1 // Copyright 2024 The Chromium Authors 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef BASE_ANDROID_JNI_BYTEBUFFER_H_ 6 #define BASE_ANDROID_JNI_BYTEBUFFER_H_ 7 8 #include <jni.h> 9 10 #include <optional> 11 12 #include "base/base_export.h" 13 #include "base/containers/span.h" 14 15 namespace base::android { 16 17 // Given a JNIEnv and a jobject representing a byte buffer, produce a base::span 18 // corresponding to that byte buffer. These crash at runtime if the passed-in 19 // jobject does not correspond to a java.nio.Buffer, or if the passed-in buffer 20 // is unaligned and the current CPU architecture may sometimes require aligned 21 // accesses - this requirement is enforced even if your code never actually 22 // *does* the types of accesses that require alignment. 23 // 24 // Usually, that is what you want, since both of those conditions are programmer 25 // errors. 26 // 27 // If needed, there are also variants below starting with Maybe that return 28 // std::nullopt in that case and do not crash. 29 base::span<const uint8_t> BASE_EXPORT JavaByteBufferToSpan(JNIEnv* env, 30 jobject buffer); 31 32 base::span<uint8_t> BASE_EXPORT JavaByteBufferToMutableSpan(JNIEnv* env, 33 jobject buffer); 34 35 std::optional<base::span<const uint8_t>> BASE_EXPORT 36 MaybeJavaByteBufferToSpan(JNIEnv* env, jobject buffer); 37 38 std::optional<base::span<uint8_t>> BASE_EXPORT 39 MaybeJavaByteBufferToMutableSpan(JNIEnv* env, jobject buffer); 40 41 } // namespace base::android 42 43 #endif // BASE_ANDROID_JNI_BYTEBUFFER_H_ 44