[arrow] branch master updated: ARROW-16002: [Go] fileBlock.NewMessage should use memory.Allocator (#13554)

[zeroshade]

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The following commit(s) were added to refs/heads/master by this push:
     new e766828c69 ARROW-16002: [Go] fileBlock.NewMessage should use 
memory.Allocator (#13554)
e766828c69 is described below

commit e766828c699c6c74eba3b8c5de99e541017b8b9e
Author: Matt Topol <zotthewiz...@gmail.com>
AuthorDate: Wed Jul 13 16:47:31 2022 -0400

    ARROW-16002: [Go] fileBlock.NewMessage should use memory.Allocator (#13554)
    
    Share the `FileReader`'s allocator with the `fileBlock` objects so that the 
`NewMessage` can be allocated using the memory allocator. Allowing for re-use 
if the Allocator allows it
    
    Lead-authored-by: Matt Topol <zotthewiz...@gmail.com>
    Co-authored-by: Matthew Topol <mto...@factset.com>
    Signed-off-by: Matthew Topol <mto...@factset.com>
---
 go/arrow/ipc/file_reader.go |  2 ++
 go/arrow/ipc/metadata.go    | 27 +++++++++++++++++++--------
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/go/arrow/ipc/file_reader.go b/go/arrow/ipc/file_reader.go
index 068d5ebbc9..ab6e7bf108 100644
--- a/go/arrow/ipc/file_reader.go
+++ b/go/arrow/ipc/file_reader.go
@@ -188,6 +188,7 @@ func (f *FileReader) block(i int) (fileBlock, error) {
                Meta:   blk.MetaDataLength(),
                Body:   blk.BodyLength(),
                r:      f.r,
+               mem:    f.mem,
        }, nil
 }
 
@@ -202,6 +203,7 @@ func (f *FileReader) dict(i int) (fileBlock, error) {
                Meta:   blk.MetaDataLength(),
                Body:   blk.BodyLength(),
                r:      f.r,
+               mem:    f.mem,
        }, nil
 }
 
diff --git a/go/arrow/ipc/metadata.go b/go/arrow/ipc/metadata.go
index 132dfb6976..eaf2228f37 100644
--- a/go/arrow/ipc/metadata.go
+++ b/go/arrow/ipc/metadata.go
@@ -65,7 +65,8 @@ type fileBlock struct {
        Meta   int32
        Body   int64
 
-       r io.ReaderAt
+       r   io.ReaderAt
+       mem memory.Allocator
 }
 
 func fileBlocksToFB(b *flatbuffers.Builder, blocks []fileBlock, start 
startVecFunc) flatbuffers.UOffsetT {
@@ -80,12 +81,18 @@ func fileBlocksToFB(b *flatbuffers.Builder, blocks 
[]fileBlock, start startVecFu
 
 func (blk fileBlock) NewMessage() (*Message, error) {
        var (
-               err error
-               buf []byte
-               r   = blk.section()
+               err  error
+               buf  []byte
+               body *memory.Buffer
+               meta *memory.Buffer
+               r    = blk.section()
        )
 
-       buf = make([]byte, blk.Meta)
+       meta = memory.NewResizableBuffer(blk.mem)
+       meta.Resize(int(blk.Meta))
+       defer meta.Release()
+
+       buf = meta.Bytes()
        _, err = io.ReadFull(r, buf)
        if err != nil {
                return nil, fmt.Errorf("arrow/ipc: could not read message 
metadata: %w", err)
@@ -102,14 +109,18 @@ func (blk fileBlock) NewMessage() (*Message, error) {
                prefix = 4
        }
 
-       meta := memory.NewBufferBytes(buf[prefix:]) // drop buf-size already 
known from blk.Meta
+       // drop buf-size already known from blk.Meta
+       meta = memory.SliceBuffer(meta, prefix, int(blk.Meta)-prefix)
+       defer meta.Release()
 
-       buf = make([]byte, blk.Body)
+       body = memory.NewResizableBuffer(blk.mem)
+       defer body.Release()
+       body.Resize(int(blk.Body))
+       buf = body.Bytes()
        _, err = io.ReadFull(r, buf)
        if err != nil {
                return nil, fmt.Errorf("arrow/ipc: could not read message body: 
%w", err)
        }
-       body := memory.NewBufferBytes(buf)
 
        return NewMessage(meta, body), nil
 }