Merge changes from topic "libbinder_ndk_aidl"

* changes:
  libbinder_ndk: Add C++ wrapper code.
  libbinder_ndk: add read/write string methods.

7 files changed, 543 insertions, 0 deletions

diff --git a/libs/binder/ndk/include_ndk/android/binder_auto_utils.h b/libs/binder/ndk/include_ndk/android/binder_auto_utils.h
new file mode 100644
index 0000000000..11b1e8eaf5
--- /dev/null
+++ b/libs/binder/ndk/include_ndk/android/binder_auto_utils.h
@@ -0,0 +1,234 @@
+/*
+ * Copyright (C) 2018 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.
+ */
+
+/**
+ * @addtogroup NdkBinder
+ * @{
+ */
+
+/**
+ * @file binder_auto_utils.h
+ * @brief These objects provide a more C++-like thin interface to the .
+ */
+
+#pragma once
+
+#include <android/binder_ibinder.h>
+#include <android/binder_parcel.h>
+#include <android/binder_status.h>
+
+#ifdef __cplusplus
+
+#include <cstddef>
+
+namespace android {
+
+/**
+ * Represents one strong pointer to an AIBinder object.
+ */
+class AutoAIBinder {
+public:
+    /**
+     * Takes ownership of one strong refcount of binder.
+     */
+    explicit AutoAIBinder(AIBinder* binder = nullptr) : mBinder(binder) {}
+
+    /**
+     * Convenience operator for implicitly constructing an AutoAIBinder from nullptr. This is not
+     * explicit because it is not taking ownership of anything.
+     */
+    AutoAIBinder(std::nullptr_t) : AutoAIBinder() {}
+
+    /**
+     * This will delete the underlying object if it exists. See operator=.
+     */
+    AutoAIBinder(const AutoAIBinder& other) { *this = other; }
+
+    /**
+     * This deletes the underlying object if it exists. See set.
+     */
+    ~AutoAIBinder() { set(nullptr); }
+
+    /**
+     * This takes ownership of a binder from another AIBinder object but it does not affect the
+     * ownership of that other object.
+     */
+    AutoAIBinder& operator=(const AutoAIBinder& other) {
+        AIBinder_incStrong(other.mBinder);
+        set(other.mBinder);
+        return *this;
+    }
+
+    /**
+     * Takes ownership of one strong refcount of binder
+     */
+    void set(AIBinder* binder) {
+        if (mBinder != nullptr) AIBinder_decStrong(mBinder);
+        mBinder = binder;
+    }
+
+    /**
+     * This returns the underlying binder object for transactions. If it is used to create another
+     * AutoAIBinder object, it should first be incremented.
+     */
+    AIBinder* get() const { return mBinder; }
+
+    /**
+     * This allows the value in this class to be set from beneath it. If you call this method and
+     * then change the value of T*, you must take ownership of the value you are replacing and add
+     * ownership to the object that is put in here.
+     *
+     * Recommended use is like this:
+     *   AutoAIBinder a;  // will be nullptr
+     *   SomeInitFunction(a.getR());  // value is initialized with refcount
+     *
+     * Other usecases are discouraged.
+     *
+     */
+    AIBinder** getR() { return &mBinder; }
+
+private:
+    AIBinder* mBinder = nullptr;
+};
+
+/**
+ * This baseclass owns a single object, used to make various classes RAII.
+ */
+template <typename T, void (*Destroy)(T*)>
+class AutoA {
+public:
+    /**
+     * Takes ownership of t.
+     */
+    explicit AutoA(T* t = nullptr) : mT(t) {}
+
+    /**
+     * This deletes the underlying object if it exists. See set.
+     */
+    ~AutoA() { set(nullptr); }
+
+    /**
+     * Takes ownership of t.
+     */
+    void set(T* t) {
+        Destroy(mT);
+        mT = t;
+    }
+
+    /**
+     * This returns the underlying object to be modified but does not affect ownership.
