| /* |
| * Copyright (C) 2015 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. |
| */ |
| |
| #ifndef ANDROID_HARDWARE_BINDER_STATUS_H |
| #define ANDROID_HARDWARE_BINDER_STATUS_H |
| |
| #include <cstdint> |
| #include <sstream> |
| |
| #include <hidl/HidlInternal.h> |
| #include <utils/Errors.h> |
| #include <utils/StrongPointer.h> |
| |
| namespace android { |
| namespace hardware { |
| |
| // An object similar in function to a status_t except that it understands |
| // how exceptions are encoded in the prefix of a Parcel. Used like: |
| // |
| // Parcel data; |
| // Parcel reply; |
| // status_t status; |
| // binder::Status remote_exception; |
| // if ((status = data.writeInterfaceToken(interface_descriptor)) != OK || |
| // (status = data.writeInt32(function_input)) != OK) { |
| // // We failed to write into the memory of our local parcel? |
| // } |
| // if ((status = remote()->transact(transaction, data, &reply)) != OK) { |
| // // Something has gone wrong in the binder driver or libbinder. |
| // } |
| // if ((status = remote_exception.readFromParcel(reply)) != OK) { |
| // // The remote didn't correctly write the exception header to the |
| // // reply. |
| // } |
| // if (!remote_exception.isOk()) { |
| // // The transaction went through correctly, but the remote reported an |
| // // exception during handling. |
| // } |
| // |
| class Status final { |
| public: |
| // Keep the exception codes in sync with android/os/Parcel.java. |
| enum Exception { |
| EX_NONE = 0, |
| EX_SECURITY = -1, |
| EX_BAD_PARCELABLE = -2, |
| EX_ILLEGAL_ARGUMENT = -3, |
| EX_NULL_POINTER = -4, |
| EX_ILLEGAL_STATE = -5, |
| EX_NETWORK_MAIN_THREAD = -6, |
| EX_UNSUPPORTED_OPERATION = -7, |
| |
| // This is special and Java specific; see Parcel.java. |
| EX_HAS_REPLY_HEADER = -128, |
| // This is special, and indicates to C++ binder proxies that the |
| // transaction has failed at a low level. |
| EX_TRANSACTION_FAILED = -129, |
| }; |
| |
| // A more readable alias for the default constructor. |
| static Status ok(); |
| // Authors should explicitly pick whether their integer is: |
| // - an exception code (EX_* above) |
| // - status_t |
| // |
| // Prefer a generic exception code when possible or a status_t |
| // for low level transport errors. Service specific errors |
| // should be at a higher level in HIDL. |
| static Status fromExceptionCode(int32_t exceptionCode); |
| static Status fromExceptionCode(int32_t exceptionCode, |
| const char *message); |
| static Status fromStatusT(status_t status); |
| |
| Status() = default; |
| ~Status() = default; |
| |
| // Status objects are copyable and contain just simple data. |
| Status(const Status& status) = default; |
| Status(Status&& status) = default; |
| Status& operator=(const Status& status) = default; |
| |
| // Set one of the pre-defined exception types defined above. |
| void setException(int32_t ex, const char *message); |
| // Setting a |status| != OK causes generated code to return |status| |
| // from Binder transactions, rather than writing an exception into the |
| // reply Parcel. This is the least preferable way of reporting errors. |
| void setFromStatusT(status_t status); |
| |
| // Get information about an exception. |
| int32_t exceptionCode() const { return mException; } |
| const char *exceptionMessage() const { return mMessage.c_str(); } |
| status_t transactionError() const { |
| return mException == EX_TRANSACTION_FAILED ? mErrorCode : OK; |
| } |
| |
| bool isOk() const { return mException == EX_NONE; } |
| |
| // For debugging purposes only |
| std::string description() const; |
| |
| private: |
| Status(int32_t exceptionCode, int32_t errorCode); |
| Status(int32_t exceptionCode, int32_t errorCode, const char *message); |
| |
| // If |mException| == EX_TRANSACTION_FAILED, generated code will return |
| // |mErrorCode| as the result of the transaction rather than write an |
| // exception to the reply parcel. |
| // |
| // Otherwise, we always write |mException| to the parcel. |
| // If |mException| != EX_NONE, we write |mMessage| as well. |
| int32_t mException = EX_NONE; |
| int32_t mErrorCode = 0; |
