CPS: Refactor ForbidGeneratorExpressions into cmGeneratorExpression

Source/cmExportPackageInfoGenerator.cxx

@@ -2,7 +2,6 @@
    file LICENSE.rst or https://cmake.org/licensing for details.  */
 #include "cmExportPackageInfoGenerator.h"
 
-#include <cstddef>
 #include <memory>
 #include <set>
 #include <utility>
@@ -295,51 +294,6 @@ bool cmExportPackageInfoGenerator::GenerateInterfaceProperties(
   return result;
 }
 
-namespace {
-bool ForbidGeneratorExpressions(
-  cmGeneratorTarget const* target, std::string const& propertyName,
-  std::string const& propertyValue, std::string& evaluatedValue,
-  std::map<std::string, std::vector<std::string>>& allowList)
-{
-  size_t const allowedExpressions = allowList.size();
-  evaluatedValue = cmGeneratorExpression::Collect(propertyValue, allowList);
-  if (evaluatedValue != propertyValue &&
-      allowList.size() > allowedExpressions) {
-    target->Makefile->IssueMessage(
-      MessageType::FATAL_ERROR,
-      cmStrCat("Property \"", propertyName, "\" of target \"",
-               target->GetName(),
-               "\" contains a generator expression. This is not allowed."));
-    return false;
-  }
-  // Forbid Nested Generator Expressions
-  for (auto const& genexp : allowList) {
-    for (auto const& value : genexp.second) {
-      if (value.find("$<") != std::string::npos) {
-        target->Makefile->IssueMessage(
-          MessageType::FATAL_ERROR,
-          cmStrCat(
-            "$<", genexp.first, ":...> expression in \"", propertyName,
-            "\" of target \"", target->GetName(),
-            "\" contains a generator expression. This is not allowed."));
-        return false;
-      }
-    }
-  }
-  return true;
-}
-
-bool ForbidGeneratorExpressions(cmGeneratorTarget const* target,
-                                std::string const& propertyName,
-                                std::string const& propertyValue)
-{
-  std::map<std::string, std::vector<std::string>> allowList;
-  std::string evaluatedValue;
-  return ForbidGeneratorExpressions(target, propertyName, propertyValue,
-                                    evaluatedValue, allowList);
-}
-}
-
 bool cmExportPackageInfoGenerator::NoteLinkedTarget(
   cmGeneratorTarget const* target, std::string const& linkedName,
   cmGeneratorTarget const* linkedTarget)
@@ -446,8 +400,9 @@ void cmExportPackageInfoGenerator::GenerateInterfaceLinkProperties(
   std::map<std::string, std::vector<std::string>> allowList = { { "LINK_ONLY",
                                                                   {} } };
   std::string interfaceLinkLibraries;
-  if (!ForbidGeneratorExpressions(target, iter->first, iter->second,
-                                  interfaceLinkLibraries, allowList)) {
+  if (!cmGeneratorExpression::ForbidGeneratorExpressions(
+        target, iter->first, iter->second, interfaceLinkLibraries,
+        allowList)) {
     result = false;
     return;
   }
@@ -490,7 +445,8 @@ void cmExportPackageInfoGenerator::GenerateInterfaceCompileFeatures(
     return;
   }
 
-  if (!ForbidGeneratorExpressions(target, iter->first, iter->second)) {
+  if (!cmGeneratorExpression::ForbidGeneratorExpressions(target, iter->first,
+                                                         iter->second)) {
     result = false;
     return;
   }
@@ -519,7 +475,8 @@ void cmExportPackageInfoGenerator::GenerateInterfaceCompileDefines(
   }
 
   // TODO: Support language-specific defines.
-  if (!ForbidGeneratorExpressions(target, iter->first, iter->second)) {
+  if (!cmGeneratorExpression::ForbidGeneratorExpressions(target, iter->first,
+                                                         iter->second)) {
     result = false;
     return;
   }
@@ -550,7 +507,8 @@ void cmExportPackageInfoGenerator::GenerateInterfaceListProperty(
     return;
   }
 
