From 6bac4935eaec2a54aa76c115387d93816793255a Mon Sep 17 00:00:00 2001
From: Chris Hogan <c096h800@gmail.com>
Date: Tue, 6 Apr 2021 15:09:21 -0500
Subject: [PATCH] Add size and pointer version of Bucket::Get

---
 src/api/bucket.cc   | 20 +++++++++++++++-----
 src/api/bucket.h    |  2 +-
 src/buffer_pool.cc  | 17 ++++++++++++-----
 src/buffer_pool.h   |  3 +++
 test/bucket_test.cc | 10 ++++++++++
 5 files changed, 41 insertions(+), 11 deletions(-)

diff --git a/src/api/bucket.cc b/src/api/bucket.cc
index 27cc78be4..03addea3f 100644
--- a/src/api/bucket.cc
+++ b/src/api/bucket.cc
@@ -95,6 +95,13 @@ size_t Bucket::GetBlobSize(Arena *arena, const std::string &name,
 }
 
 size_t Bucket::Get(const std::string &name, Blob &user_blob, Context &ctx) {
+  size_t ret = Get(name, user_blob.data(), user_blob.size(), ctx);
+
+  return ret;
+}
+
+size_t Bucket::Get(const std::string &name, void *user_blob, size_t blob_size,
+                   Context &ctx) {
   (void)ctx;
 
   size_t ret = 0;
@@ -103,14 +110,17 @@ size_t Bucket::Get(const std::string &name, Blob &user_blob, Context &ctx) {
     // TODO(chogan): Assumes scratch is big enough to hold buffer_ids
     ScopedTemporaryMemory scratch(&hermes_->trans_arena_);
 
-    if (user_blob.size() == 0) {
-      ret = GetBlobSize(scratch, name, ctx);
-    } else {
+    if (user_blob && blob_size != 0) {
+      hermes::Blob blob = {};
+      blob.data = (u8 *)user_blob;
+      blob.size = blob_size;
       LOG(INFO) << "Getting Blob " << name << " from bucket " << name_ << '\n';
       BlobID blob_id = GetBlobId(&hermes_->context_, &hermes_->rpc_,
-                                       name, id_);
+                                 name, id_);
       ret = ReadBlobById(&hermes_->context_, &hermes_->rpc_,
-                         &hermes_->trans_arena_, user_blob, blob_id);
+                         &hermes_->trans_arena_, blob, blob_id);
+    } else {
+      ret = GetBlobSize(scratch, name, ctx);
     }
   }
 
diff --git a/src/api/bucket.h b/src/api/bucket.h
index e8155be8e..37f16f179 100644
--- a/src/api/bucket.h
+++ b/src/api/bucket.h
@@ -144,7 +144,7 @@ class Bucket {
   /**
    * \brief Retrieve a Blob into a user buffer.
    */
-  size_t Get(const std::string &name, void *user_blob, size_t buffer_size,
+  size_t Get(const std::string &name, void *user_blob, size_t blob_size,
              Context &ctx);
 
   /** get blob(s) on this bucket according to predicate */
diff --git a/src/buffer_pool.cc b/src/buffer_pool.cc
index 52ce933bd..3e3f4b1f6 100644
--- a/src/buffer_pool.cc
+++ b/src/buffer_pool.cc
@@ -1529,11 +1529,8 @@ size_t ReadBlobFromBuffers(SharedMemoryContext *context, RpcContext *rpc,
 }
 
 size_t ReadBlobById(SharedMemoryContext *context, RpcContext *rpc, Arena *arena,
-                    api::Blob &dest, BlobID blob_id) {
+                    Blob blob, BlobID blob_id) {
   size_t result = 0;
-  hermes::Blob blob = {};
-  blob.data = dest.data();
-  blob.size = dest.size();
 
   BufferIdArray buffer_ids = {};
   if (hermes::BlobIsInSwap(blob_id)) {
@@ -1543,7 +1540,7 @@ size_t ReadBlobById(SharedMemoryContext *context, RpcContext *rpc, Arena *arena,
   } else {
     u32 *buffer_sizes = 0;
     buffer_ids = GetBufferIdsFromBlobId(arena, context, rpc, blob_id,
-                                          &buffer_sizes);
+                                        &buffer_sizes);
     result = ReadBlobFromBuffers(context, rpc, &blob, &buffer_ids,
                                  buffer_sizes);
   }
@@ -1551,6 +1548,16 @@ size_t ReadBlobById(SharedMemoryContext *context, RpcContext *rpc, Arena *arena,
   return result;
 }
 
+size_t ReadBlobById(SharedMemoryContext *context, RpcContext *rpc, Arena *arena,
+                    api::Blob &dest, BlobID blob_id) {
+  hermes::Blob blob = {};
+  blob.data = dest.data();
+  blob.size = dest.size();
+  size_t result = ReadBlobById(context, rpc, arena, blob, blob_id);
+
+  return result;
+}
+
 int OpenSwapFile(SharedMemoryContext *context, u32 node_id) {
   int result = 0;
 
diff --git a/src/buffer_pool.h b/src/buffer_pool.h
index b7aefba25..ed9dd30d9 100644
--- a/src/buffer_pool.h
+++ b/src/buffer_pool.h
@@ -435,6 +435,9 @@ size_t ReadBlobFromBuffers(SharedMemoryContext *context, RpcContext *rpc,
                            Blob *blob, BufferIdArray *buffer_ids,
                            u32 *buffer_sizes);
 
+size_t ReadBlobById(SharedMemoryContext *context, RpcContext *rpc, Arena *arena,
+                    Blob blob, BlobID blob_id);
+
 size_t ReadBlobById(SharedMemoryContext *context, RpcContext *rpc, Arena *arena,
                     api::Blob &dest, BlobID blob_id);
 
diff --git a/test/bucket_test.cc b/test/bucket_test.cc
index 32d505c28..e7fe5d224 100644
--- a/test/bucket_test.cc
+++ b/test/bucket_test.cc
@@ -232,6 +232,16 @@ void TestMultiGet(std::shared_ptr<hapi::Hermes> hermes) {
     Assert(blobs[i] == retrieved_blobs[i]);
   }
 
+  // Test Get into user buffer
+  hermes::u8 user_buffer[blob_size] = {};
+  size_t b1_size = bucket.Get(blob_names[0], nullptr, 0, ctx);
+  Assert(b1_size == blob_size);
+  b1_size = bucket.Get(blob_names[0], user_buffer, b1_size, ctx);
+
+  for (size_t i = 0; i < b1_size; ++i) {
+    Assert(user_buffer[i] == blobs[0][i]);
+  }
+
   bucket.Destroy(ctx);
 }