Install: Refactor ResolveTargetsInGeneratorExpression

Source/cmExportFileGenerator.cxx

@@ -4,10 +4,12 @@
 
 #include <array>
 #include <cstddef>
+#include <functional>
 #include <sstream>
 #include <utility>
 
 #include <cm/memory>
+#include <cm/optional>
 #include <cm/string_view>
 #include <cmext/string_view>
 
@@ -449,9 +451,9 @@ void cmExportFileGenerator::ResolveTargetsInGeneratorExpressions(
   }
 }
 
-void cmExportFileGenerator::ResolveTargetsInGeneratorExpression(
-  std::string& input, cmGeneratorTarget const* target,
-  cmLocalGenerator const* lg)
+cm::optional<std::string> cmResolveTargetsInGeneratorExpression(
+  std::string& input,
+  std::function<bool(std::string& name)> const& addTargetNamespace)
 {
   std::string::size_type pos = 0;
   std::string::size_type lastPos = pos;
@@ -474,7 +476,7 @@ void cmExportFileGenerator::ResolveTargetsInGeneratorExpression(
     std::string targetName =
       input.substr(nameStartPos, commaPos - nameStartPos);
 
-    if (this->AddTargetNamespace(targetName, target, lg)) {
+    if (addTargetNamespace(targetName)) {
       input.replace(nameStartPos, commaPos - nameStartPos, targetName);
     }
     lastPos = nameStartPos + targetName.size() + 1;
@@ -496,7 +498,7 @@ void cmExportFileGenerator::ResolveTargetsInGeneratorExpression(
                     "literal.";
       break;
     }
-    if (!this->AddTargetNamespace(targetName, target, lg)) {
+    if (!addTargetNamespace(targetName)) {
       errorString = "$<TARGET_NAME:...> requires its parameter to be a "
                     "reachable target.";
       break;
@@ -517,7 +519,7 @@ void cmExportFileGenerator::ResolveTargetsInGeneratorExpression(
     }
     std::string libName = input.substr(nameStartPos, endPos - nameStartPos);
     if (cmGeneratorExpression::IsValidTargetName(libName) &&
-        this->AddTargetNamespace(libName, target, lg)) {
+        addTargetNamespace(libName)) {
       input.replace(nameStartPos, endPos - nameStartPos, libName);
     }
     lastPos = nameStartPos + libName.size() + 1;
@@ -533,17 +535,29 @@ void cmExportFileGenerator::ResolveTargetsInGeneratorExpression(
     }
     std::string libName = input.substr(nameStartPos, endPos - nameStartPos);
     if (cmGeneratorExpression::IsValidTargetName(libName) &&
-        this->AddTargetNamespace(libName, target, lg)) {
+        addTargetNamespace(libName)) {
       input.replace(nameStartPos, endPos - nameStartPos, libName);
     }
     lastPos = nameStartPos + libName.size() + 1;
   }
 
-  this->ReplaceInstallPrefix(input);
-
   if (!errorString.empty()) {
-    target->GetLocalGenerator()->IssueMessage(MessageType::FATAL_ERROR,
-                                              errorString);
+    return errorString;
+  }
+  return cm::nullopt;
+}
+
+void cmExportFileGenerator::ResolveTargetsInGeneratorExpression(
+  std::string& input, cmGeneratorTarget const* target,
+  cmLocalGenerator const* lg)
+{
+  auto err = cmResolveTargetsInGeneratorExpression(
+    input, [this, target, lg](std::string& name) {
+      return this->AddTargetNamespace(name, target, lg);
+    });
+  this->ReplaceInstallPrefix(input);
+  if (err) {
+    target->GetLocalGenerator()->IssueMessage(MessageType::FATAL_ERROR, *err);
   }
 }
 

Source/cmExportFileGenerator.h

@@ -4,12 +4,14 @@
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
+#include <functional>
 #include <iosfwd>
 #include <map>
 #include <set>
 #include <string>
 #include <vector>
 
+#include <cm/optional>
 #include <cm/string_view>
 
 #include "cmDiagnostics.h"
@@ -238,3 +240,16 @@ extern template void cmExportFileGenerator::SetImportLinkProperty<cmLinkItem>(
   std::string const&, cmGeneratorTarget const*, std::string const&,
   std::vector<cmLinkItem> const&, ImportPropertyMap& properties,
   ImportLinkPropertyTargetNames);
+
+/** Walk a generator expression and rewrite the target-name slot of each
+    `$<TARGET_PROPERTY:>`, `$<TARGET_NAME:>`, `$<LINK_ONLY:>`, and
+    `$<COMPILE_ONLY:>` construct via the provided callback.  The callback
+    receives the bare target name; if it mutates the name and returns true,
+    the helper splices the new name back into the genex. Returns the
+    parse-level error message, if an error was encountered. Callers handle
+    install-prefix substitution and error reporting themselves. This is used
+    by the cmExportFileGenerator hierarchy, as well as the cmSbomBuilder
+    hierarchy.  */
+cm::optional<std::string> cmResolveTargetsInGeneratorExpression(
+  std::string& input,
+  std::function<bool(std::string& name)> const& addTargetNamespace);