libbinder: Add binder::Status type

This object implements equivalent functionality to the Java logic which
serializes and re-throws exceptions from services.

Bug: 25615695
Test: Integration test for generated AIDL code reveals this to work
      correctly.

Change-Id: Ic80c9def0dd232582ea9c49717ec50894af6bfc2

1 files changed, 133 insertions, 0 deletions

diff --git a/libs/binder/Status.cpp b/libs/binder/Status.cpp
new file mode 100644
index 0000000000..41fff3d4cd
--- /dev/null
+++ b/libs/binder/Status.cpp
@@ -0,0 +1,133 @@
+/*
+ * 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.
+ */
+
+#include <binder/Status.h>
+
+namespace android {
+namespace binder {
+
+Status Status::fromExceptionCode(int32_t exception_code) {
+    return Status(exception_code, "");
+}
+
+Status Status::fromStatusT(status_t status) {
+    Status ret;
+    ret.setFromStatusT(status);
+    return ret;
+}
+
+Status Status::ok() {
+    return Status();
+}
+
+Status::Status(int32_t exception_code, const String8& message)
+    : mException(exception_code),
+      mMessage(message) {}
+
+Status::Status(int32_t exception_code, const char* message)
+    : mException(exception_code),
+      mMessage(message) {}
+
+status_t Status::readFromParcel(const Parcel& parcel) {
+    status_t status = parcel.readInt32(&mException);
+    if (status != OK) {
+        setFromStatusT(status);
+        return status;
+    }
+
+    // Skip over fat response headers.  Not used (or propagated) in native code.
+    if (mException == EX_HAS_REPLY_HEADER) {
+        // Note that the header size includes the 4 byte size field.
+        const int32_t header_start = parcel.dataPosition();
+        int32_t header_size;
+        status = parcel.readInt32(&header_size);
+        if (status != OK) {
+            setFromStatusT(status);
+            return status;
+        }
+        parcel.setDataPosition(header_start + header_size);
+        // And fat response headers are currently only used when there are no
+        // exceptions, so act like there was no error.
+        mException = EX_NONE;
+    }
+
+    if (mException == EX_NONE) {
+        return status;
+    }
+
+    // The remote threw an exception.  Get the message back.
+    mMessage = String8(parcel.readString16());
+
+    return status;
+}
+
+status_t Status::writeToParcel(Parcel* parcel) const {
+    status_t status = parcel->writeInt32(mException);
+    if (status != OK) { return status; }
+    if (mException == EX_NONE) {
+        // We have no more information to write.
+        return status;
+    }
+    status = parcel->writeString16(String16(mMessage));
+    return status;
+}
+
+void Status::setFromStatusT(status_t status) {
+    switch (status) {
+        case NO_ERROR:
+            mException = EX_NONE;
+            mMessage.clear();
+            break;
+        case UNEXPECTED_NULL:
+            mException = EX_NULL_POINTER;
+            mMessage.setTo("Unexpected null reference in Parcel");
+            break;
+        default:
+            mException = EX_TRANSACTION_FAILED;
+            mMessage.setTo("Transaction failed");
+            break;
+    }
+}
+
+void Status::setException(int32_t ex, const String8& message) {
+    mException = ex;
+    mMessage.setTo(message);
+}
+
+void Status::getException(int32_t* returned_exception,
+                          String8* returned_message) const {
+    if (returned_exception) {
+        *returned_exception = mException;
+    }
+    if (returned_message) {
+        returned_message->setTo(mMessage);
+    }
+}
+
+String8 Status::toString8() const {
+    String8 ret;
+    if (mException == EX_NONE) {
+        ret.append("No error");
+    } else {
+        ret.appendFormat("Status(%d): '", mException);
+        ret.append(String8(mMessage));
+        ret.append("'");
+    }
+    return ret;
+}
+
+}  // namespace binder
+}  // namespace android