Use the empty() method to check for emptyness.

Apply fix-its from clang-tidy's readability-container-size-empty
checker.

Source/CTest/cmCTestBuildHandler.cxx

@@ -790,7 +790,7 @@ int cmCTestBuildHandler::RunMakeCommand(const char* command, int* retVal,
   // First generate the command and arguments
   std::vector<std::string> args = cmSystemTools::ParseArguments(command);
 
-  if (args.size() < 1) {
+  if (args.empty()) {
     return false;
   }
 

Source/CTest/cmCTestCurl.cxx

@@ -88,10 +88,10 @@ bool cmCTestCurl::InitCurl()
   if (this->VerifyHostOff) {
     curl_easy_setopt(this->Curl, CURLOPT_SSL_VERIFYHOST, 0);
   }
-  if (this->HTTPProxy.size()) {
+  if (!this->HTTPProxy.empty()) {
     curl_easy_setopt(this->Curl, CURLOPT_PROXY, this->HTTPProxy.c_str());
     curl_easy_setopt(this->Curl, CURLOPT_PROXYTYPE, this->HTTPProxyType);
-    if (this->HTTPProxyAuth.size() > 0) {
+    if (!this->HTTPProxyAuth.empty()) {
       curl_easy_setopt(this->Curl, CURLOPT_PROXYUSERPWD,
                        this->HTTPProxyAuth.c_str());
     }
@@ -160,17 +160,17 @@ bool cmCTestCurl::UploadFile(std::string const& local_file,
   ::curl_easy_setopt(this->Curl, CURLOPT_HTTPHEADER, NULL);
   ::curl_slist_free_all(headers);
 
-  if (responseData.size() > 0) {
+  if (!responseData.empty()) {
     response = std::string(responseData.begin(), responseData.end());
     cmCTestLog(this->CTest, HANDLER_VERBOSE_OUTPUT, "Curl response: ["
                  << response << "]\n");
   }
   std::string curlDebug;
-  if (debugData.size() > 0) {
+  if (!debugData.empty()) {
     curlDebug = std::string(debugData.begin(), debugData.end());
     cmCTestLog(this->CTest, DEBUG, "Curl debug: [" << curlDebug << "]\n");
   }
-  if (response.size() == 0) {
+  if (response.empty()) {
     cmCTestLog(this->CTest, ERROR_MESSAGE, "No response from server.\n"
                  << curlDebug);
     return false;
@@ -205,11 +205,11 @@ bool cmCTestCurl::HttpRequest(std::string const& url,
 
   CURLcode res = ::curl_easy_perform(this->Curl);
 
-  if (responseData.size() > 0) {
+  if (!responseData.empty()) {
     response = std::string(responseData.begin(), responseData.end());
     cmCTestLog(this->CTest, DEBUG, "Curl response: [" << response << "]\n");
   }
-  if (debugData.size() > 0) {
+  if (!debugData.empty()) {
     std::string curlDebug = std::string(debugData.begin(), debugData.end());
     cmCTestLog(this->CTest, DEBUG, "Curl debug: [" << curlDebug << "]\n");
   }

Source/CTest/cmCTestMemCheckHandler.cxx

@@ -499,11 +499,12 @@ bool cmCTestMemCheckHandler::InitializeMemoryChecking()
 
   // Setup the options
   std::string memoryTesterOptions;
-  if (this->CTest->GetCTestConfiguration("MemoryCheckCommandOptions").size()) {
+  if (!this->CTest->GetCTestConfiguration("MemoryCheckCommandOptions")
+         .empty()) {
     memoryTesterOptions =
       this->CTest->GetCTestConfiguration("MemoryCheckCommandOptions");
-  } else if (this->CTest->GetCTestConfiguration("ValgrindCommandOptions")
+  } else if (!this->CTest->GetCTestConfiguration("ValgrindCommandOptions")
-               .size()) {
+                .empty()) {
     memoryTesterOptions =
       this->CTest->GetCTestConfiguration("ValgrindCommandOptions");
   }
@@ -522,8 +523,8 @@ bool cmCTestMemCheckHandler::InitializeMemoryChecking()
         this->MemoryTesterOptions.push_back("--show-reachable=yes");
         this->MemoryTesterOptions.push_back("--num-callers=50");
       }
-      if (this->CTest->GetCTestConfiguration("MemoryCheckSuppressionFile")
+      if (!this->CTest->GetCTestConfiguration("MemoryCheckSuppressionFile")
-            .size()) {
+             .empty()) {
         if (!cmSystemTools::FileExists(
               this->CTest->GetCTestConfiguration("MemoryCheckSuppressionFile")
                 .c_str())) {

