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Commit 27fb5200 authored by David Anderson's avatar David Anderson
Browse files

libsnapshot: Add a helper around CowReader::GetRawBytes. 

This avoids having to use op->source which will require more work after
the new format lands.

Bug: 280529365
Test: inspect_cow
Change-Id: Iffa18974bb0152dad73d69bb03c683f1aa549031
parent c7465ab5

fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h

+1 −0
Original line number Diff line number Diff line
@@ -133,6 +133,7 @@ class CowReader final : public ICowReader { 


    CowHeader& GetHeader() override { return header_; }



    bool GetRawBytes(const CowOperation* op, void* buffer, size_t len, size_t* read);

    bool GetRawBytes(uint64_t offset, void* buffer, size_t len, size_t* read);



    // Returns the total number of data ops that should be merged. This is the

fs_mgr/libsnapshot/libsnapshot_cow/cow_reader.cpp

+13 −1
Original line number Diff line number Diff line
@@ -230,7 +230,7 @@ bool CowReader::PrepMergeOps() { 
            size_t seq_len = current_op.data_length / sizeof(uint32_t);



            merge_op_blocks->resize(merge_op_blocks->size() + seq_len);

            if (!GetRawBytes(current_op.source, &merge_op_blocks->data()[num_seqs],

            if (!GetRawBytes(&current_op, &merge_op_blocks->data()[num_seqs],

                             current_op.data_length, &read)) {

                PLOG(ERROR) << "Failed to read sequence op!";

                return false;
@@ -516,6 +516,18 @@ std::unique_ptr<ICowOpIter> CowReader::GetMergeOpIter(bool ignore_progress) { 
                                            ignore_progress ? 0 : merge_op_start_);

}



bool CowReader::GetRawBytes(const CowOperation* op, void* buffer, size_t len, size_t* read) {

    switch (op->type) {

        case kCowSequenceOp:

        case kCowReplaceOp:

        case kCowXorOp:

            return GetRawBytes(op->source, buffer, len, read);

        default:

            LOG(ERROR) << "Cannot get raw bytes of non-data op: " << *op;

            return false;

    }

}



bool CowReader::GetRawBytes(uint64_t offset, void* buffer, size_t len, size_t* read) {

    // Validate the offset, taking care to acknowledge possible overflow of offset+len.

    if (offset < header_.prefix.header_size || offset >= fd_size_ - sizeof(CowFooter) ||

fs_mgr/libsnapshot/libsnapshot_cow/inspect_cow.cpp

+2 −2
Original line number Diff line number Diff line
@@ -57,7 +57,7 @@ static void ShowBad(CowReader& reader, const struct CowOperation* op) { 
    size_t count;

    auto buffer = std::make_unique<uint8_t[]>(op->data_length);



    if (!reader.GetRawBytes(op->source, buffer.get(), op->data_length, &count)) {

    if (!reader.GetRawBytes(op, buffer.get(), op->data_length, &count)) {

        std::cerr << "Failed to read at all!\n";

    } else {

        std::cout << "The Block data is:\n";
@@ -199,7 +199,7 @@ static bool Inspect(const std::string& path) { 
            std::vector<uint32_t> merge_op_blocks;

            size_t seq_len = op->data_length / sizeof(uint32_t);

            merge_op_blocks.resize(seq_len);

            if (!reader.GetRawBytes(op->source, merge_op_blocks.data(), op->data_length, &read)) {

            if (!reader.GetRawBytes(op, merge_op_blocks.data(), op->data_length, &read)) {

                PLOG(ERROR) << "Failed to read sequence op!";

                return false;

            }