liblp: Add a ResizePartition helper to MetadataBuilder.

This change is to assist with implementing the fastbootd "resize-partition"
command. The GrowPartition and ShrinkPartition functions are now
private.

Bug: 78793464
Test: N/A
Change-Id: Ic66a3052359e2558663272ff6e014704206b197e

1 files changed, 18 insertions, 15 deletions

diff --git a/fs_mgr/liblp/builder.cpp b/fs_mgr/liblp/builder.cpp
index 9d710f90b..d6eee6b32 100644
--- a/fs_mgr/liblp/builder.cpp
+++ b/fs_mgr/liblp/builder.cpp
@@ -82,11 +82,7 @@ void Partition::RemoveExtents() {
     extents_.clear();
 }
 
-void Partition::ShrinkTo(uint64_t requested_size) {
-    uint64_t aligned_size = AlignTo(requested_size, LP_SECTOR_SIZE);
-    if (size_ <= aligned_size) {
-        return;
-    }
+void Partition::ShrinkTo(uint64_t aligned_size) {
     if (aligned_size == 0) {
         RemoveExtents();
         return;
@@ -106,7 +102,7 @@ void Partition::ShrinkTo(uint64_t requested_size) {
         sectors_to_remove -= extent->num_sectors();
         extents_.pop_back();
     }
-    DCHECK(size_ == requested_size);
+    DCHECK(size_ == aligned_size);
 }
 
 std::unique_ptr<MetadataBuilder> MetadataBuilder::New(const std::string& block_device,
@@ -290,13 +286,7 @@ void MetadataBuilder::RemovePartition(const std::string& name) {
     }
 }
 
-bool MetadataBuilder::GrowPartition(Partition* partition, uint64_t requested_size) {
-    // Align the space needed up to the nearest sector.
-    uint64_t aligned_size = AlignTo(requested_size, LP_SECTOR_SIZE);
-    if (partition->size() >= aligned_size) {
-        return true;
-    }
-
+bool MetadataBuilder::GrowPartition(Partition* partition, uint64_t aligned_size) {
     // Figure out how much we need to allocate.
     uint64_t space_needed = aligned_size - partition->size();
     uint64_t sectors_needed = space_needed / LP_SECTOR_SIZE;
@@ -394,8 +384,8 @@ bool MetadataBuilder::GrowPartition(Partition* partition, uint64_t requested_siz
     return true;
 }
 
-void MetadataBuilder::ShrinkPartition(Partition* partition, uint64_t requested_size) {
-    partition->ShrinkTo(requested_size);
+void MetadataBuilder::ShrinkPartition(Partition* partition, uint64_t aligned_size) {
+    partition->ShrinkTo(aligned_size);
 }
 
 std::unique_ptr<LpMetadata> MetadataBuilder::Export() {
@@ -465,5 +455,18 @@ void MetadataBuilder::set_block_device_info(const BlockDeviceInfo& device_info)
     }
 }
 
+bool MetadataBuilder::ResizePartition(Partition* partition, uint64_t requested_size) {
+    // Align the space needed up to the nearest sector.
+    uint64_t aligned_size = AlignTo(requested_size, LP_SECTOR_SIZE);
+
+    if (aligned_size > partition->size()) {
+        return GrowPartition(partition, aligned_size);
+    }
+    if (aligned_size < partition->size()) {
+        ShrinkPartition(partition, aligned_size);
+    }
+    return true;
+}
+
 }  // namespace fs_mgr
 }  // namespace android