cmDyndepCollation: factor out writing C++ module info from Ninja

To facilitate other generators being able to build C++20 modules, start
pulling out collator logic into a generator-agnostic location.

This commit starts by factoring out the information written to the
"target depend info" object consumed during the build to handle writing
out export and installation scripts expected during those steps.

4 files changed, 303 insertions, 214 deletions

diff --git a/Source/CMakeLists.txt b/Source/CMakeLists.txt
index c0709c6..41a901a 100644
--- a/Source/CMakeLists.txt
+++ b/Source/CMakeLists.txt
@@ -198,6 +198,8 @@ add_library(
   cmDocumentationFormatter.cxx
   cmDynamicLoader.cxx
   cmDynamicLoader.h
+  cmDyndepCollation.cxx
+  cmDyndepCollation.h
   cmELF.h
   cmELF.cxx
   cmExprParserHelper.cxx
diff --git a/Source/cmDyndepCollation.cxx b/Source/cmDyndepCollation.cxx
new file mode 100644
index 0000000..92ad697
--- /dev/null
+++ b/Source/cmDyndepCollation.cxx
@@ -0,0 +1,262 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+
+#include "cmDyndepCollation.h"
+
+#include <algorithm>
+#include <map>
+#include <memory>
+#include <utility>
+#include <vector>
+
+#include <cm/string_view>
+#include <cmext/string_view>
+
+#include <cm3p/json/value.h>
+
+#include "cmExportBuildFileGenerator.h"
+#include "cmExportSet.h"
+#include "cmFileSet.h"
+#include "cmGeneratorExpression.h" // IWYU pragma: keep
+#include "cmGeneratorTarget.h"
+#include "cmGlobalGenerator.h"
+#include "cmInstallCxxModuleBmiGenerator.h"
+#include "cmInstallExportGenerator.h"
+#include "cmInstallFileSetGenerator.h"
+#include "cmInstallGenerator.h"
+#include "cmMakefile.h"
+#include "cmMessageType.h"
+#include "cmSourceFile.h"
+#include "cmStringAlgorithms.h"
+#include "cmSystemTools.h"
+#include "cmTarget.h"
+#include "cmTargetExport.h"
+
+namespace {
+
+Json::Value CollationInformationCxxModules(
+  cmGeneratorTarget const* gt, std::string const& config,
+  cmDyndepGeneratorCallbacks const& cb)
+{
+  cmTarget const* tgt = gt->Target;
+  auto all_file_sets = tgt->GetAllFileSetNames();
+  Json::Value tdi_cxx_module_info = Json::objectValue;
+  for (auto const& file_set_name : all_file_sets) {
+    auto const* file_set = tgt->GetFileSet(file_set_name);
+    if (!file_set) {
+      gt->Makefile->IssueMessage(MessageType::INTERNAL_ERROR,
+                                 cmStrCat("Target \"", tgt->GetName(),
+                                          "\" is tracked to have file set \"",
+                                          file_set_name,
+                                          "\", but it was not found."));
+      continue;
+    }
+    auto fs_type = file_set->GetType();
+    // We only care about C++ module sources here.
