use multi range requests (#800)

- Improvement: `zen builds download` now uses multi-range requests for blocks to reduce download size
- Improvement: `zen oplog-import` now uses partial block with multi-range requests for blocks to reduce download size
- Improvement: Improved feedback in log/console during `zen oplog-import`
- Improvement: `--allow-partial-block-requests` now defaults to `true` for `zen builds download` and `zen oplog-import` (was `mixed`)
- Improvement: Improved range merging analysis when downloading partial blocks

3 files changed, 22 insertions, 26 deletions

diff --git a/src/zenhttp/clients/httpclientcommon.cpp b/src/zenhttp/clients/httpclientcommon.cpp
index 248ae9d70..9ded23375 100644
--- a/src/zenhttp/clients/httpclientcommon.cpp
+++ b/src/zenhttp/clients/httpclientcommon.cpp
@@ -394,31 +394,28 @@ namespace detail {
 			{
 				// Yes, we do a substring of the non-lowercase value string as we want the exact boundary string
 				std::string_view BoundaryName = std::string_view(ContentTypeHeaderValue).substr(BoundaryPos + 9);
+				size_t			 BoundaryEnd  = std::string::npos;
+				while (!BoundaryName.empty() && BoundaryName[0] == ' ')
+				{
+					BoundaryName = BoundaryName.substr(1);
+				}
 				if (!BoundaryName.empty())
 				{
-					size_t BoundaryEnd = std::string::npos;
-					while (BoundaryName[0] == ' ')
-					{
-						BoundaryName = BoundaryName.substr(1);
-					}
-					if (!BoundaryName.empty())
+					if (BoundaryName.size() > 2 && BoundaryName.front() == '"' && BoundaryName.back() == '"')
 					{
-						if (BoundaryName.size() > 2 && BoundaryName.front() == '"' && BoundaryName.back() == '"')
+						BoundaryEnd = BoundaryName.find('"', 1);
+						if (BoundaryEnd != std::string::npos)
 						{
-							BoundaryEnd = BoundaryName.find('"', 1);
-							if (BoundaryEnd != std::string::npos)
-							{
-								BoundaryBeginMatcher.Init(fmt::format("\r\n--{}", BoundaryName.substr(1, BoundaryEnd - 1)));
-								return true;
-							}
-						}
-						else
-						{
-							BoundaryEnd = BoundaryName.find_first_of(" \r\n");
-							BoundaryBeginMatcher.Init(fmt::format("\r\n--{}", BoundaryName.substr(0, BoundaryEnd)));
+							BoundaryBeginMatcher.Init(fmt::format("\r\n--{}", BoundaryName.substr(1, BoundaryEnd - 1)));
 							return true;
 						}
 					}
+					else
+					{
+						BoundaryEnd = BoundaryName.find_first_of(" \r\n");
+						BoundaryBeginMatcher.Init(fmt::format("\r\n--{}", BoundaryName.substr(0, BoundaryEnd)));
+						return true;
+					}
 				}
 			}
 		}
diff --git a/src/zenhttp/httpclient.cpp b/src/zenhttp/httpclient.cpp
index f94c58581..281d512cf 100644
--- a/src/zenhttp/httpclient.cpp
+++ b/src/zenhttp/httpclient.cpp
@@ -107,17 +107,14 @@ HttpClientBase::GetAccessToken()
 std::vector<std::pair<uint64_t, uint64_t>>
 HttpClient::Response::GetRanges(std::span<const std::pair<uint64_t, uint64_t>> OffsetAndLengthPairs) const
 {
-	std::vector<std::pair<uint64_t, uint64_t>> Result;
-	Result.reserve(OffsetAndLengthPairs.size());
 	if (Ranges.empty())
 	{
-		for (const std::pair<uint64_t, uint64_t>& Range : OffsetAndLengthPairs)
-		{
-			Result.emplace_back(std::make_pair(Range.first, Range.second));
-		}
-		return Result;
+		return {};
 	}
 
+	std::vector<std::pair<uint64_t, uint64_t>> Result;
+	Result.reserve(OffsetAndLengthPairs.size());
+
 	auto BoundaryIt			   = Ranges.begin();
 	auto OffsetAndLengthPairIt = OffsetAndLengthPairs.begin();
 	while (OffsetAndLengthPairIt != OffsetAndLengthPairs.end())
diff --git a/src/zenhttp/include/zenhttp/httpclient.h b/src/zenhttp/include/zenhttp/httpclient.h
index f00bbec63..53be36b9a 100644
--- a/src/zenhttp/include/zenhttp/httpclient.h
+++ b/src/zenhttp/include/zenhttp/httpclient.h
@@ -190,10 +190,12 @@ public:
 			HttpContentType ContentType;
 		};
 
-		// Ranges will map out all recevied ranges, both single and multi-range responses
+		// Ranges will map out all received ranges, both single and multi-range responses
 		// If no range was requested Ranges will be empty
 		std::vector<MultipartBoundary> Ranges;
 
+		// Map the absolute OffsetAndLengthPairs into ResponsePayload from the ranges received (Ranges).
+		// If the response was not a partial response, an empty vector will be returned
 		std::vector<std::pair<uint64_t, uint64_t>> GetRanges(std::span<const std::pair<uint64_t, uint64_t>> OffsetAndLengthPairs) const;
 
 		// This contains any errors from the HTTP stack. It won't contain information on