Add support for response files with vcpkg (#4507)

Response files are a convenient way of specifying bulk parameters,
typically supported by compilers and linkers. For vcpkg response files
provide a convenient way of installing sets of packages from simple
newline separate list files.

2 files changed, 22 insertions, 2 deletions

diff --git a/toolsrc/src/vcpkg/help.cpp b/toolsrc/src/vcpkg/help.cpp
index 2b409373d..5df878a91 100644
--- a/toolsrc/src/vcpkg/help.cpp
+++ b/toolsrc/src/vcpkg/help.cpp
@@ -116,6 +116,8 @@ namespace vcpkg::Help
             "  --vcpkg-root <path>             Specify the vcpkg root directory\n"
             "                                  (default: " ENVVAR(VCPKG_ROOT) ")\n"
             "\n"
+            "  @response_file                  Specify a response file to provide additional parameters\n"
+            "\n"
             "For more help (including examples) see the accompanying README.md.",
             Commands::Integrate::INTEGRATE_COMMAND_HELPSTRING);
     }
diff --git a/toolsrc/src/vcpkg/vcpkgcmdarguments.cpp b/toolsrc/src/vcpkg/vcpkgcmdarguments.cpp
index 8909e1552..5b3cf9ef1 100644
--- a/toolsrc/src/vcpkg/vcpkgcmdarguments.cpp
+++ b/toolsrc/src/vcpkg/vcpkgcmdarguments.cpp
@@ -51,11 +51,29 @@ namespace vcpkg
         std::vector<std::string> v;
         for (int i = 1; i < argc; ++i)
         {
+            std::string arg;
 #if defined(_WIN32)
-            v.push_back(Strings::to_utf8(argv[i]));
+            arg = Strings::to_utf8(argv[i]);
 #else
-            v.push_back(argv[i]);
+            arg = argv[i];
 #endif
+            // Response file?
+            if (arg.size() > 0 && arg[0] == '@')
+            {
+                arg.erase(arg.begin());
+                const auto& fs = Files::get_real_filesystem();
+                auto lines = fs.read_lines(fs::u8path(arg));
+                if (!lines.has_value())
+                {
+                    System::println(System::Color::error, "Error: Could not open response file %s", arg);
+                    Checks::exit_fail(VCPKG_LINE_INFO);
+                }
+                std::copy(lines.get()->begin(), lines.get()->end(), std::back_inserter(v));
+            }
+            else
+            {
+                v.emplace_back(std::move(arg));
+            }
         }
 
         return VcpkgCmdArguments::create_from_arg_sequence(v.data(), v.data() + v.size());