+     */
+    T* get() { return mT; }
+
+    /**
+     * This returns the const underlying object but does not affect ownership.
+     */
+    const T* get() const { return mT; }
+
+    /**
+     * This allows the value in this class to be set from beneath it. If you call this method and
+     * then change the value of T*, you must take ownership of the value you are replacing and add
+     * ownership to the object that is put in here.
+     *
+     * Recommended use is like this:
+     *   AutoA<T> a; // will be nullptr
+     *   SomeInitFunction(a.getR()); // value is initialized with refcount
+     *
+     * Other usecases are discouraged.
+     *
+     */
+    T** getR() { return &mT; }
+
+    // copy-constructing, or move/copy assignment is disallowed
+    AutoA(const AutoA&) = delete;
+    AutoA& operator=(const AutoA&) = delete;
+    AutoA& operator=(AutoA&&) = delete;
+
+    // move-constructing is okay
+    AutoA(AutoA&&) = default;
+
+private:
+    T* mT;
+};
+
+/**
+ * Convenience wrapper. See AParcel.
+ */
+class AutoAParcel : public AutoA<AParcel, AParcel_delete> {
+public:
+    /**
+     * Takes ownership of a.
+     */
+    explicit AutoAParcel(AParcel* a = nullptr) : AutoA(a) {}
+    ~AutoAParcel() {}
+    AutoAParcel(AutoAParcel&&) = default;
+};
+
+/**
+ * Convenience wrapper. See AStatus.
+ */
+class AutoAStatus : public AutoA<AStatus, AStatus_delete> {
+public:
+    /**
+     * Takes ownership of a.
+     */
+    explicit AutoAStatus(AStatus* a = nullptr) : AutoA(a) {}
+    ~AutoAStatus() {}
+    AutoAStatus(AutoAStatus&&) = default;
+
+    /**
+     * See AStatus_isOk.
+     */
+    bool isOk() { return get() != nullptr && AStatus_isOk(get()); }
+};
+
+/**
+ * Convenience wrapper. See AIBinder_DeathRecipient.
+ */
+class AutoAIBinder_DeathRecipient
+      : public AutoA<AIBinder_DeathRecipient, AIBinder_DeathRecipient_delete> {
+public:
+    /**
+     * Takes ownership of a.
+     */
+    explicit AutoAIBinder_DeathRecipient(AIBinder_DeathRecipient* a = nullptr) : AutoA(a) {}
+    ~AutoAIBinder_DeathRecipient() {}
+    AutoAIBinder_DeathRecipient(AutoAIBinder_DeathRecipient&&) = default;
+};
+
+/**
+ * Convenience wrapper. See AIBinder_Weak.
+ */
+class AutoAIBinder_Weak : public AutoA<AIBinder_Weak, AIBinder_Weak_delete> {
+public:
+    /**
+     * Takes ownership of a.
+     */
+    explicit AutoAIBinder_Weak(AIBinder_Weak* a = nullptr) : AutoA(a) {}
+    ~AutoAIBinder_Weak() {}
+    AutoAIBinder_Weak(AutoAIBinder_Weak&&) = default;
+
+    /**
+     * See AIBinder_Weak_promote.
+     */
+    AutoAIBinder promote() { return AutoAIBinder(AIBinder_Weak_promote(get())); }
+};
+
+} // namespace android
+
+#endif // __cplusplus
+
+/** @} */
diff --git a/libs/binder/ndk/include_ndk/android/binder_interface_utils.h b/libs/binder/ndk/include_ndk/android/binder_interface_utils.h
new file mode 100644
index 0000000000..d7e1566010
--- /dev/null
+++ b/libs/binder/ndk/include_ndk/android/binder_interface_utils.h
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2018 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.
+ */
+
+/**
+ * @addtogroup NdkBinder
+ * @{
+ */
+
+/**
+ * @file binder_interface_utils.h
+ * @brief This provides common C++ classes for common operations and as base classes for C++
+ * interfaces.
