Remove BlockCache::writeToBuffer

Summary:
- Fix lint in RegionManager
- Remove Region::writeToBuffer().  Previous diffs removed the intermediate copy, this was only used in tests.

Reviewed By: AlnisM

Differential Revision: D108615063

fbshipit-source-id: 11ee8570c25b4a8a88f9e2680a6ec2b4e5e74a89

Author: rlyerly

cachelib/navy/block_cache/Region.cpp

@@ -182,14 +182,6 @@ RelAddress Region::allocateLocked(uint32_t size) {
   return RelAddress{regionId_, offset};
 }
 
-void Region::writeToBuffer(uint32_t offset, BufferView buf) {
-  std::lock_guard l{lock_};
-  XDCHECK_NE(buffer_, nullptr);
-  auto size = buf.size();
-  XDCHECK_LE(offset + size, buffer_->size());
-  memcpy(buffer_->data() + offset, buf.data(), size);
-}
-
 void Region::readFromBuffer(uint32_t fromOffset,
                             MutableBufferView outBuf) const {
   std::lock_guard l{lock_};

cachelib/navy/block_cache/Region.h

@@ -142,9 +142,6 @@ class Region {
     return 0;
   }
 
-  // Writes buf to attached buffer at offset 'offset'.
-  void writeToBuffer(uint32_t offset, BufferView buf);
-
   // Reads from attached buffer from 'fromOffset' into 'outBuf'.
   void readFromBuffer(uint32_t fromOffset, MutableBufferView outBuf) const;
 

cachelib/navy/block_cache/RegionManager.cpp

@@ -228,7 +228,7 @@ RegionManager::getCleanRegion(RegionId& rid, bool addWaiter) {
     return {OpenStatus::Retry, nullptr};
   }
 
-  auto status = OpenStatus::Retry;
+  OpenStatus status;
   std::unique_ptr<CondWaiter> waiter;
   uint32_t newSched = 0;
   {

cachelib/navy/block_cache/tests/RegionTest.cpp

@@ -73,12 +73,13 @@ TEST(Region, BufferAttachDetach) {
   Region r{RegionId(0), 1024};
   r.attachBuffer(std::move(b));
   EXPECT_TRUE(r.hasBuffer());
-  Buffer writeBuf(1024);
-  memset(writeBuf.data(), 'A', 1024);
+  auto [desc, _, writeView] = r.openAndAllocate(1024);
+  memset(writeView.data(), 'A', 1024);
+  r.close(std::move(desc));
   Buffer readBuf(1024);
-  r.writeToBuffer(0, writeBuf.view());
   r.readFromBuffer(0, readBuf.mutableView());
-  EXPECT_TRUE(writeBuf.view() == readBuf.view());
+  const std::vector<char> expected(1024, 'A');
+  EXPECT_EQ(std::memcmp(expected.data(), readBuf.data(), 1024), 0);
   b = r.detachBuffer();
   EXPECT_FALSE(r.hasBuffer());
 }