commit 27fb5200aad12c597d74af696a6e94cf187b3876
author David Anderson <dvander@google.com> Thu Jun 15 12:13:29 2023 -0700
committer David Anderson <dvander@google.com> Thu Jun 22 20:52:10 2023 -0700
tree 5faaec1e9f9ae4ae991e66bad344ef58ad13bc90
parent c7465ab5d2c48eac57d76bd8091cbba3a4b06fe4

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

fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h

diff --git a/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h b/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h
index 3890b17..f599501 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h
@@ -133,6 +133,7 @@
 
     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

diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/cow_reader.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/cow_reader.cpp
index c2a7fdb..4ac89ae 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/cow_reader.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/cow_reader.cpp
@@ -230,7 +230,7 @@
             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 @@
                                             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

diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/inspect_cow.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/inspect_cow.cpp
index 148ecb0..a6dee4f 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/inspect_cow.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/inspect_cow.cpp
@@ -57,7 +57,7 @@
     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 @@
             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;
             }