cmMakefile: store the number of last matches in a CMake var

With PushScope and PopScope, keeping track of another bit of data for
each scope isn't easy. Instead, store it as another CMake variable so it
gets implicitly tracked along with everything else.

This works in a revert of commit
7d674b5f0b.

Help/manual/cmake-variables.7.rst

@@ -47,6 +47,7 @@ Variables that Provide Information
    /variable/CMAKE_LINK_LIBRARY_SUFFIX
    /variable/CMAKE_MAJOR_VERSION
    /variable/CMAKE_MAKE_PROGRAM
+   /variable/CMAKE_MATCH_COUNT
    /variable/CMAKE_MINIMUM_REQUIRED_VERSION
    /variable/CMAKE_MINOR_VERSION
    /variable/CMAKE_PARENT_LIST_FILE

Help/release/dev/cached-regex-clear-fixed.rst

@@ -0,0 +1,5 @@
+cached-regex-clear-fixed
+------------------------
+
+* Add :variable:`CMAKE_MATCH_COUNT` for the number of matches made in the last
+  regular expression.

Help/variable/CMAKE_MATCH_COUNT.rst

@@ -0,0 +1,8 @@
+CMAKE_MATCH_COUNT
+-----------------
+
+The number of matches with the last regular expression.
+
+When a regular expression match is used, CMake fills in ``CMAKE_MATCH_<n>``
+variables with the match contents. The ``CMAKE_MATCH_COUNT`` variable holds
+the number of match expressions when these are filled.

Source/cmConditionEvaluator.cxx

@@ -11,7 +11,6 @@
 ============================================================================*/
 
 #include "cmConditionEvaluator.h"
-#include "cmStringCommand.h"
 
 cmConditionEvaluator::cmConditionEvaluator(cmMakefile& makefile):
   Makefile(makefile),
@@ -556,7 +555,7 @@ bool cmConditionEvaluator::HandleLevel2(cmArgumentList &newArgs,
         {
         def = this->GetVariableOrString(*arg);
         const char* rex = argP2->c_str();
-        cmStringCommand::ClearMatches(&this->Makefile);
+        this->Makefile.ClearMatches();
         cmsys::RegularExpression regEntry;
         if ( !regEntry.compile(rex) )
           {
@@ -568,7 +567,7 @@ bool cmConditionEvaluator::HandleLevel2(cmArgumentList &newArgs,
           }
         if (regEntry.find(def))
           {
-          cmStringCommand::StoreMatches(&this->Makefile, regEntry);
+          this->Makefile.StoreMatches(regEntry);
           *arg = cmExpandedCommandArgument("1", true);
           }
         else

Source/cmMakefile.cxx

@@ -4841,6 +4841,64 @@ std::vector<cmSourceFile*> cmMakefile::GetQtUiFilesWithOptions() const
   return this->QtUiFilesWithOptions;
 }
 
+static std::string const matchVariables[] = {
+  "CMAKE_MATCH_0",
+  "CMAKE_MATCH_1",
+  "CMAKE_MATCH_2",
+  "CMAKE_MATCH_3",
+  "CMAKE_MATCH_4",
+  "CMAKE_MATCH_5",
+  "CMAKE_MATCH_6",
+  "CMAKE_MATCH_7",
+  "CMAKE_MATCH_8",
+  "CMAKE_MATCH_9"
+};
+
+static std::string const nMatchesVariable = "CMAKE_MATCH_COUNT";
+
+//----------------------------------------------------------------------------
+void cmMakefile::ClearMatches()
+{
+  const char* nMatchesStr = this->GetDefinition(nMatchesVariable);
+  if (!nMatchesStr)
+    {
+    return;
+    }
+  int nMatches = atoi(nMatchesStr);
+  for (int i=0; i<=nMatches; i++)
+    {
+    std::string const& var = matchVariables[i];
+    std::string const& s = this->GetSafeDefinition(var);
+    if(!s.empty())
+      {
+      this->AddDefinition(var, "");
+      this->MarkVariableAsUsed(var);
+      }
+    }
+  this->AddDefinition(nMatchesVariable, "0");
+  this->MarkVariableAsUsed(nMatchesVariable);
+}
+
+//----------------------------------------------------------------------------
+void cmMakefile::StoreMatches(cmsys::RegularExpression& re)
+{
+  char highest = 0;
+  for (int i=0; i<10; i++)
+    {
+    std::string const& m = re.match(i);
+    if(!m.empty())
+      {
+      std::string const& var = matchVariables[i];
+      this->AddDefinition(var, m.c_str());
+      this->MarkVariableAsUsed(var);
+      highest = static_cast<char>('0' + i);
+      }
+    }
+  char nMatches[] = {highest, '\0'};
+  this->AddDefinition(nMatchesVariable, nMatches);
+  this->MarkVariableAsUsed(nMatchesVariable);
+}
+
 //----------------------------------------------------------------------------
 cmPolicies::PolicyStatus
 cmMakefile::GetPolicyStatus(cmPolicies::PolicyID id) const