+ */
+
+#pragma once
+
+#include <android/binder_auto_utils.h>
+#include <android/binder_ibinder.h>
+
+#ifdef __cplusplus
+
+#include <memory>
+#include <mutex>
+
+namespace android {
+
+// analog using std::shared_ptr for RefBase-like semantics
+class SharedRefBase {
+public:
+    SharedRefBase() {}
+    virtual ~SharedRefBase() {}
+
+    std::shared_ptr<SharedRefBase> ref() {
+        std::shared_ptr<SharedRefBase> thiz = mThis.lock();
+
+        std::call_once(mFlagThis, [&]() { mThis = thiz = std::shared_ptr<SharedRefBase>(this); });
+
+        return thiz;
+    }
+
+    template <typename CHILD>
+    std::shared_ptr<CHILD> ref() {
+        return std::static_pointer_cast<CHILD>(ref());
+    }
+
+private:
+    std::once_flag mFlagThis;
+    std::weak_ptr<SharedRefBase> mThis;
+};
+
+// wrapper analog to IInterface
+class ICInterface : public SharedRefBase {
+public:
+    ICInterface() {}
+    virtual ~ICInterface() {}
+
+    // This either returns the single existing implementation or creates a new implementation.
+    virtual AutoAIBinder asBinder() = 0;
+};
+
+// wrapper analog to BnInterface
+template <typename INTERFACE>
+class BnCInterface : public INTERFACE {
+public:
+    BnCInterface() {}
+    virtual ~BnCInterface() {}
+
+    AutoAIBinder asBinder() override;
+
+protected:
+    // This function should only be called by asBinder. Otherwise, there is a possibility of
+    // multiple AIBinder* objects being created for the same instance of an object.
+    virtual AutoAIBinder createBinder() = 0;
+
+private:
+    std::mutex mMutex; // for asBinder
+    AutoAIBinder_Weak mWeakBinder;
+};
+
+// wrapper analog to BpInterfae
+template <typename INTERFACE>
+class BpCInterface : public INTERFACE {
+public:
+    BpCInterface(const AutoAIBinder& binder) : mBinder(binder) {}
+    virtual ~BpCInterface() {}
+
+    AutoAIBinder asBinder() override;
+
+private:
+    AutoAIBinder mBinder;
+};
+
+template <typename INTERFACE>
+AutoAIBinder BnCInterface<INTERFACE>::asBinder() {
+    std::lock_guard<std::mutex> l(mMutex);
+
+    AutoAIBinder binder;
+    if (mWeakBinder.get() != nullptr) {
+        binder.set(AIBinder_Weak_promote(mWeakBinder.get()));
+    }
+    if (binder.get() == nullptr) {
+        binder = createBinder();
+        mWeakBinder.set(AIBinder_Weak_new(binder.get()));
+    }
+
+    return binder;
+}
+
+template <typename INTERFACE>
+AutoAIBinder BpCInterface<INTERFACE>::asBinder() {
+    return mBinder;
+}
+
+#endif // __cplusplus
+
+} // namespace android
+
+/** @} */
diff --git a/libs/binder/ndk/include_ndk/android/binder_parcel.h b/libs/binder/ndk/include_ndk/android/binder_parcel.h
index a3800da160..0e97b507c5 100644
--- a/libs/binder/ndk/include_ndk/android/binder_parcel.h
+++ b/libs/binder/ndk/include_ndk/android/binder_parcel.h
@@ -88,6 +88,43 @@ binder_status_t AParcel_writeStatusHeader(AParcel* parcel, const AStatus* status
 binder_status_t AParcel_readStatusHeader(const AParcel* parcel, AStatus** status)
         __INTRODUCED_IN(29);
 
+/**
+ * Writes string value to the next location in a non-null parcel.
+ */
+binder_status_t AParcel_writeString(AParcel* parcel, const char* string, size_t length)
+        __INTRODUCED_IN(29);
+
+/**
+ * This is called to allocate a buffer
+ *
+ * The length here includes the space required to insert a '\0' for a properly formed c-str. If the
+ * buffer returned from this function is retStr, it will be filled by AParcel_readString with the
+ * data from the remote process, and it will be filled such that retStr[length] == '\0'.