+    if (fs_type != "CXX_MODULES"_s) {
+      continue;
+    }
+
+    auto fileEntries = file_set->CompileFileEntries();
+    auto directoryEntries = file_set->CompileDirectoryEntries();
+
+    auto directories = file_set->EvaluateDirectoryEntries(
+      directoryEntries, gt->LocalGenerator, config, gt);
+    std::map<std::string, std::vector<std::string>> files_per_dirs;
+    for (auto const& entry : fileEntries) {
+      file_set->EvaluateFileEntry(directories, files_per_dirs, entry,
+                                  gt->LocalGenerator, config, gt);
+    }
+
+    std::map<std::string, cmSourceFile const*> sf_map;
+    {
+      std::vector<cmSourceFile const*> objectSources;
+      gt->GetObjectSources(objectSources, config);
+      for (auto const* sf : objectSources) {
+        auto full_path = sf->GetFullPath();
+        if (full_path.empty()) {
+          gt->Makefile->IssueMessage(
+            MessageType::INTERNAL_ERROR,
+            cmStrCat("Target \"", tgt->GetName(),
+                     "\" has a full path-less source file."));
+          continue;
+        }
+        sf_map[full_path] = sf;
+      }
+    }
+
+    Json::Value fs_dest = Json::nullValue;
+    for (auto const& ig : gt->Makefile->GetInstallGenerators()) {
+      if (auto const* fsg =
+            dynamic_cast<cmInstallFileSetGenerator const*>(ig.get())) {
+        if (fsg->GetTarget() == gt && fsg->GetFileSet() == file_set) {
+          fs_dest = fsg->GetDestination(config);
+          continue;
+        }
+      }
+    }
+
+    for (auto const& files_per_dir : files_per_dirs) {
+      for (auto const& file : files_per_dir.second) {
+        auto lookup = sf_map.find(file);
+        if (lookup == sf_map.end()) {
+          gt->Makefile->IssueMessage(
+            MessageType::INTERNAL_ERROR,
+            cmStrCat("Target \"", tgt->GetName(), "\" has source file \"",
+                     file,
+                     R"(" which is not in any of its "FILE_SET BASE_DIRS".)"));
+          continue;
+        }
+
+        auto const* sf = lookup->second;
+
+        if (!sf) {
+          gt->Makefile->IssueMessage(
+            MessageType::INTERNAL_ERROR,
+            cmStrCat("Target \"", tgt->GetName(), "\" has source file \"",
+                     file, "\" which has not been tracked properly."));
+          continue;
+        }
+
+        auto obj_path = cb.ObjectFilePath(sf, config);
+        Json::Value& tdi_module_info = tdi_cxx_module_info[obj_path] =
+          Json::objectValue;
+
+        tdi_module_info["source"] = file;
+        tdi_module_info["relative-directory"] = files_per_dir.first;
+        tdi_module_info["name"] = file_set->GetName();
+        tdi_module_info["type"] = file_set->GetType();
+        tdi_module_info["visibility"] =
+          std::string(cmFileSetVisibilityToName(file_set->GetVisibility()));
+        tdi_module_info["destination"] = fs_dest;
+      }
+    }
+  }
+
+  return tdi_cxx_module_info;
+}
+
+Json::Value CollationInformationBmiInstallation(cmGeneratorTarget const* gt,
+                                                std::string const& config)
+{
+  cmInstallCxxModuleBmiGenerator const* bmi_gen = nullptr;
+  for (auto const& ig : gt->Makefile->GetInstallGenerators()) {
+    if (auto const* bmig =
+          dynamic_cast<cmInstallCxxModuleBmiGenerator const*>(ig.get())) {
+      if (bmig->GetTarget() == gt) {
+        bmi_gen = bmig;
+        continue;
+      }
+    }
+  }
+  if (bmi_gen) {
+    Json::Value tdi_bmi_info = Json::objectValue;
+
+    tdi_bmi_info["permissions"] = bmi_gen->GetFilePermissions();
+    tdi_bmi_info["destination"] = bmi_gen->GetDestination(config);
+    const char* msg_level = "";
+    switch (bmi_gen->GetMessageLevel()) {
+      case cmInstallGenerator::MessageDefault:
+        break;
+      case cmInstallGenerator::MessageAlways:
+        msg_level = "MESSAGE_ALWAYS";
+        break;
+      case cmInstallGenerator::MessageLazy:
+        msg_level = "MESSAGE_LAZY";
+        break;
+      case cmInstallGenerator::MessageNever:
+        msg_level = "MESSAGE_NEVER";
+        break;
+    }
+    tdi_bmi_info["message-level"] = msg_level;
+    tdi_bmi_info["script-location"] = bmi_gen->GetScriptLocation(config);
+
+    return tdi_bmi_info;
+  }
+  return Json::nullValue;
+}
+
+Json::Value CollationInformationExports(cmGeneratorTarget const* gt)
+{
+  Json::Value tdi_exports = Json::arrayValue;
+  std::string export_name = gt->GetExportName();
+
+  auto const& all_install_exports = gt->GetGlobalGenerator()->GetExportSets();
+  for (auto const& exp : all_install_exports) {
+    // Ignore exports sets which are not for this target.
