+
+    /// Gets the i32 vector value associated with the given key.
+    ///
+    /// Returns an error if the key contains a NUL character, or `Ok(None)` if the key doesn't exist
+    /// in the bundle.
+    pub fn get_int_vec(&self, key: &str) -> Result<Option<Vec<i32>>, NulError> {
+        // SAFETY: APersistableBundle_getIntVector fulfils all the safety requirements of
+        // `get_vec`.
+        unsafe { self.get_vec(key, APersistableBundle_getIntVector) }
+    }
+
+    /// Gets the i64 vector value associated with the given key.
+    ///
+    /// Returns an error if the key contains a NUL character, or `Ok(None)` if the key doesn't exist
+    /// in the bundle.
+    pub fn get_long_vec(&self, key: &str) -> Result<Option<Vec<i64>>, NulError> {
+        // SAFETY: APersistableBundle_getLongVector fulfils all the safety requirements of
+        // `get_vec`.
+        unsafe { self.get_vec(key, APersistableBundle_getLongVector) }
+    }
+
+    /// Gets the f64 vector value associated with the given key.
+    ///
+    /// Returns an error if the key contains a NUL character, or `Ok(None)` if the key doesn't exist
+    /// in the bundle.
+    pub fn get_double_vec(&self, key: &str) -> Result<Option<Vec<f64>>, NulError> {
+        // SAFETY: APersistableBundle_getDoubleVector fulfils all the safety requirements of
+        // `get_vec`.
+        unsafe { self.get_vec(key, APersistableBundle_getDoubleVector) }
+    }
+
     /// Gets the `PersistableBundle` value associated with the given key.
     ///
     /// Returns an error if the key contains a NUL character, or `Ok(None)` if the key doesn't exist
@@ -486,6 +585,10 @@ mod test {
         assert_eq!(bundle.get_int("foo"), Ok(None));
         assert_eq!(bundle.get_long("foo"), Ok(None));
         assert_eq!(bundle.get_double("foo"), Ok(None));
+        assert_eq!(bundle.get_bool_vec("foo"), Ok(None));
+        assert_eq!(bundle.get_int_vec("foo"), Ok(None));
+        assert_eq!(bundle.get_long_vec("foo"), Ok(None));
+        assert_eq!(bundle.get_double_vec("foo"), Ok(None));
     }
 
     #[test]
@@ -543,7 +646,7 @@ mod test {
     }
 
     #[test]
-    fn insert_vec() {
+    fn insert_get_vec() {
         let mut bundle = PersistableBundle::new();
 
         assert_eq!(bundle.insert_bool_vec("bool", &[]), Ok(()));
@@ -567,6 +670,11 @@ mod test {
         );
 
         assert_eq!(bundle.size(), 5);
+
+        assert_eq!(bundle.get_bool_vec("bool"), Ok(Some(vec![])));
+        assert_eq!(bundle.get_int_vec("int"), Ok(Some(vec![42])));
+        assert_eq!(bundle.get_long_vec("long"), Ok(Some(vec![66, 67, 68])));
+        assert_eq!(bundle.get_double_vec("double"), Ok(Some(vec![123.4])));
     }
 
     #[test]

libs/binder/rust/sys/BinderBindings.hpp

@@ -92,6 +92,11 @@ enum {
 #endif
 };
 
+enum {
+    APERSISTABLEBUNDLE_KEY_NOT_FOUND = APERSISTABLEBUNDLE_KEY_NOT_FOUND,
+    APERSISTABLEBUNDLE_ALLOCATOR_FAILED = APERSISTABLEBUNDLE_ALLOCATOR_FAILED,
+};
+
 } // namespace consts
 
 } // namespace c_interface