cmGeneratorExpression: Re-write for multi-stage evaluation

The expressions may be parsed and then cached and evaluated multiple
times.  They are evaluated lazily so that literals such as ',' can be
treated as universal parameter separators, and can be processed from
results without appearing literally, and without interfering with the
parsing/evaluation of the entire expression.

1 files changed, 53 insertions, 187 deletions

diff --git a/Source/cmGeneratorExpression.cxx b/Source/cmGeneratorExpression.cxx
index 92bbf1d..198b43a 100644
--- a/Source/cmGeneratorExpression.cxx
+++ b/Source/cmGeneratorExpression.cxx
@@ -16,18 +16,17 @@
 
 #include <cmsys/String.h>
 
+#include "cmGeneratorExpressionEvaluator.h"
+#include "cmGeneratorExpressionLexer.h"
+#include "cmGeneratorExpressionParser.h"
+
 //----------------------------------------------------------------------------
 cmGeneratorExpression::cmGeneratorExpression(
   cmMakefile* mf, const char* config,
   cmListFileBacktrace const& backtrace, bool quiet):
-  Makefile(mf), Config(config), Backtrace(backtrace), Quiet(quiet)
+  Makefile(mf), Config(config), Backtrace(backtrace), Quiet(quiet),
+  NeedsParsing(true)
 {
-  this->TargetInfo.compile("^\\$<TARGET"
-                           "(|_SONAME|_LINKER)"  // File with what purpose?
-                           "_FILE(|_NAME|_DIR):" // Filename component.
-                           "([A-Za-z0-9_.-]+)"   // Target name.
-                           ">$");
-  this->TestConfig.compile("^\\$<CONFIG:([A-Za-z0-9_]*)>$");
 }
 
 //----------------------------------------------------------------------------
@@ -39,210 +38,77 @@ const char* cmGeneratorExpression::Process(std::string const& input)
 //----------------------------------------------------------------------------
 const char* cmGeneratorExpression::Process(const char* input)
 {
-  this->Data.clear();
-
-  // We construct and evaluate expressions directly in the output
-  // buffer.  Each expression is replaced by its own output value
-  // after evaluation.  A stack of barriers records the starting
-  // indices of open (pending) expressions.
-  for(const char* c = input; *c; ++c)
-    {
-    if(c[0] == '$' && c[1] == '<')
-      {
-      this->Barriers.push(this->Data.size());
-      this->Data.push_back('$');
-      this->Data.push_back('<');
-      c += 1;
-      }
-    else if(c[0] == '>' && !this->Barriers.empty())
-      {
-      this->Data.push_back('>');
-      if(!this->Evaluate()) { break; }
-      this->Barriers.pop();
-      }
-    else
-      {
-      this->Data.push_back(c[0]);
-      }
-    }
-
-  // Return a null-terminated output value.
-  this->Data.push_back('\0');
-  return &*this->Data.begin();
+  this->Parse(input);
+  return this->Evaluate(this->Makefile, this->Config, this->Quiet);
 }
 
 //----------------------------------------------------------------------------
-bool cmGeneratorExpression::Evaluate()
+void cmGeneratorExpression::Parse(const char* input)
 {
-  // The top-most barrier points at the beginning of the expression.
-  size_t barrier = this->Barriers.top();
+  this->Evaluators.clear();
 
-  // Construct a null-terminated representation of the expression.
-  this->Data.push_back('\0');
-  const char* expr = &*(this->Data.begin()+barrier);
+  this->Input = input;
+  cmGeneratorExpressionLexer l;
+  std::vector<cmGeneratorExpressionToken> tokens = l.Tokenize(this->Input);
+  this->NeedsParsing = l.GetSawGeneratorExpression();
 
-  // Evaluate the expression.
-  std::string result;
-  if(this->Evaluate(expr, result))
+  if (!this->NeedsParsing)
     {
-    // Success.  Replace the expression with its evaluation result.
-    this->Data.erase(this->Data.begin()+barrier, this->Data.end());
-    this->Data.insert(this->Data.end(), result.begin(), result.end());
-    return true;
+    return;
     }
-  else if(!this->Quiet)
-    {
-    // Failure.  Report the error message.
-    cmOStringStream e;
-    e << "Error evaluating generator expression:\n"
-      << "  " << expr << "\n"
-      << result;
-    this->Makefile->GetCMakeInstance()
-      ->IssueMessage(cmake::FATAL_ERROR, e.str().c_str(),
-                     this->Backtrace);
-    return false;
-    }
-  return true;
-}
 
-//----------------------------------------------------------------------------
-static bool cmGeneratorExpressionBool(const char* c, std::string& result,
-                                      const char* name,
-                                      const char* a, const char* b)
-{
-  result = a;
-  while((c[0] == '0' || c[0] == '1') && (c[1] == ',' || c[1] == '>'))
-    {
-    if(c[0] == b[0]) { result = b; }
-    c += 2;
-    }
-  if(c[0])
-    {
-    result = name;
-    result += " requires one or more comma-separated '0' or '1' values.";
-    return false;
-    }
-  return true;
+  cmGeneratorExpressionParser p(tokens);
+  p.Parse(this->Evaluators);
 }
 