Source/CTest/cmCTestReadCustomFilesCommand.cxx

@@ -16,7 +16,7 @@
 bool cmCTestReadCustomFilesCommand::InitialPass(
   std::vector<std::string> const& args, cmExecutionStatus&)
 {
-  if (args.size() < 1) {
+  if (args.empty()) {
     this->SetError("called with incorrect number of arguments");
     return false;
   }

Source/CTest/cmCTestRunScriptCommand.cxx

@@ -16,7 +16,7 @@
 bool cmCTestRunScriptCommand::InitialPass(std::vector<std::string> const& args,
                                           cmExecutionStatus&)
 {
-  if (args.size() < 1) {
+  if (args.empty()) {
     this->CTestScriptHandler->RunCurrentScript();
     return true;
   }

Source/CTest/cmCTestRunTest.cxx

@@ -207,7 +207,8 @@ bool cmCTestRunTest::EndTest(size_t completed, size_t total, bool started)
   }
   if (res == cmsysProcess_State_Exited) {
     bool success = !forceFail &&
-      (retVal == 0 || this->TestProperties->RequiredRegularExpressions.size());
+      (retVal == 0 ||
+       !this->TestProperties->RequiredRegularExpressions.empty());
     if (this->TestProperties->SkipReturnCode >= 0 &&
         this->TestProperties->SkipReturnCode == retVal) {
       this->TestResult.Status = cmCTestTestHandler::NOT_RUN;
@@ -537,7 +538,7 @@ void cmCTestRunTest::ComputeArguments()
                << " command: " << testCommand << std::endl);
 
   // Print any test-specific env vars in verbose mode
-  if (this->TestProperties->Environment.size()) {
+  if (!this->TestProperties->Environment.empty()) {
     cmCTestLog(this->CTest, HANDLER_VERBOSE_OUTPUT, this->Index
                  << ": "
                  << "Environment variables: " << std::endl);

Source/CTest/cmCTestSleepCommand.cxx

@@ -17,7 +17,7 @@
 bool cmCTestSleepCommand::InitialPass(std::vector<std::string> const& args,
                                       cmExecutionStatus&)
 {
-  if (args.size() < 1) {
+  if (args.empty()) {
     this->SetError("called with incorrect number of arguments");
     return false;
   }

Source/CTest/cmCTestStartCommand.cxx

@@ -25,7 +25,7 @@ cmCTestStartCommand::cmCTestStartCommand()
 bool cmCTestStartCommand::InitialPass(std::vector<std::string> const& args,
                                       cmExecutionStatus&)
 {
-  if (args.size() < 1) {
+  if (args.empty()) {
     this->SetError("called with incorrect number of arguments");
     return false;
   }

Source/CTest/cmCTestSubmitHandler.cxx

@@ -999,12 +999,12 @@ void cmCTestSubmitHandler::ConstructCDashURL(std::string& dropMethod,
   dropMethod = this->CTest->GetCTestConfiguration("DropMethod");
   url = dropMethod;
   url += "://";
-  if (this->CTest->GetCTestConfiguration("DropSiteUser").size() > 0) {
+  if (!this->CTest->GetCTestConfiguration("DropSiteUser").empty()) {
     url += this->CTest->GetCTestConfiguration("DropSiteUser");
     cmCTestOptionalLog(
       this->CTest, HANDLER_OUTPUT,
       this->CTest->GetCTestConfiguration("DropSiteUser").c_str(), this->Quiet);
-    if (this->CTest->GetCTestConfiguration("DropSitePassword").size() > 0) {
+    if (!this->CTest->GetCTestConfiguration("DropSitePassword").empty()) {
       url += ":" + this->CTest->GetCTestConfiguration("DropSitePassword");
       cmCTestOptionalLog(this->CTest, HANDLER_OUTPUT, ":******", this->Quiet);
     }