-  if (!ForbidGeneratorExpressions(target, prop, iter->second)) {
+  if (!cmGeneratorExpression::ForbidGeneratorExpressions(target, prop,
+                                                         iter->second)) {
     result = false;
     return;
   }
@@ -571,7 +529,8 @@ void cmExportPackageInfoGenerator::GenerateProperty(
     return;
   }
 
-  if (!ForbidGeneratorExpressions(target, inName, iter->second)) {
+  if (!cmGeneratorExpression::ForbidGeneratorExpressions(target, inName,
+                                                         iter->second)) {
     result = false;
     return;
   }

Source/cmGeneratorExpression.cxx

@@ -4,6 +4,7 @@
 
 #include <algorithm>
 #include <cassert>
+#include <cstddef>
 #include <memory>
 #include <stack>
 #include <utility>
@@ -18,8 +19,11 @@
 #include "cmGeneratorExpressionEvaluator.h"
 #include "cmGeneratorExpressionLexer.h"
 #include "cmGeneratorExpressionParser.h"
+#include "cmGeneratorTarget.h"
 #include "cmList.h"
 #include "cmLocalGenerator.h"
+#include "cmMakefile.h"
+#include "cmMessageType.h"
 #include "cmStringAlgorithms.h"
 #include "cmSystemTools.h"
 #include "cmake.h"
@@ -414,6 +418,50 @@ std::string cmGeneratorExpression::Collect(
   return extractAllGeneratorExpressions(input, &collected);
 }
 
+bool cmGeneratorExpression::ForbidGeneratorExpressions(
+  cmGeneratorTarget const* target, std::string const& propertyName,
+  std::string const& propertyValue)
+{
+  std::map<std::string, std::vector<std::string>> allowList;
+  std::string evaluatedValue;
+  return ForbidGeneratorExpressions(target, propertyName, propertyValue,
+                                    evaluatedValue, allowList);
+}
+
+bool cmGeneratorExpression::ForbidGeneratorExpressions(
+  cmGeneratorTarget const* target, std::string const& propertyName,
+  std::string const& propertyValue, std::string& evaluatedValue,
+  std::map<std::string, std::vector<std::string>>& allowList)
+{
+  size_t const initialAllowedGenExps = allowList.size();
+  evaluatedValue = Collect(propertyValue, allowList);
+  if (evaluatedValue != propertyValue &&
+      allowList.size() > initialAllowedGenExps) {
+    target->Makefile->IssueMessage(
+      MessageType::FATAL_ERROR,
+      cmStrCat("Property \"", propertyName, "\" of target \"",
+               target->GetName(),
+               "\" contains a generator expression. This is not allowed."));
+    return false;
+  }
+
+  // Check for nested generator expressions (e.g., $<LINK_ONLY:$<...>>).
+  for (auto const& genexp : allowList) {
+    for (auto const& value : genexp.second) {
+      if (value.find("$<") != std::string::npos) {
+        target->Makefile->IssueMessage(
+          MessageType::FATAL_ERROR,
+          cmStrCat("$<", genexp.first, ":...> expression in \"", propertyName,
+                   "\" of target \"", target->GetName(),
+                   "\" contains a generator expression. This is not "
+                   "allowed."));
+        return false;
+      }
+    }
+  }
+  return true;
+}
+
 cm::string_view::size_type cmGeneratorExpression::Find(cm::string_view input)
 {
   cm::string_view::size_type const openpos = input.find("$<");

Source/cmGeneratorExpression.h

@@ -58,6 +58,15 @@ public:
     cmGeneratorTarget const* currentTarget = nullptr,
     std::string const& language = std::string());
 
+  static bool ForbidGeneratorExpressions(
+    cmGeneratorTarget const* target, std::string const& propertyName,
+    std::string const& propertyValue, std::string& evaluatedValue,
+    std::map<std::string, std::vector<std::string>>& allowList);
+
+  static bool ForbidGeneratorExpressions(cmGeneratorTarget const* target,
+                                         std::string const& propertyName,
+                                         std::string const& propertyValue);
+
   enum PreprocessContext
   {
     StripAllGeneratorExpressions,