 //----------------------------------------------------------------------------
-bool cmGeneratorExpression::Evaluate(const char* expr, std::string& result)
+const char *cmGeneratorExpression::Evaluate(
+  cmMakefile* mf, const char* config, bool quiet)
 {
-  if(this->TargetInfo.find(expr))
+  if (!this->NeedsParsing)
     {
-    if(!this->EvaluateTargetInfo(result))
-      {
-      return false;
-      }
+    return this->Input;
     }
-  else if(strcmp(expr, "$<CONFIGURATION>") == 0)
-    {
-    result = this->Config? this->Config : "";
-    }
-  else if(strncmp(expr, "$<0:",4) == 0)
-    {
-    result = "";
-    }
-  else if(strncmp(expr, "$<1:",4) == 0)
-    {
-    result = std::string(expr+4, strlen(expr)-5);
-    }
-  else if(strncmp(expr, "$<NOT:",6) == 0)
+
+  this->Output = "";
+
+  std::vector<cmGeneratorExpressionEvaluator*>::const_iterator it
+                                                  = this->Evaluators.begin();
+  const std::vector<cmGeneratorExpressionEvaluator*>::const_iterator end
+                                                  = this->Evaluators.end();
+
+  cmGeneratorExpressionContext context;
+  context.Makefile = mf;
+  context.Config = config;
+  context.Quiet = quiet;
+  context.HadError = false;
+  context.Backtrace = this->Backtrace;
+
+  for ( ; it != end; ++it)
     {
-    const char* c = expr+6;
-    if((c[0] != '0' && c[0] != '1') || c[1] != '>' || c[2])
+    this->Output += (*it)->Evaluate(&context);
+    if (context.HadError)
       {
-      result = "NOT requires exactly one '0' or '1' value.";
-      return false;
+      this->Output = "";
+      break;
       }
-    result = c[0] == '1'? "0" : "1";
-    }
-  else if(strncmp(expr, "$<AND:",6) == 0)
-    {
-    return cmGeneratorExpressionBool(expr+6, result, "AND", "1", "0");
-    }
-  else if(strncmp(expr, "$<OR:",5) == 0)
-    {
-    return cmGeneratorExpressionBool(expr+5, result, "OR", "0", "1");
-    }
-  else if(this->TestConfig.find(expr))
-    {
-    result = cmsysString_strcasecmp(this->TestConfig.match(1).c_str(),
-                                    this->Config? this->Config:"") == 0
-      ? "1":"0";
     }
-  else
-    {
-    result = "Expression syntax not recognized.";
-    return false;
-    }
-  return true;
+
+  this->Targets = context.Targets;
+  // TODO: Return a std::string from here instead?
+  return this->Output.c_str();
 }
 
 //----------------------------------------------------------------------------
-bool cmGeneratorExpression::EvaluateTargetInfo(std::string& result)
+cmGeneratorExpression::~cmGeneratorExpression()
 {
-  // Lookup the referenced target.
-  std::string name = this->TargetInfo.match(3);
-  cmTarget* target = this->Makefile->FindTargetToUse(name.c_str());
-  if(!target)
-    {
-    result = "No target \"" + name + "\"";
-    return false;
-    }
-  if(target->GetType() >= cmTarget::UTILITY &&
-     target->GetType() != cmTarget::UNKNOWN_LIBRARY)
-    {
-    result = "Target \"" + name + "\" is not an executable or library.";
-    return false;
-    }
-  this->Targets.insert(target);
+  std::vector<cmGeneratorExpressionEvaluator*>::const_iterator it
+                                                  = this->Evaluators.begin();
+  const std::vector<cmGeneratorExpressionEvaluator*>::const_iterator end
+                                                  = this->Evaluators.end();
 
-  // Lookup the target file with the given purpose.
-  std::string purpose = this->TargetInfo.match(1);
-  if(purpose == "")
-    {
-    // The target implementation file (.so.1.2, .dll, .exe, .a).
-    result = target->GetFullPath(this->Config, false, true);
-    }
-  else if(purpose == "_LINKER")
-    {
-    // The file used to link to the target (.so, .lib, .a).
-    if(!target->IsLinkable())
-      {
-      result = ("TARGET_LINKER_FILE is allowed only for libraries and "
-                "executables with ENABLE_EXPORTS.");
-      return false;
-      }
-    result = target->GetFullPath(this->Config, target->HasImportLibrary());
-    }
-  else if(purpose == "_SONAME")
-    {
-    // The target soname file (.so.1).
-    if(target->IsDLLPlatform())
-      {
-      result = "TARGET_SONAME_FILE is not allowed for DLL target platforms.";
-      return false;
-      }
-    if(target->GetType() != cmTarget::SHARED_LIBRARY)
-      {
-      result = "TARGET_SONAME_FILE is allowed only for SHARED libraries.";
-      return false;
-      }
-    result = target->GetDirectory(this->Config);
-    result += "/";
-    result += target->GetSOName(this->Config);
-    }
-
-  // Extract the requested portion of the full path.
-  std::string part = this->TargetInfo.match(2);
-  if(part == "_NAME")
-    {
-    result = cmSystemTools::GetFilenameName(result);
-    }
-  else if(part == "_DIR")
+  for ( ; it != end; ++it)
     {
-    result = cmSystemTools::GetFilenamePath(result);
+    delete *it;
     }
-  return true;
 }