Source/CTest/cmCTestTestHandler.cxx

@@ -69,7 +69,7 @@ public:
 bool cmCTestSubdirCommand::InitialPass(std::vector<std::string> const& args,
                                        cmExecutionStatus&)
 {
-  if (args.size() < 1) {
+  if (args.empty()) {
     this->SetError("called with incorrect number of arguments");
     return false;
   }
@@ -150,7 +150,7 @@ public:
 bool cmCTestAddSubdirectoryCommand::InitialPass(
   std::vector<std::string> const& args, cmExecutionStatus&)
 {
-  if (args.size() < 1) {
+  if (args.empty()) {
     this->SetError("called with incorrect number of arguments");
     return false;
   }
@@ -1125,7 +1125,7 @@ void cmCTestTestHandler::AttachFiles(cmXMLWriter& xml,
                                      cmCTestTestResult* result)
 {
   if (result->Status != cmCTestTestHandler::COMPLETED &&
-      result->Properties->AttachOnFail.size()) {
+      !result->Properties->AttachOnFail.empty()) {
     result->Properties->AttachedFiles.insert(
       result->Properties->AttachedFiles.end(),
       result->Properties->AttachOnFail.begin(),

Source/CTest/cmParseJacocoCoverage.cxx

@@ -111,7 +111,7 @@ protected:
     gl.RecurseThroughSymlinksOn();
     gl.FindFiles(packageGlob);
     std::vector<std::string> const& files = gl.GetFiles();
-    if (files.size() == 0) {
+    if (files.empty()) {
       return false;
     }
 

Source/cmArchiveWrite.cxx

@@ -255,7 +255,7 @@ bool cmArchiveWrite::AddFile(const char* file, size_t skip, const char* prefix)
     archive_entry_set_gid(e, this->Gid.Get());
   }
 
-  if (this->Uname.size() && this->Gname.size()) {
+  if (!this->Uname.empty() && !this->Gname.empty()) {
     archive_entry_set_uname(e, this->Uname.c_str());
     archive_entry_set_gname(e, this->Gname.c_str());
   }

Source/cmCTest.cxx

@@ -1020,7 +1020,7 @@ int cmCTest::RunMakeCommand(const char* command, std::string& output,
   // First generate the command and arguments
   std::vector<std::string> args = cmSystemTools::ParseArguments(command);
 
-  if (args.size() < 1) {
+  if (args.empty()) {
     return false;
   }
 
@@ -2525,7 +2525,7 @@ bool cmCTest::RunCommand(const char* command, std::string* stdOut,
 {
   std::vector<std::string> args = cmSystemTools::ParseArguments(command);
 
-  if (args.size() < 1) {
+  if (args.empty()) {
     return false;
   }
 

Source/cmExtraCodeBlocksGenerator.cxx

@@ -248,7 +248,7 @@ void cmExtraCodeBlocksGenerator::CreateNewProjectFile(
       // We don't want paths with CMakeFiles in them
       // or do we?
       // In speedcrunch those where purely internal
-      if (splitted.size() >= 1 &&
+      if (!splitted.empty() &&
           relative.find("CMakeFiles") == std::string::npos) {
         tree.InsertPath(splitted, 1, fileName);
       }
@@ -729,7 +729,7 @@ std::string cmExtraCodeBlocksGenerator::BuildMakeCommand(
   const std::string& makeFlags)
 {
   std::string command = make;
-  if (makeFlags.size() > 0) {
+  if (!makeFlags.empty()) {
     command += " ";
     command += makeFlags;
   }

Source/cmMakefileTargetGenerator.cxx

@@ -848,7 +848,7 @@ bool cmMakefileTargetGenerator::WriteMakeRule(
   const std::vector<std::string>& commands, bool in_help)
 {
   bool symbolic = false;
-  if (outputs.size() == 0) {
+  if (outputs.empty()) {
     return symbolic;
   }
 

Source/cmSystemTools.cxx

@@ -702,7 +702,7 @@ bool cmSystemTools::RunSingleCommand(const char* command,
 
   std::vector<std::string> args = cmSystemTools::ParseArguments(command);
 
-  if (args.size() < 1) {
+  if (args.empty()) {
     return false;
   }
   return cmSystemTools::RunSingleCommand(args, captureStdOut, captureStdErr,