+    auto const& targets = exp.second.GetTargetExports();
+    auto tgt_export =
+      std::find_if(targets.begin(), targets.end(),
+                   [gt](std::unique_ptr<cmTargetExport> const& te) {
+                     return te->Target == gt;
+                   });
+    if (tgt_export == targets.end()) {
+      continue;
+    }
+
+    auto const* installs = exp.second.GetInstallations();
+    for (auto const* install : *installs) {
+      Json::Value tdi_export_info = Json::objectValue;
+
+      auto const& ns = install->GetNamespace();
+      auto const& dest = install->GetDestination();
+      auto const& cxxm_dir = install->GetCxxModuleDirectory();
+      auto const& export_prefix = install->GetTempDir();
+
+      tdi_export_info["namespace"] = ns;
+      tdi_export_info["export-name"] = export_name;
+      tdi_export_info["destination"] = dest;
+      tdi_export_info["cxx-module-info-dir"] = cxxm_dir;
+      tdi_export_info["export-prefix"] = export_prefix;
+      tdi_export_info["install"] = true;
+
+      tdi_exports.append(tdi_export_info);
+    }
+  }
+
+  auto const& all_build_exports = gt->Makefile->GetExportBuildFileGenerators();
+  for (auto const& exp : all_build_exports) {
+    std::vector<std::string> targets;
+    exp->GetTargets(targets);
+
+    // Ignore exports sets which are not for this target.
+    auto const& name = gt->GetName();
+    bool has_current_target =
+      std::any_of(targets.begin(), targets.end(),
+                  [name](std::string const& tname) { return tname == name; });
+    if (!has_current_target) {
+      continue;
+    }
+
+    Json::Value tdi_export_info = Json::objectValue;
+
+    auto const& ns = exp->GetNamespace();
+    auto const& main_fn = exp->GetMainExportFileName();
+    auto const& cxxm_dir = exp->GetCxxModuleDirectory();
+    auto dest = cmsys::SystemTools::GetParentDirectory(main_fn);
+    auto const& export_prefix =
+      cmSystemTools::GetFilenamePath(exp->GetMainExportFileName());
+
+    tdi_export_info["namespace"] = ns;
+    tdi_export_info["export-name"] = export_name;
+    tdi_export_info["destination"] = dest;
+    tdi_export_info["cxx-module-info-dir"] = cxxm_dir;
+    tdi_export_info["export-prefix"] = export_prefix;
+    tdi_export_info["install"] = false;
+
+    tdi_exports.append(tdi_export_info);
+  }
+
+  return tdi_exports;
+}
+}
+
+void cmDyndepCollation::AddCollationInformation(
+  Json::Value& tdi, cmGeneratorTarget const* gt, std::string const& config,
+  cmDyndepGeneratorCallbacks const& cb)
+{
+  tdi["cxx-modules"] = CollationInformationCxxModules(gt, config, cb);
+  tdi["bmi-installation"] = CollationInformationBmiInstallation(gt, config);
+  tdi["exports"] = CollationInformationExports(gt);
+  tdi["config"] = config;
+}
