cmCPackArchiveGenerator: support multithreaded compression

Help/cpack_gen/archive.rst

@@ -51,3 +51,25 @@ Variables specific to CPack Archive generator
   Enable component packaging. If enabled (ON), then the archive generator
   creates  multiple packages. The default is OFF, which means that a single
   package containing files of all components is generated.
+
+Variables used by CPack Archive generator
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+These variables are used by the Archive generator, but are also available to
+CPack generators which are essentially archives at their core. These include:
+
+  - :cpack_gen:`CPack Cygwin Generator`
+  - :cpack_gen:`CPack FreeBSD Generator`
+
+.. variable:: CPACK_ARCHIVE_THREADS
+
+  The number of threads to use when performing the compression. If set to
+  ``0``, the number of available cores on the machine will be used instead.
+  The default is ``1`` which limits compression to a single thread. Note that
+  not all compression modes support threading in all environments. Currently,
+  only the XZ compression may support it.
+
+.. note::
+
+    Official CMake binaries available on ``cmake.org`` ship with a ``liblzma``
+    that does not support parallel compression.

Help/cpack_gen/cygwin.rst

@@ -3,6 +3,11 @@ CPack Cygwin Generator
 
 Cygwin CPack generator (Cygwin).
 
+Variables affecting the CPack Cygwin generator
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+  - :variable:`CPACK_ARCHIVE_THREADS`
+
 Variables specific to CPack Cygwin generator
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 

Help/cpack_gen/freebsd.rst

@@ -3,6 +3,11 @@ CPack FreeBSD Generator
 
 The built in (binary) CPack FreeBSD (pkg) generator (Unix only)
 
+Variables affecting the CPack FreeBSD (pkg) generator
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+  - :variable:`CPACK_ARCHIVE_THREADS`
+
 Variables specific to CPack FreeBSD (pkg) generator
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 

Help/release/dev/parallel-lzma-compression.rst

@@ -0,0 +1,6 @@
+parallel-lzma-compression
+-------------------------
+
+* The :cpack_gen:`CPack Archive Generator`'s ``TXZ`` format learned the
+  :variable:`CPACK_ARCHIVE_THREADS` variable to enable parallel compression.
+  Requires support in the ``liblzma`` used by CMake.

Source/CPack/cmCPackArchiveGenerator.cxx

@@ -8,6 +8,8 @@
 #include <utility>
 #include <vector>
 
+#include "cm_libarchive.h"
+
 #include "cmCPackComponentGroup.h"
 #include "cmCPackGenerator.h"
 #include "cmCPackLog.h"
@@ -343,7 +345,22 @@ bool cmCPackArchiveGenerator::SupportsComponentInstallation() const
   return IsOn("CPACK_ARCHIVE_COMPONENT_INSTALL");
 }
 
-bool cmCPackArchiveGenerator::SetArchiveOptions(cmArchiveWrite* /*archive*/)
+bool cmCPackArchiveGenerator::SetArchiveOptions(cmArchiveWrite* archive)
 {
+#if ARCHIVE_VERSION_NUMBER >= 3004000
+  // Upstream fixed an issue with their integer parsing in 3.4.0 which would
+  // cause spurious errors to be raised from `strtoull`.
+  if (this->Compress == cmArchiveWrite::CompressXZ) {
+    const char* threads = "1";
+    if (this->IsSet("CPACK_ARCHIVE_THREADS")) {
+      threads = this->GetOption("CPACK_ARCHIVE_THREADS");
+    }
+
+    if (!archive->SetFilterOption("xz", "threads", threads)) {
+      return false;
+    }
+  }
+#endif
+
   return true;
 }

Tests/RunCMake/CPack/RunCMakeTest.cmake

@@ -20,6 +20,8 @@ run_cpack_test(LONG_FILENAMES "DEB.LONG_FILENAMES" false "MONOLITHIC")
 run_cpack_test_subtests(MAIN_COMPONENT "invalid;found" "RPM.MAIN_COMPONENT" false "COMPONENT")
 run_cpack_test(MINIMAL "RPM.MINIMAL;DEB.MINIMAL;7Z;TBZ2;TGZ;TXZ;TZ;ZIP;STGZ;External" false "MONOLITHIC;COMPONENT")
 run_cpack_test_package_target(MINIMAL "RPM.MINIMAL;DEB.MINIMAL;7Z;TBZ2;TGZ;TXZ;TZ;ZIP;STGZ;External" false "MONOLITHIC;COMPONENT")
+run_cpack_test_package_target(THREADED_ALL "TXZ" false "MONOLITHIC;COMPONENT")
+run_cpack_test_package_target(THREADED "TXZ" false "MONOLITHIC;COMPONENT")
 run_cpack_test_subtests(PACKAGE_CHECKSUM "invalid;MD5;SHA1;SHA224;SHA256;SHA384;SHA512" "TGZ" false "MONOLITHIC")
 run_cpack_test(PARTIALLY_RELOCATABLE_WARNING "RPM.PARTIALLY_RELOCATABLE_WARNING" false "COMPONENT")
 run_cpack_test(PER_COMPONENT_FIELDS "RPM.PER_COMPONENT_FIELDS;DEB.PER_COMPONENT_FIELDS" false "COMPONENT")

Tests/RunCMake/CPack/tests/THREADED/ExpectedFiles.cmake

@@ -0,0 +1,2 @@
+set(EXPECTED_FILES_COUNT "1")
+set(EXPECTED_FILE_CONTENT_1_LIST "/foo;/foo/CMakeLists.txt")

Tests/RunCMake/CPack/tests/THREADED/test.cmake

@@ -0,0 +1,7 @@
+install(FILES CMakeLists.txt DESTINATION foo COMPONENT test)
+
+set(CPACK_ARCHIVE_THREADS 2)
+
+if(PACKAGING_TYPE STREQUAL "COMPONENT")
+  set(CPACK_COMPONENTS_ALL test)
+endif()

Tests/RunCMake/CPack/tests/THREADED_ALL/ExpectedFiles.cmake

@@ -0,0 +1,2 @@
+set(EXPECTED_FILES_COUNT "1")
+set(EXPECTED_FILE_CONTENT_1_LIST "/foo;/foo/CMakeLists.txt")

Tests/RunCMake/CPack/tests/THREADED_ALL/test.cmake

@@ -0,0 +1,7 @@
+install(FILES CMakeLists.txt DESTINATION foo COMPONENT test)
+
+set(CPACK_ARCHIVE_THREADS 0)
+
+if(PACKAGING_TYPE STREQUAL "COMPONENT")
+  set(CPACK_COMPONENTS_ALL test)
+endif()