Source/cmMakefile.h

@@ -976,6 +976,9 @@ public:
   void PopLoopBlock();
   bool IsLoopBlock() const;
 
+  void ClearMatches();
+  void StoreMatches(cmsys::RegularExpression& re);
+
 protected:
   // add link libraries and directories to the target
   void AddGlobalLinkInformation(const std::string& name, cmTarget& target);

Source/cmStringCommand.cxx

@@ -310,7 +310,7 @@ bool cmStringCommand::RegexMatch(std::vector<std::string> const& args)
     input += args[i];
     }
 
-  this->ClearMatches(this->Makefile);
+  this->Makefile->ClearMatches();
   // Compile the regular expression.
   cmsys::RegularExpression re;
   if(!re.compile(regex.c_str()))
@@ -325,7 +325,7 @@ bool cmStringCommand::RegexMatch(std::vector<std::string> const& args)
   std::string output;
   if(re.find(input.c_str()))
     {
-    this->StoreMatches(this->Makefile, re);
+    this->Makefile->StoreMatches(re);
     std::string::size_type l = re.start();
     std::string::size_type r = re.end();
     if(r-l == 0)
@@ -359,7 +359,7 @@ bool cmStringCommand::RegexMatchAll(std::vector<std::string> const& args)
     input += args[i];
     }
 
-  this->ClearMatches(this->Makefile);
+  this->Makefile->ClearMatches();
   // Compile the regular expression.
   cmsys::RegularExpression re;
   if(!re.compile(regex.c_str()))
@@ -376,7 +376,7 @@ bool cmStringCommand::RegexMatchAll(std::vector<std::string> const& args)
   const char* p = input.c_str();
   while(re.find(p))
     {
-    this->StoreMatches(this->Makefile, re);
+    this->Makefile->StoreMatches(re);
     std::string::size_type l = re.start();
     std::string::size_type r = re.end();
     if(r-l == 0)
@@ -463,7 +463,7 @@ bool cmStringCommand::RegexReplace(std::vector<std::string> const& args)
     input += args[i];
     }
 
-  this->ClearMatches(this->Makefile);
+  this->Makefile->ClearMatches();
   // Compile the regular expression.
   cmsys::RegularExpression re;
   if(!re.compile(regex.c_str()))
@@ -480,7 +480,7 @@ bool cmStringCommand::RegexReplace(std::vector<std::string> const& args)
   std::string::size_type base = 0;
   while(re.find(input.c_str()+base))
     {
-    this->StoreMatches(this->Makefile, re);
+    this->Makefile->StoreMatches(re);
     std::string::size_type l2 = re.start();
     std::string::size_type r = re.end();
 
@@ -540,38 +540,6 @@ bool cmStringCommand::RegexReplace(std::vector<std::string> const& args)
   return true;
 }
 
-//----------------------------------------------------------------------------
-void cmStringCommand::ClearMatches(cmMakefile* mf)
-{
-  for (unsigned int i=0; i<10; i++)
-    {
-    char name[128];
-    sprintf(name, "CMAKE_MATCH_%d", i);
-    const char* s = mf->GetDefinition(name);
-    if(s && *s != 0)
-      {
-      mf->AddDefinition(name, "");
-      mf->MarkVariableAsUsed(name);
-      }
-    }
-}
-
-//----------------------------------------------------------------------------
-void cmStringCommand::StoreMatches(cmMakefile* mf,cmsys::RegularExpression& re)
-{
-  for (unsigned int i=0; i<10; i++)
-    {
-    std::string m = re.match(i);
-    if(m.size() > 0)
-      {
-      char name[128];
-      sprintf(name, "CMAKE_MATCH_%d", i);
-      mf->AddDefinition(name, re.match(i).c_str());
-      mf->MarkVariableAsUsed(name);
-      }
-    }
-}
-
 //----------------------------------------------------------------------------
 bool cmStringCommand::HandleFindCommand(std::vector<std::string> const&
                                            args)

Source/cmStringCommand.h

@@ -53,8 +53,6 @@ public:
   virtual std::string GetName() const { return "string";}
 
   cmTypeMacro(cmStringCommand, cmCommand);
-  static void ClearMatches(cmMakefile* mf);
-  static void StoreMatches(cmMakefile* mf, cmsys::RegularExpression& re);
 protected:
   bool HandleConfigureCommand(std::vector<std::string> const& args);
   bool HandleAsciiCommand(std::vector<std::string> const& args);