allow download specification for zen builds download (#734)

- Feature: `zen builds download` now supports `--download-spec-path` to determine what content to download from a build
  - The unstructured format expects one line per file relative to the root with '/' as a path delimiter
  - The structured format uses JSon format and the `--download-spec-path` must have extension `.json` to enable structured input

        {
            "parts": {
                "default" : {
                    "files": [
                        "foo/bar",
                        "baz.exe"
                    ]
                },
                "symbols": {
                    "files": [
                        "baz.pdb"
                    ]
                }
            }
        }

2 files changed, 30 insertions, 13 deletions

diff --git a/src/zenremotestore/include/zenremotestore/builds/buildmanifest.h b/src/zenremotestore/include/zenremotestore/builds/buildmanifest.h
new file mode 100644
index 000000000..a0d9a7691
--- /dev/null
+++ b/src/zenremotestore/include/zenremotestore/builds/buildmanifest.h
@@ -0,0 +1,27 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#pragma once
+
+#include <zencore/filesystem.h>
+#include <zencore/uid.h>
+
+namespace zen {
+
+struct BuildManifest
+{
+	struct Part
+	{
+		Oid								   PartId = Oid::Zero;
+		std::string						   PartName;
+		std::vector<std::filesystem::path> Files;
+	};
+	std::vector<Part> Parts;
+};
+
+BuildManifest ParseBuildManifest(const std::filesystem::path& ManifestPath);
+
+#if ZEN_WITH_TESTS
+void buildmanifest_forcelink();
+#endif	// ZEN_WITH_TESTS
+
+}  // namespace zen
diff --git a/src/zenremotestore/include/zenremotestore/builds/buildstorageoperations.h b/src/zenremotestore/include/zenremotestore/builds/buildstorageoperations.h
index 9f7d93398..47f402e15 100644
--- a/src/zenremotestore/include/zenremotestore/builds/buildstorageoperations.h
+++ b/src/zenremotestore/include/zenremotestore/builds/buildstorageoperations.h
@@ -577,17 +577,6 @@ private:
 
 	PrepareBuildResult PrepareBuild();
 
-	struct PartManifest
-	{
-		struct Part
-		{
-			Oid								   PartId;
-			std::string						   PartName;
-			std::vector<std::filesystem::path> Files;
-		};
-		std::vector<Part> Parts;
-	};
-
 	struct UploadPart
 	{
 		Oid						   PartId = Oid::Zero;
@@ -600,8 +589,6 @@ private:
 	std::vector<BuildsOperationUploadFolder::UploadPart> ReadFolder();
 	std::vector<UploadPart>								 ReadManifestParts(const std::filesystem::path& ManifestPath);
 
-	PartManifest ParseManifest(const std::filesystem::path& Path, const std::filesystem::path& ManifestPath);
-
 	bool IsAcceptedFolder(const std::string_view& RelativePath) const;
 	bool IsAcceptedFile(const std::string_view& RelativePath) const;
 
@@ -811,10 +798,13 @@ std::vector<std::pair<Oid, std::string>> ResolveBuildPartNames(CbObjectView
 															   std::span<const std::string> BuildPartNames,
 															   std::uint64_t&				OutPreferredMultipartChunkSize);
 
+struct BuildManifest;
+
 ChunkedFolderContent GetRemoteContent(OperationLogOutput&							  Output,
 									  StorageInstance&								  Storage,
 									  const Oid&									  BuildId,
 									  const std::vector<std::pair<Oid, std::string>>& BuildParts,
+									  const BuildManifest&							  Manifest,
 									  std::span<const std::string>					  IncludeWildcards,
 									  std::span<const std::string>					  ExcludeWildcards,
 									  std::unique_ptr<ChunkingController>&			  OutChunkController,