Source sweep: Use cmStrCat for string concatenation

This patch is generated by a python script that uses regular expressions to
search for string concatenation patterns of the kind

```
std::string str = <ARG0>;
str += <ARG1>;
str += <ARG2>;
...
```

and replaces them with a single `cmStrCat` call

```
std::string str = cmStrCat(<ARG0>, <ARG1>, <ARG2>, ...);
```

If any `<ARGX>` is itself a concatenated string of the kind

```
a + b + c + ...;
```

then `<ARGX>` is split into multiple arguments for the `cmStrCat` call.

If there's a sequence of literals in the `<ARGX>`, then all literals in the
sequence are concatenated and merged into a single literal argument for
the `cmStrCat` call.

Single character strings are converted to single char arguments for
the `cmStrCat` call.

`std::to_string(...)` wrappings are removed from `cmStrCat` arguments,
because it supports numeric types as well as string types.

`arg.substr(x)` arguments to `cmStrCat` are replaced with
`cm::string_view(arg).substr(x)`

1 files changed, 8 insertions, 13 deletions

diff --git a/Source/cmFileCopier.cxx b/Source/cmFileCopier.cxx
index 2e54b88..3156c95 100644
--- a/Source/cmFileCopier.cxx
+++ b/Source/cmFileCopier.cxx
@@ -314,8 +314,8 @@ bool cmFileCopier::CheckValue(std::string const& arg)
       if (arg.empty() || cmSystemTools::FileIsFullPath(arg)) {
         this->Destination = arg;
       } else {
-        this->Destination = this->Makefile->GetCurrentBinaryDirectory();
-        this->Destination += "/" + arg;
+        this->Destination =
+          cmStrCat(this->Makefile->GetCurrentBinaryDirectory(), '/', arg);
       }
       this->Doing = DoingNone;
       break;
@@ -323,8 +323,8 @@ bool cmFileCopier::CheckValue(std::string const& arg)
       if (cmSystemTools::FileIsFullPath(arg)) {
         this->FilesFromDir = arg;
       } else {
-        this->FilesFromDir = this->Makefile->GetCurrentSourceDirectory();
-        this->FilesFromDir += "/" + arg;
+        this->FilesFromDir =
+          cmStrCat(this->Makefile->GetCurrentSourceDirectory(), '/', arg);
       }
       cmSystemTools::ConvertToUnixSlashes(this->FilesFromDir);
       this->Doing = DoingNone;
@@ -334,9 +334,8 @@ bool cmFileCopier::CheckValue(std::string const& arg)
       // leading slash and trailing end-of-string in the matched
       // string to make sure the pattern matches only whole file
       // names.
-      std::string regex = "/";
-      regex += cmsys::Glob::PatternToRegex(arg, false);
-      regex += "$";
+      std::string regex =
+        cmStrCat('/', cmsys::Glob::PatternToRegex(arg, false), '$');
       this->MatchRules.emplace_back(regex);
       this->CurrentMatchRule = &*(this->MatchRules.end() - 1);
       if (this->CurrentMatchRule->Regex.is_valid()) {
@@ -699,12 +698,8 @@ bool cmFileCopier::InstallDirectory(const std::string& source,
   for (unsigned long fileNum = 0; fileNum < numFiles; ++fileNum) {
     if (!(strcmp(dir.GetFile(fileNum), ".") == 0 ||
           strcmp(dir.GetFile(fileNum), "..") == 0)) {
-      std::string fromPath = source;
-      fromPath += "/";
-      fromPath += dir.GetFile(fileNum);
-      std::string toPath = destination;
-      toPath += "/";
-      toPath += dir.GetFile(fileNum);
+      std::string fromPath = cmStrCat(source, '/', dir.GetFile(fileNum));
+      std::string toPath = cmStrCat(destination, '/', dir.GetFile(fileNum));
       if (!this->Install(fromPath, toPath)) {
         return false;
       }