+ *
+ * If allocation fails, null should be returned.
+ */
+typedef void* (*AParcel_string_reallocator)(void* stringData, size_t length);
+
+/**
+ * This is called to get the buffer from a stringData object.
+ */
+typedef char* (*AParcel_string_getter)(void* stringData);
+
+/**
+ * Reads and allocates string value from the next location in a non-null parcel.
+ *
+ * Data is passed to the string allocator once the string size is known. This data should be used to
+ * point to some kind of string data. For instance, it could be a char*, and the string allocator
+ * could be realloc. Then the getter would simply be a cast to char*. In more complicated cases,
+ * stringData could be a structure containing additional string data.
+ *
+ * If this function returns a success, the buffer returned by allocator when passed stringData will
+ * contain a null-terminated c-str read from the binder.
+ */
+binder_status_t AParcel_readString(const AParcel* parcel, AParcel_string_reallocator reallocator,
+                                   AParcel_string_getter getter, void** stringData)
+        __INTRODUCED_IN(29);
+
 // @START
 /**
  * Writes int32_t value to the next location in a non-null parcel.
diff --git a/libs/binder/ndk/include_ndk/android/binder_parcel_utils.h b/libs/binder/ndk/include_ndk/android/binder_parcel_utils.h
new file mode 100644
index 0000000000..7b261d6f98
--- /dev/null
+++ b/libs/binder/ndk/include_ndk/android/binder_parcel_utils.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2018 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.
+ */
+
+/**
+ * @addtogroup NdkBinder
+ * @{
+ */
+
+/**
+ * @file binder_parcel_utils.h
+ * @brief A collection of helper wrappers for AParcel.
+ */
+
+#pragma once
+
+#include <android/binder_parcel.h>
+
+#ifdef __cplusplus
+
+#include <string>
+
+/**
+ * Takes a std::string and reallocates it to the specified length. For use with AParcel_readString.
+ * See use below in AParcel_readString.
+ */
+static inline void* AParcel_std_string_reallocator(void* stringData, size_t length) {
+    std::string* str = static_cast<std::string*>(stringData);
+    str->resize(length - 1);
+    return stringData;
+}
+
+/**
+ * Takes a std::string and returns the inner char*.
+ */
+static inline char* AParcel_std_string_getter(void* stringData) {
+    std::string* str = static_cast<std::string*>(stringData);
+    return &(*str)[0];
+}
+
+/**
+ * Convenience API for writing a std::string.
+ */
+static inline binder_status_t AParcel_writeString(AParcel* parcel, const std::string& str) {
+    return AParcel_writeString(parcel, str.c_str(), str.size());
+}
+
+/**
+ * Convenience API for reading a std::string.
