From 52f882d27428307d05c0d49972f87b70f01b690a Mon Sep 17 00:00:00 2001
From: Dmitry Vedenko <dmitry@crsib.me>
Date: Fri, 12 Apr 2024 15:26:11 +0300
Subject: [PATCH] Reduces the amount of reallocations needed

This performance problem was observed while fixing 16 bit encoding.

Reading six 500Mb blocks required 32Gb of RAM
---
 .../sync/RemoteProjectSnapshot.cpp            | 23 +++++++++++++++++--
 .../sync/WavPackCompressor.cpp                |  5 ++++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/libraries/lib-cloud-audiocom/sync/RemoteProjectSnapshot.cpp b/libraries/lib-cloud-audiocom/sync/RemoteProjectSnapshot.cpp
index 5014c3095d03..65cdd36a6a0c 100644
--- a/libraries/lib-cloud-audiocom/sync/RemoteProjectSnapshot.cpp
+++ b/libraries/lib-cloud-audiocom/sync/RemoteProjectSnapshot.cpp
@@ -413,10 +413,28 @@ void RemoteProjectSnapshot::DownloadBlob(
       });
 }
 
+namespace
+{
+std::vector<uint8_t>
+ReadResponseData(audacity::network_manager::IResponse& response)
+{
+   const auto size = response.getBytesAvailable();
+
+   if (size == 0)
+      return response.readAll<std::vector<uint8_t>>();
+
+   std::vector<uint8_t> data(size);
+   response.readData(data.data(), size);
+
+   return data;
+}
+} // namespace
+
+
 void RemoteProjectSnapshot::OnProjectBlobDownloaded(
    audacity::network_manager::ResponsePtr response)
 {
-   const std::vector<uint8_t> data = response->readAll();
+   const std::vector<uint8_t> data = ReadResponseData(*response);
    uint64_t dictSize               = 0;
 
    if (data.size() < sizeof(uint64_t))
@@ -511,7 +529,8 @@ void RemoteProjectSnapshot::OnProjectBlobDownloaded(
 void RemoteProjectSnapshot::OnBlockDownloaded(
    std::string blockHash, audacity::network_manager::ResponsePtr response)
 {
-   const auto compressedData = response->readAll<std::vector<uint8_t>>();
+   const auto compressedData = ReadResponseData(*response);
+
    const auto blockData =
       DecompressBlock(compressedData.data(), compressedData.size());
 
diff --git a/libraries/lib-cloud-audiocom/sync/WavPackCompressor.cpp b/libraries/lib-cloud-audiocom/sync/WavPackCompressor.cpp
index 671d21e0cb59..288f4d4f53f2 100644
--- a/libraries/lib-cloud-audiocom/sync/WavPackCompressor.cpp
+++ b/libraries/lib-cloud-audiocom/sync/WavPackCompressor.cpp
@@ -80,6 +80,11 @@ struct Exporter final
       const size_t samplesRead = Block.Block->GetSamples(
          sampleData.data(), Block.Format, 0, sampleCount, false);
 
+      // Reserve 1.5 times the size of the original data
+      // The compressed data will be smaller than the original data,
+      // but we overallocate just in case
+      CompressedData.reserve(sampleData.size() * 3 / 2);
+
       if (sampleFormat == int16Sample)
       {
          constexpr size_t conversionSamplesCount = 4096;