WIP: api-level bindings

ndk-sys/generate_bindings.sh

@@ -30,6 +30,7 @@ while read ARCH && read TARGET ; do
         --blocklist-item 'C?_?JNIEnv' \
         --blocklist-item '_?JavaVM' \
         --blocklist-item '_?j\w+' \
+        --blocklist-item '__ANDROID_API__' \
         --newtype-enum '\w+_(result|status)_t' \
         --newtype-enum 'ACameraDevice_request_template' \
         --newtype-enum 'ADataSpace' \

ndk/src/api_level.rs

@@ -0,0 +1,154 @@
+//! `__ANDROID_API__` is the [API
+//! level](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
+//! this code is being built for. The resulting binaries are only guaranteed to
+//! be compatible with devices which have an API level greater than or equal to
+//! `__ANDROID_API__`.
+//!
+//! For NDK and APEX builds, this macro will always be defined. It is set
+//! automatically by Clang using the version suffix that is a part of the target
+//! name. For example, `__ANDROID_API__` will be 24 when Clang is given the
+//! argument `-target aarch64-linux-android24`.
+//!
+//! For non-APEX OS code, this defaults to  __ANDROID_API_FUTURE__.
+//!
+//! The value of `__ANDROID_API__` can be compared to the named constants in
+//! `<android/api-level.h>`.
+//!
+//! The interpretation of `__ANDROID_API__` is similar to the AndroidManifest.xml
+//! `minSdkVersion`. In most cases `__ANDROID_API__` will be identical to
+//! `minSdkVersion`, but as it is a build time constant it is possible for
+//! library code to use a different value than the app it will be included in.
+//! When libraries and applications build for different API levels, the
+//! `minSdkVersion` of the application must be at least as high as the highest
+//! API level used by any of its libraries which are loaded unconditionally.
+//!
+//! Note that in some cases the resulting binaries may load successfully on
+//! devices with an older API level. That behavior should not be relied upon,
+//! even if you are careful to avoid using new APIs, as the toolchain may make
+//! use of new features by default. For example, additional FORTIFY features may
+//! implicitly make use of new APIs, SysV hashes may be omitted in favor of GNU
+//! hashes to improve library load times, or relocation packing may be enabled to
+//! reduce binary size.
+//!
+//! See android_get_device_api_level(),
+//! android_get_application_target_sdk_version() and
+//! https://android.googlesource.com/platform/bionic/+/master/docs/defines.md.
+
+use num_enum::{FromPrimitive, IntoPrimitive};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, FromPrimitive, IntoPrimitive)]
+#[repr(u32)]
+#[non_exhaustive]
+pub enum ApiLevel {
+    /** Names the Gingerbread API level (9) */
+    G = ffi::__ANDROID_API_G__,
+
+    /** Names the Ice-Cream Sandwich API level (14) */
+    I = ffi::__ANDROID_API_I__,
+
+    /** Names the Jellybean API level (16) */
+    J = ffi::__ANDROID_API_J__,
+
+    /** Names the Jellybean MR1 API level (17) */
+    J_MR1 = ffi::__ANDROID_API_J_MR1__,
+
+    /** Names the Jellybean MR2 API level (18) */
+    J_MR2 = ffi::__ANDROID_API_J_MR2__,
+
+    /** Names the KitKat API level (19) */
+    K = ffi::__ANDROID_API_K__,
+
+    /** Names the Lollipop API level (21) */
+    L = ffi::__ANDROID_API_L__,
+
+    /** Names the Lollipop MR1 API level (22) */
+    L_MR1 = ffi::__ANDROID_API_L_MR1__,
+
+    /** Names the Marshmallow API level (23) */
+    M = ffi::__ANDROID_API_M__,
+
+    /** Names the Nougat API level (24) */
+    N = ffi::__ANDROID_API_N__,
+
+    /** Names the Nougat MR1 API level (25) */
+    N_MR1 = ffi::__ANDROID_API_N_MR1__,
+
+    /** Names the Oreo API level (26) */
+    O = ffi::__ANDROID_API_O__,
+
+    /** Names the Oreo MR1 API level (27) */
+    O_MR1 = ffi::__ANDROID_API_O_MR1__,
+
+    /** Names the Pie API level (28) */
+    P = ffi::__ANDROID_API_P__,
+
+    /** Names the Android 10 (aka "Q" or "Quince Tart") API level (29) */
+    Q = ffi::__ANDROID_API_Q__,
+
+    /** Names the Android 11 (aka "R" or "Red Velvet Cake") API level (30) */
+    R = ffi::__ANDROID_API_R__,
+
+    /** Names the Android 12 (aka "S" or "Snowcone") API level (31) */
+    S = ffi::__ANDROID_API_S__,
+
+    /** Names the Android 13 (aka "T" or "Tiramisu") API level (33) */
+    T = ffi::__ANDROID_API_T__,
+
+    /** Names the Android 14 (aka "U" or "UpsideDownCake") API level (34) */
+    U = ffi::__ANDROID_API_U__,
+
+    /** Names the "V" API level (35) */
+    V = ffi::__ANDROID_API_V__,
+
+    #[doc(hidden)]
+    #[num_enum(catch_all)]
+    __Unknown(u32),
+}
+
+/// Returns the `targetSdkVersion` of the caller, or [`ffi::__ANDROID_API_FUTURE__`] if there is no
+/// known target SDK version (for code not running in the context of an app).
+///
+/// The returned values correspond to the named constants in `<android/api-level.h>`, and is
+/// equivalent to the `AndroidManifest.xml` `targetSdkVersion`.
+///
+/// See also [`device_api_level()`].
+#[cfg(feature = "api-level-24")]
+pub fn application_target_sdk_version() -> i32 {
+    #[cfg(feature = "api-level-29")]
+    unsafe {
+        ffi::android_get_application_target_sdk_version()
+    }
+
+    #[cfg(not(feature = "api-level-29"))]
+    {
+        use std::ffi::{c_char, c_int};
+        let mut value = [0; 92];
+        if unsafe {
+            // TODO: from sys/cdefs.h, available in libc
+            extern "C" {
+                fn __system_property_get(__name: *const c_char, __value: *mut c_char) -> c_int;
+            }
+            // libc::
+            __system_property_get(c"ro.build.version.sdk".as_ptr(), value.as_mut_ptr())
+        } < 1
+        {
+            -1
+        } else {
+            std::str::from_utf8(&value)
+                .unwrap_or("")
+                .parse()
+                .unwrap_or(-1)
+            // TODO: Return -1 if this is 0?
+        }
+    }
+}
+
+/// Returns the API level of the device we're actually running on, or `-1` on failure. The returned
+/// values correspond to the named constants in `<android/api-level.h>`, and is equivalent to the
+/// Java `Build.VERSION.SDK_INT` API.
+///
+/// See also [`application_target_sdk_version()`].
+#[cfg(feature = "api-level-29")]
+pub fn device_api_level() -> i32 {
+    unsafe { ffi::android_get_device_api_level() }
+}

ndk/src/lib.rs

@@ -11,6 +11,7 @@
 )]
 #![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
 
+pub mod api_level;
 pub mod asset;
 pub mod audio;
 pub mod bitmap;