diff --git a/Source/cmDyndepCollation.h b/Source/cmDyndepCollation.h
new file mode 100644
index 0000000..088a3a0
--- /dev/null
+++ b/Source/cmDyndepCollation.h
@@ -0,0 +1,29 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+#pragma once
+
+#include "cmConfigure.h" // IWYU pragma: keep
+
+#include <functional>
+#include <string>
+
+class cmGeneratorTarget;
+class cmSourceFile;
+
+namespace Json {
+class Value;
+}
+
+struct cmDyndepGeneratorCallbacks
+{
+  std::function<std::string(cmSourceFile const* sf, std::string const& config)>
+    ObjectFilePath;
+};
+
+struct cmDyndepCollation
+{
+  static void AddCollationInformation(Json::Value& tdi,
+                                      cmGeneratorTarget const* gt,
+                                      std::string const& config,
+                                      cmDyndepGeneratorCallbacks const& cb);
+};
diff --git a/Source/cmNinjaTargetGenerator.cxx b/Source/cmNinjaTargetGenerator.cxx
index 095bf40..85a6fc2 100644
--- a/Source/cmNinjaTargetGenerator.cxx
+++ b/Source/cmNinjaTargetGenerator.cxx
@@ -4,6 +4,7 @@
 
 #include <algorithm>
 #include <cassert>
+#include <functional>
 #include <iterator>
 #include <map>
 #include <ostream>
@@ -21,17 +22,12 @@
 
 #include "cmComputeLinkInformation.h"
 #include "cmCustomCommandGenerator.h"
-#include "cmExportBuildFileGenerator.h"
-#include "cmExportSet.h"
+#include "cmDyndepCollation.h"
 #include "cmFileSet.h"
 #include "cmGeneratedFileStream.h"
 #include "cmGeneratorExpression.h"
 #include "cmGeneratorTarget.h"
 #include "cmGlobalNinjaGenerator.h"
-#include "cmInstallCxxModuleBmiGenerator.h"
-#include "cmInstallExportGenerator.h"
-#include "cmInstallFileSetGenerator.h"
-#include "cmInstallGenerator.h"
 #include "cmLocalGenerator.h"
 #include "cmLocalNinjaGenerator.h"
 #include "cmMakefile.h"
@@ -47,7 +43,6 @@
 #include "cmStringAlgorithms.h"
 #include "cmSystemTools.h"
 #include "cmTarget.h"
-#include "cmTargetExport.h"
 #include "cmValue.h"
 #include "cmake.h"
 
@@ -1637,214 +1632,15 @@ void cmNinjaTargetGenerator::WriteTargetDependInfo(std::string const& lang,
     tdi_linked_target_dirs.append(l);
   }
 
-  cmTarget* tgt = this->GeneratorTarget->Target;
-  auto all_file_sets = tgt->GetAllFileSetNames();
-  Json::Value& tdi_cxx_module_info = tdi["cxx-modules"] = Json::objectValue;
-  for (auto const& file_set_name : all_file_sets) {
-    auto* file_set = tgt->GetFileSet(file_set_name);
-    if (!file_set) {
-      this->GetMakefile()->IssueMessage(
-        MessageType::INTERNAL_ERROR,
-        cmStrCat("Target \"", tgt->GetName(),
-                 "\" is tracked to have file set \"", file_set_name,
-                 "\", but it was not found."));
-      continue;
-    }
-    auto fs_type = file_set->GetType();
-    // We only care about C++ module sources here.
