cmArchiveWrite: Consolidate multiple ways to set thread count

Merge use of SetFilterOption() into more abstract thread count
in cmArchiveWrite constructor.

libarchive defaulting of threads for threads == 0 seems to be
configuration dependent. Preemptively default thread count via
std::thread::hardware_concurrency().

Also allow negative values for the thread count in which case
the detected hardware concurrency is also used but the given
absolute thread count is used as an upper limit.

3 files changed, 12 insertions, 34 deletions

diff --git a/Source/CPack/cmCPackArchiveGenerator.cxx b/Source/CPack/cmCPackArchiveGenerator.cxx
index 7fd12dd..d9234e6 100644
--- a/Source/CPack/cmCPackArchiveGenerator.cxx
+++ b/Source/CPack/cmCPackArchiveGenerator.cxx
@@ -2,14 +2,13 @@
    file Copyright.txt or https://cmake.org/licensing for details.  */
 #include "cmCPackArchiveGenerator.h"
 
+#include <cstdlib>
 #include <cstring>
 #include <map>
 #include <ostream>
 #include <utility>
 #include <vector>
 
-#include <cm3p/archive.h>
-
 #include "cmCPackComponentGroup.h"
 #include "cmCPackGenerator.h"
 #include "cmCPackLog.h"
@@ -154,15 +153,9 @@ int cmCPackArchiveGenerator::addOneComponentToArchive(
                     << (filename) << ">." << std::endl);                      \
     return 0;                                                                 \
   }                                                                           \
-  cmArchiveWrite archive(gf, this->Compress, this->ArchiveFormat);            \
+  cmArchiveWrite archive(gf, this->Compress, this->ArchiveFormat, 0,          \
+                         this->GetThreadCount());                             \
   do {                                                                        \
-    if (!this->SetArchiveOptions(&archive)) {                                 \
-      cmCPackLogger(cmCPackLog::LOG_ERROR,                                    \
-                    "Problem to set archive options <"                        \
-                      << (filename) << ">, ERROR = " << (archive).GetError()  \
-                      << std::endl);                                          \
-      return 0;                                                               \
-    }                                                                         \
     if (!archive.Open()) {                                                    \
       cmCPackLogger(cmCPackLog::LOG_ERROR,                                    \
                     "Problem to open archive <"                               \
@@ -346,26 +339,16 @@ bool cmCPackArchiveGenerator::SupportsComponentInstallation() const
   return this->IsOn("CPACK_ARCHIVE_COMPONENT_INSTALL");
 }
 
-bool cmCPackArchiveGenerator::SetArchiveOptions(cmArchiveWrite* archive)
+int cmCPackArchiveGenerator::GetThreadCount() const
 {
-#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";
-
-    // CPACK_ARCHIVE_THREADS overrides CPACK_THREADS
-    if (this->IsSet("CPACK_ARCHIVE_THREADS")) {
-      threads = this->GetOption("CPACK_ARCHIVE_THREADS");
-    } else if (this->IsSet("CPACK_THREADS")) {
-      threads = this->GetOption("CPACK_THREADS");
-    }
+  int threads = 1;
 
-    if (!archive->SetFilterOption("xz", "threads", threads)) {
-      return false;
-    }
+  // CPACK_ARCHIVE_THREADS overrides CPACK_THREADS
+  if (this->IsSet("CPACK_ARCHIVE_THREADS")) {
+    threads = std::atoi(this->GetOption("CPACK_ARCHIVE_THREADS"));
+  } else if (this->IsSet("CPACK_THREADS")) {
+    threads = std::atoi(this->GetOption("CPACK_THREADS"));
   }
-#endif
 
-  return true;
+  return threads;
 }
diff --git a/Source/CPack/cmCPackArchiveGenerator.h b/Source/CPack/cmCPackArchiveGenerator.h
index 5b40013..8a9bbc6 100644
--- a/Source/CPack/cmCPackArchiveGenerator.h
+++ b/Source/CPack/cmCPackArchiveGenerator.h
@@ -85,7 +85,7 @@ private:
     return this->OutputExtension.c_str();
   }
 
-  bool SetArchiveOptions(cmArchiveWrite* archive);
+  int GetThreadCount() const;
 
 private:
   cmArchiveWrite::Compress Compress;
diff --git a/Source/CPack/cmCPackDebGenerator.cxx b/Source/CPack/cmCPackDebGenerator.cxx
index e7bcfac..0fafd85 100644
--- a/Source/CPack/cmCPackDebGenerator.cxx
+++ b/Source/CPack/cmCPackDebGenerator.cxx
@@ -130,11 +130,6 @@ DebGenerator::DebGenerator(
                   "Unrecognized number of threads: " << numThreads
                                                      << std::endl);
   }
-
-  if (this->NumThreads < 0) {
-    cmCPackLogger(cmCPackLog::LOG_ERROR,
-                  "Number of threads cannot be negative" << std::endl);
-  }
 }
 
 bool DebGenerator::generate() const