From b6134a6d4e6196d2c3bb3094db55373fc068ab9f Mon Sep 17 00:00:00 2001
From: David Anderson <dvander@google.com>
Date: Fri, 26 Oct 2018 13:08:44 -0700
Subject: [PATCH] fastbootd: Remove metadata merging code.

The purpose of this code was to support preserving partitions across a
flashall operation. Since we are not supporting persistent read-write
partitions, this merging code is effectively useless - it is preserving
only partitions that will be deleted.

Additionally, this code does not merge partition group changes, since
doing so accurately is difficult. Partition size changes aren't sent
until after update-super resolves, so a valid re-grouping could be
rejected during update-super if the existing partitions are too big.

This patch removes the update-super merging code until a use case comes
along and we can properly evaluate how it should work.

Bug: N/A
Test: fastboot flashall
Change-Id: I1d622b23dabdf031897be9de49f59fc8cf3caf3b
---
 fastboot/device/flashing.cpp | 43 ++++--------------------------------
 fastboot/device/flashing.h   |  2 +-
 2 files changed, 5 insertions(+), 40 deletions(-)

diff --git a/fastboot/device/flashing.cpp b/fastboot/device/flashing.cpp
index 2347496b9..e3d84e098 100644
--- a/fastboot/device/flashing.cpp
+++ b/fastboot/device/flashing.cpp
@@ -104,12 +104,7 @@ int Flash(FastbootDevice* device, const std::string& partition_name) {
     return FlashBlockDevice(handle.fd(), data);
 }
 
-bool UpdateSuper(FastbootDevice* device, const std::string& partition_name, bool wipe) {
-    std::optional<std::string> super = FindPhysicalPartition(partition_name);
-    if (!super) {
-        return device->WriteFail("Could not find partition: " + partition_name);
-    }
-
+bool UpdateSuper(FastbootDevice* device, const std::string& super_name, bool wipe) {
     std::vector<char> data = std::move(device->download_data());
     if (data.empty()) {
         return device->WriteFail("No data available");
@@ -125,47 +120,17 @@ bool UpdateSuper(FastbootDevice* device, const std::string& partition_name, bool
     // image.
     std::string slot_suffix = device->GetCurrentSlot();
     uint32_t slot_number = SlotNumberForSlotSuffix(slot_suffix);
-    std::unique_ptr<LpMetadata> metadata = ReadMetadata(super->c_str(), slot_number);
-    if (!metadata || wipe) {
-        if (!FlashPartitionTable(super.value(), *new_metadata.get())) {
+    if (wipe || !ReadMetadata(super_name, slot_number)) {
+        if (!FlashPartitionTable(super_name, *new_metadata.get())) {
             return device->WriteFail("Unable to flash new partition table");
         }
         return device->WriteOkay("Successfully flashed partition table");
     }
 
-    // There's a working super partition, and we don't want to wipe it - it may
-    // may contain partitions created for the user. Instead, we create a zero-
-    // sized partition for each entry in the new partition table. It is then
-    // the host's responsibility to size it correctly via resize-logical-partition.
-    std::unique_ptr<MetadataBuilder> builder = MetadataBuilder::New(*metadata.get());
-    if (!builder) {
-        return device->WriteFail("Unable to create a metadata builder");
-    }
-    for (const auto& partition : new_metadata->partitions) {
-        std::string name = GetPartitionName(partition);
-        if (builder->FindPartition(name)) {
-            continue;
-        }
-        if (!builder->AddPartition(name, partition.attributes)) {
-            return device->WriteFail("Unable to add partition: " + name);
-        }
-    }
-
-    // The scratch partition may exist as temporary storage, created for
-    // use by adb remount for overlayfs. If we're performing a flashall
-    // operation then we want to start over with a clean slate, so we
-    // remove the scratch partition until it is requested again.
-    builder->RemovePartition("scratch");
-
-    new_metadata = builder->Export();
-    if (!new_metadata) {
-        return device->WriteFail("Unable to export new partition table");
-    }
-
     // Write the new table to every metadata slot.
     bool ok = true;
     for (size_t i = 0; i < new_metadata->geometry.metadata_slot_count; i++) {
-        ok &= UpdatePartitionTable(super.value(), *new_metadata.get(), i);
+        ok &= UpdatePartitionTable(super_name, *new_metadata.get(), i);
     }
 
     if (!ok) {
diff --git a/fastboot/device/flashing.h b/fastboot/device/flashing.h
index 89e20fce2..b15f28b96 100644
--- a/fastboot/device/flashing.h
+++ b/fastboot/device/flashing.h
@@ -22,4 +22,4 @@
 class FastbootDevice;
 
 int Flash(FastbootDevice* device, const std::string& partition_name);
-bool UpdateSuper(FastbootDevice* device, const std::string& partition_name, bool wipe);
+bool UpdateSuper(FastbootDevice* device, const std::string& super_name, bool wipe);