| std::string mMessage; |
| }; // class Status |
| |
| // For gtest output logging |
| std::ostream& operator<< (std::ostream& stream, const Status& s); |
| |
| template<typename T> class Return; |
| |
| namespace details { |
| class return_status { |
| private: |
| Status mStatus {}; |
| mutable bool mCheckedStatus = false; |
| |
| template <typename T, typename U> |
| friend Return<U> StatusOf(const Return<T> &other); |
| protected: |
| void assertOk() const; |
| public: |
| return_status() {} |
| return_status(Status s) : mStatus(s) {} |
| |
| return_status(const return_status &) = delete; |
| return_status &operator=(const return_status &) = delete; |
| |
| return_status(return_status &&other) { |
| *this = std::move(other); |
| } |
| return_status &operator=(return_status &&other); |
| |
| ~return_status(); |
| |
| bool isOk() const { |
| mCheckedStatus = true; |
| return mStatus.isOk(); |
| } |
| |
| // Check if underlying error is DEAD_OBJECT. |
| // Check mCheckedStatus only if this method returns true. |
| bool isDeadObject() const { |
| bool dead = mStatus.transactionError() == DEAD_OBJECT; |
| |
| // This way, if you only check isDeadObject your process will |
| // only be killed for more serious unchecked errors |
| if (dead) { |
| mCheckedStatus = true; |
| } |
| |
| return dead; |
| } |
| |
| // For debugging purposes only |
| std::string description() const { |
| // Doesn't consider checked. |
| return mStatus.description(); |
| } |
| }; |
| } // namespace details |
| |
| template<typename T> class Return : public details::return_status { |
| private: |
| T mVal {}; |
| public: |
| Return(T v) : details::return_status(), mVal{v} {} |
| Return(Status s) : details::return_status(s) {} |
| |
| // move-able. |
| // precondition: "this" has checked status |
| // postcondition: other is safe to destroy after moving to *this. |
| Return(Return &&other) = default; |
| Return &operator=(Return &&) = default; |
| |
| ~Return() = default; |
| |
| operator T() const { |
| assertOk(); |
| return mVal; |
| } |
| |
| T withDefault(T t) { |
| return isOk() ? mVal : t; |
| } |
| }; |
| |
| template<typename T> class Return<sp<T>> : public details::return_status { |
| private: |
| sp<T> mVal {}; |
| public: |
| Return(sp<T> v) : details::return_status(), mVal{v} {} |
| Return(T* v) : details::return_status(), mVal{v} {} |
| // Constructors matching a different type (that is related by inheritance) |
| template<typename U> Return(sp<U> v) : details::return_status(), mVal{v} {} |
| template<typename U> Return(U* v) : details::return_status(), mVal{v} {} |
| Return(Status s) : details::return_status(s) {} |
| |
| // move-able. |
| // precondition: "this" has checked status |
| // postcondition: other is safe to destroy after moving to *this. |
| Return(Return &&other) = default; |
| Return &operator=(Return &&) = default; |
| |
| ~Return() = default; |
| |
| operator sp<T>() const { |
| assertOk(); |
| return mVal; |
| } |
| |
| sp<T> withDefault(sp<T> t) { |
| return isOk() ? mVal : t; |
| } |
| }; |
| |
| |
| template<> class Return<void> : public details::return_status { |
| public: |
| Return() : details::return_status() {} |
| Return(Status s) : details::return_status(s) {} |
| |
| // move-able. |
| // precondition: "this" has checked status |
| // postcondition: other is safe to destroy after moving to *this. |
| Return(Return &&) = default; |
| Return &operator=(Return &&) = default; |
| |
| ~Return() = default; |
| }; |
| |
| static inline Return<void> Void() { |
| return Return<void>(); |
| } |
| |
| namespace details { |
| // Create a Return<U> from the Status of Return<T>. The provided |
| // Return<T> must have an error status and have it checked. |
| template <typename T, typename U> |
| Return<U> StatusOf(const Return<T> &other) { |
| if (other.mStatus.isOk() || !other.mCheckedStatus) { |
| details::logAlwaysFatal("cannot call statusOf on an OK Status or an unchecked status"); |
| } |
| return Return<U>{other.mStatus}; |
| } |
| } // namespace details |
| |
| } // namespace hardware |
| } // namespace android |
| |
| #endif // ANDROID_HARDWARE_BINDER_STATUS_H |