Implement c++ native lib for streaming proto, part 1
Extract protobuf class out and creates EncodedBuffer class
which holds protobuf data.
Next step is to create a ProtoOutputStream and let incident helper
adapt the change as well.
please see frameworks/base/core/java/android/util/proto
Bug: 65641021
Test: unit tested
Change-Id: I0dd343b2e62d60f091c8f857fae3452ec8da6b96
diff --git a/cmds/incidentd/src/PrivacyBuffer.cpp b/cmds/incidentd/src/PrivacyBuffer.cpp
new file mode 100644
index 0000000..07a064cf
--- /dev/null
+++ b/cmds/incidentd/src/PrivacyBuffer.cpp
@@ -0,0 +1,168 @@
+/*
+ * Copyright (C) 2017 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 "PrivacyBuffer.h"
+#include "io_util.h"
+
+#include <android/util/protobuf.h>
+#include <deque>
+
+using namespace android::util;
+
+/**
+ * Write the field to buf based on the wire type, iterator will point to next field.
+ * If skip is set to true, no data will be written to buf. Return number of bytes written.
+ */
+static size_t
+write_field_or_skip(EncodedBuffer::iterator* iter, EncodedBuffer* buf, uint8_t wireType, bool skip)
+{
+ EncodedBuffer::Pointer snapshot = iter->rp()->copy();
+ size_t bytesToWrite = 0;
+ uint32_t varint = 0;
+ switch (wireType) {
+ case WIRE_TYPE_VARINT:
+ varint = iter->readRawVarint();
+ if(!skip) return buf->writeRawVarint(varint);
+ break;
+ case WIRE_TYPE_FIXED64:
+ bytesToWrite = 8;
+ break;
+ case WIRE_TYPE_LENGTH_DELIMITED:
+ bytesToWrite = iter->readRawVarint();
+ if(!skip) buf->writeRawVarint(bytesToWrite);
+ break;
+ case WIRE_TYPE_FIXED32:
+ bytesToWrite = 4;
+ break;
+ }
+ if (skip) {
+ iter->rp()->move(bytesToWrite);
+ } else {
+ for (size_t i=0; i<bytesToWrite; i++) {
+ *buf->writeBuffer() = iter->next();
+ buf->wp()->move();
+ }
+ }
+ return skip ? 0 : iter->rp()->pos() - snapshot.pos();
+}
+
+/**
+ * Strip next field based on its private policy and request spec, then stores data in buf.
+ * Return NO_ERROR if succeeds, otherwise BAD_VALUE is returned to indicate bad data in FdBuffer.
+ *
+ * The iterator must point to the head of a protobuf formatted field for successful operation.
+ * After exit with NO_ERROR, iterator points to the next protobuf field's head.
+ */
+static status_t
+stripField(EncodedBuffer::iterator* iter, EncodedBuffer* buf, const Privacy* parentPolicy, const PrivacySpec& spec)
+{
+ if (!iter->hasNext() || parentPolicy == NULL) return BAD_VALUE;
+ uint32_t varint = iter->readRawVarint();
+ uint8_t wireType = read_wire_type(varint);
+ uint32_t fieldId = read_field_id(varint);
+ const Privacy* policy = parentPolicy->lookup(fieldId);
+
+ if (policy == NULL || !policy->IsMessageType() || !policy->HasChildren()) {
+ bool skip = !spec.CheckPremission(policy);
+ size_t amt = buf->size();
+ if (!skip) amt += buf->writeHeader(fieldId, wireType);
+ amt += write_field_or_skip(iter, buf, wireType, skip); // point to head of next field
+ return buf->size() != amt ? BAD_VALUE : NO_ERROR;
+ }
+ // current field is message type and its sub-fields have extra privacy policies
+ deque<EncodedBuffer*> q;
+ uint32_t msgSize = iter->readRawVarint();
+ size_t finalSize = 0;
+ EncodedBuffer::Pointer start = iter->rp()->copy();
+ while (iter->rp()->pos() - start.pos() != msgSize) {
+ EncodedBuffer* v = new EncodedBuffer();
+ status_t err = stripField(iter, v, policy, spec);
+ if (err != NO_ERROR) return err;
+ if (v->size() == 0) continue;
+ q.push_back(v);
+ finalSize += v->size();
+ }
+
+ buf->writeHeader(fieldId, wireType);
+ buf->writeRawVarint(finalSize);
+ while (!q.empty()) {
+ EncodedBuffer* subField = q.front();
+ EncodedBuffer::iterator it = subField->begin();
+ while (it.hasNext()) {
+ *buf->writeBuffer() = it.next();
+ buf->wp()->move();
+ }
+ q.pop_front();
+ delete subField;
+ }
+ return NO_ERROR;
+}
+
+// ================================================================================
+PrivacyBuffer::PrivacyBuffer(const Privacy* policy, EncodedBuffer::iterator& data)
+ :mPolicy(policy),
+ mData(data),
+ mBuffer(0),
+ mSize(0)
+{
+}
+
+PrivacyBuffer::~PrivacyBuffer()
+{
+}
+
+status_t
+PrivacyBuffer::strip(const PrivacySpec& spec)
+{
+ // optimization when no strip happens
+ if (mPolicy == NULL || !mPolicy->HasChildren() || spec.RequireAll()) {
+ if (spec.CheckPremission(mPolicy)) mSize = mData.size();
+ return NO_ERROR;
+ }
+ while (mData.hasNext()) {
+ status_t err = stripField(&mData, &mBuffer, mPolicy, spec);
+ if (err != NO_ERROR) return err;
+ }
+ if (mData.bytesRead() != mData.size()) return BAD_VALUE;
+ mSize = mBuffer.size();
+ mData.rp()->rewind(); // rewind the read pointer back to beginning after the strip.
+ return NO_ERROR;
+}
+
+void
+PrivacyBuffer::clear()
+{
+ mSize = 0;
+ mBuffer.wp()->rewind();
+}
+
+size_t
+PrivacyBuffer::size() const { return mSize; }
+
+status_t
+PrivacyBuffer::flush(int fd)
+{
+ status_t err = NO_ERROR;
+ EncodedBuffer::iterator iter = size() == mData.size() ? mData : mBuffer.begin();
+ while (iter.readBuffer() != NULL) {
+ err = write_all(fd, iter.readBuffer(), iter.currentToRead());
+ iter.rp()->move(iter.currentToRead());
+ if (err != NO_ERROR) return err;
+ }
+ return NO_ERROR;
+}