-    if (fs_type != "CXX_MODULES"_s) {
-      continue;
-    }
-
-    auto fileEntries = file_set->CompileFileEntries();
-    auto directoryEntries = file_set->CompileDirectoryEntries();
-
-    auto directories = file_set->EvaluateDirectoryEntries(
-      directoryEntries, this->GeneratorTarget->LocalGenerator, config,
-      this->GeneratorTarget);
-    std::map<std::string, std::vector<std::string>> files_per_dirs;
-    for (auto const& entry : fileEntries) {
-      file_set->EvaluateFileEntry(directories, files_per_dirs, entry,
-                                  this->GeneratorTarget->LocalGenerator,
-                                  config, this->GeneratorTarget);
-    }
-
-    std::map<std::string, cmSourceFile const*> sf_map;
-    {
-      std::vector<cmSourceFile const*> objectSources;
-      this->GeneratorTarget->GetObjectSources(objectSources, config);
-      for (auto const* sf : objectSources) {
-        auto full_path = sf->GetFullPath();
-        if (full_path.empty()) {
-          this->GetMakefile()->IssueMessage(
-            MessageType::INTERNAL_ERROR,
-            cmStrCat("Target \"", tgt->GetName(),
-                     "\" has a full path-less source file."));
-          continue;
-        }
-        sf_map[full_path] = sf;
-      }
-    }
-
-    Json::Value fs_dest = Json::nullValue;
-    for (auto const& ig : this->GetMakefile()->GetInstallGenerators()) {
-      if (auto const* fsg =
-            dynamic_cast<cmInstallFileSetGenerator const*>(ig.get())) {
-        if (fsg->GetTarget() == this->GeneratorTarget &&
-            fsg->GetFileSet() == file_set) {
-          fs_dest = fsg->GetDestination(config);
-          continue;
-        }
-      }
-    }
-
-    for (auto const& files_per_dir : files_per_dirs) {
-      for (auto const& file : files_per_dir.second) {
-        auto lookup = sf_map.find(file);
-        if (lookup == sf_map.end()) {
-          this->GetMakefile()->IssueMessage(
-            MessageType::INTERNAL_ERROR,
-            cmStrCat("Target \"", tgt->GetName(), "\" has source file \"",
-                     file,
-                     R"(" which is not in any of its "FILE_SET BASE_DIRS".)"));
-          continue;
-        }
-
-        auto const* sf = lookup->second;
-
-        if (!sf) {
-          this->GetMakefile()->IssueMessage(
-            MessageType::INTERNAL_ERROR,
-            cmStrCat("Target \"", tgt->GetName(), "\" has source file \"",
-                     file, "\" which has not been tracked properly."));
-          continue;
-        }
-
-        auto obj_path = this->GetObjectFilePath(sf, config);
-        Json::Value& tdi_module_info = tdi_cxx_module_info[obj_path] =
-          Json::objectValue;
-
-        tdi_module_info["source"] = file;
-        tdi_module_info["relative-directory"] = files_per_dir.first;
-        tdi_module_info["name"] = file_set->GetName();
-        tdi_module_info["type"] = file_set->GetType();
-        tdi_module_info["visibility"] =
-          std::string(cmFileSetVisibilityToName(file_set->GetVisibility()));
-        tdi_module_info["destination"] = fs_dest;
-      }
-    }
-  }
-
-  tdi["config"] = config;
+  cmDyndepGeneratorCallbacks cb;
+  cb.ObjectFilePath = [this](cmSourceFile const* sf, std::string const& cnf) {
+    return this->GetObjectFilePath(sf, cnf);
+  };
 
-  // Add information about the export sets that this target is a member of.