+ */
+static inline binder_status_t AParcel_readString(const AParcel* parcel, std::string* str) {
+    void* stringData = static_cast<void*>(str);
+    return AParcel_readString(parcel, AParcel_std_string_reallocator, AParcel_std_string_getter,
+                              &stringData);
+}
+
+#endif // __cplusplus
+
+/** @} */
diff --git a/libs/binder/ndk/libbinder_ndk.map.txt b/libs/binder/ndk/libbinder_ndk.map.txt
index 4f486c99ba..2a1bff131c 100644
--- a/libs/binder/ndk/libbinder_ndk.map.txt
+++ b/libs/binder/ndk/libbinder_ndk.map.txt
@@ -32,6 +32,7 @@ LIBBINDER_NDK { # introduced=29
     AParcel_readInt64;
     AParcel_readNullableStrongBinder;
     AParcel_readStatusHeader;
+    AParcel_readString;
     AParcel_readStrongBinder;
     AParcel_readUint32;
     AParcel_readUint64;
@@ -43,6 +44,7 @@ LIBBINDER_NDK { # introduced=29
     AParcel_writeInt32;
     AParcel_writeInt64;
     AParcel_writeStatusHeader;
+    AParcel_writeString;
     AParcel_writeStrongBinder;
     AParcel_writeUint32;
     AParcel_writeUint64;
diff --git a/libs/binder/ndk/parcel.cpp b/libs/binder/ndk/parcel.cpp
index 385e898aeb..3e03e907bb 100644
--- a/libs/binder/ndk/parcel.cpp
+++ b/libs/binder/ndk/parcel.cpp
@@ -20,7 +20,11 @@
 #include "ibinder_internal.h"
 #include "status_internal.h"
 
+#include <limits>
+
+#include <android-base/logging.h>
 #include <binder/Parcel.h>
+#include <utils/Unicode.h>
 
 using ::android::IBinder;
 using ::android::Parcel;
@@ -69,6 +73,67 @@ binder_status_t AParcel_readStatusHeader(const AParcel* parcel, AStatus** status
     return ret;
 }
 
+binder_status_t AParcel_writeString(AParcel* parcel, const char* string, size_t length) {
+    const uint8_t* str8 = (uint8_t*)string;
+
+    const ssize_t len16 = utf8_to_utf16_length(str8, length);
+
+    if (len16 < 0 || len16 >= std::numeric_limits<int32_t>::max()) {
+        LOG(WARNING) << __func__ << ": Invalid string length: " << len16;
+        return STATUS_BAD_VALUE;
+    }
+
+    status_t err = parcel->get()->writeInt32(len16);
+    if (err) {
+        return PruneStatusT(err);
+    }
+
+    void* str16 = parcel->get()->writeInplace((len16 + 1) * sizeof(char16_t));
+    if (str16 == nullptr) {
+        return STATUS_NO_MEMORY;
+    }
+
+    utf8_to_utf16(str8, length, (char16_t*)str16, (size_t)len16 + 1);
+
+    return STATUS_OK;
+}
+
+binder_status_t AParcel_readString(const AParcel* parcel, AParcel_string_reallocator reallocator,
+                                   AParcel_string_getter getter, void** stringData) {
+    size_t len16;
+    const char16_t* str16 = parcel->get()->readString16Inplace(&len16);
+
+    if (str16 == nullptr) {
+        LOG(WARNING) << __func__ << ": Failed to read string in place.";
+        return STATUS_UNEXPECTED_NULL;
+    }
+
+    ssize_t len8;
+
+    if (len16 == 0) {
+        len8 = 1;
+    } else {
+        len8 = utf16_to_utf8_length(str16, len16) + 1;
+    }
+
+    if (len8 <= 0 || len8 >= std::numeric_limits<int32_t>::max()) {
+        LOG(WARNING) << __func__ << ": Invalid string length: " << len8;
+        return STATUS_BAD_VALUE;
+    }
+
+    *stringData = reallocator(*stringData, len8);
+    char* str8 = getter(*stringData);
+
+    if (str8 == nullptr) {
+        LOG(WARNING) << __func__ << ": AParcel_string_allocator failed to allocate.";
+        return STATUS_NO_MEMORY;
+    }
+
+    utf16_to_utf8(str16, len16, str8, len8);
+
+    return STATUS_OK;
+}
+
 // See gen_parcel_helper.py. These auto-generated read/write methods use the same types for
 // libbinder and this library.
 // @START
diff --git a/libs/binder/ndk/test/main_client.cpp b/libs/binder/ndk/test/main_client.cpp
index 3fc096a9ed..22bf1e5be5 100644
--- a/libs/binder/ndk/test/main_client.cpp
+++ b/libs/binder/ndk/test/main_client.cpp
@@ -131,3 +131,6 @@ TEST(NdkBinder, AddServiceMultipleTimes) {
     EXPECT_EQ(STATUS_OK, foo->addService(kInstanceName2));
     EXPECT_EQ(IFoo::getService(kInstanceName1), IFoo::getService(kInstanceName2));
 }
+
+#include <android/binder_auto_utils.h>
+#include <android/binder_interface_utils.h>