-  Json::Value& tdi_exports = tdi["exports"] = Json::arrayValue;
-  std::string export_name = this->GeneratorTarget->GetExportName();
-
-  cmInstallCxxModuleBmiGenerator const* bmi_gen = nullptr;
-  for (auto const& ig : this->GetMakefile()->GetInstallGenerators()) {
-    if (auto const* bmig =
-          dynamic_cast<cmInstallCxxModuleBmiGenerator const*>(ig.get())) {
-      if (bmig->GetTarget() == this->GeneratorTarget) {
-        bmi_gen = bmig;
-        continue;
-      }
-    }
-  }
-  if (bmi_gen) {
-    Json::Value tdi_bmi_info = Json::objectValue;
-
-    tdi_bmi_info["permissions"] = bmi_gen->GetFilePermissions();
-    tdi_bmi_info["destination"] = bmi_gen->GetDestination(config);
-    const char* msg_level = "";
-    switch (bmi_gen->GetMessageLevel()) {
-      case cmInstallGenerator::MessageDefault:
-        break;
-      case cmInstallGenerator::MessageAlways:
-        msg_level = "MESSAGE_ALWAYS";
-        break;
-      case cmInstallGenerator::MessageLazy:
-        msg_level = "MESSAGE_LAZY";
-        break;
-      case cmInstallGenerator::MessageNever:
-        msg_level = "MESSAGE_NEVER";
-        break;
-    }
-    tdi_bmi_info["message-level"] = msg_level;
-    tdi_bmi_info["script-location"] = bmi_gen->GetScriptLocation(config);
-
-    tdi["bmi-installation"] = tdi_bmi_info;
-  } else {
-    tdi["bmi-installation"] = Json::nullValue;
-  }
-
-  auto const& all_install_exports =
-    this->GetGlobalGenerator()->GetExportSets();
-  for (auto const& exp : all_install_exports) {
-    // Ignore exports sets which are not for this target.
-    auto const& targets = exp.second.GetTargetExports();
-    auto tgt_export =
-      std::find_if(targets.begin(), targets.end(),
-                   [this](std::unique_ptr<cmTargetExport> const& te) {
-                     return te->Target == this->GeneratorTarget;
-                   });
-    if (tgt_export == targets.end()) {
-      continue;
-    }
-
-    auto const* installs = exp.second.GetInstallations();
-    for (auto const* install : *installs) {
-      Json::Value tdi_export_info = Json::objectValue;
-
-      auto const& ns = install->GetNamespace();
-      auto const& dest = install->GetDestination();
-      auto const& cxxm_dir = install->GetCxxModuleDirectory();
-      auto const& export_prefix = install->GetTempDir();
-
-      tdi_export_info["namespace"] = ns;
-      tdi_export_info["export-name"] = export_name;
-      tdi_export_info["destination"] = dest;
-      tdi_export_info["cxx-module-info-dir"] = cxxm_dir;
-      tdi_export_info["export-prefix"] = export_prefix;
-      tdi_export_info["install"] = true;
-
-      tdi_exports.append(tdi_export_info);
-    }
-  }
-
-  auto const& all_build_exports =
-    this->GetMakefile()->GetExportBuildFileGenerators();
-  for (auto const& exp : all_build_exports) {
-    std::vector<std::string> targets;
-    exp->GetTargets(targets);
-
-    // Ignore exports sets which are not for this target.
-    auto const& name = this->GeneratorTarget->GetName();
-    bool has_current_target =
-      std::any_of(targets.begin(), targets.end(),
-                  [name](std::string const& tname) { return tname == name; });
-    if (!has_current_target) {
-      continue;
-    }
-
-    Json::Value tdi_export_info = Json::objectValue;
-
-    auto const& ns = exp->GetNamespace();
-    auto const& main_fn = exp->GetMainExportFileName();
-    auto const& cxxm_dir = exp->GetCxxModuleDirectory();
-    auto dest = cmsys::SystemTools::GetParentDirectory(main_fn);
-    auto const& export_prefix =
-      cmSystemTools::GetFilenamePath(exp->GetMainExportFileName());
-
-    tdi_export_info["namespace"] = ns;
-    tdi_export_info["export-name"] = export_name;
-    tdi_export_info["destination"] = dest;
-    tdi_export_info["cxx-module-info-dir"] = cxxm_dir;
-    tdi_export_info["export-prefix"] = export_prefix;
-    tdi_export_info["install"] = false;
-
-    tdi_exports.append(tdi_export_info);
-  }
+#if !defined(CMAKE_BOOTSTRAP)
+  cmDyndepCollation::AddCollationInformation(tdi, this->GeneratorTarget,
+                                             config, cb);
+#endif
 
   std::string const tdin = this->GetTargetDependInfoPath(lang, config);
   cmGeneratedFileStream tdif(tdin);