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, 5 insertions, 9 deletions

diff --git a/Source/cmAddSubDirectoryCommand.cxx b/Source/cmAddSubDirectoryCommand.cxx
index 50c682f..17bdc4a 100644
--- a/Source/cmAddSubDirectoryCommand.cxx
+++ b/Source/cmAddSubDirectoryCommand.cxx
@@ -8,6 +8,7 @@
 #include "cmExecutionStatus.h"
 #include "cmMakefile.h"
 #include "cmRange.h"
+#include "cmStringAlgorithms.h"
 #include "cmSystemTools.h"
 
 bool cmAddSubDirectoryCommand(std::vector<std::string> const& args,
@@ -45,14 +46,11 @@ bool cmAddSubDirectoryCommand(std::vector<std::string> const& args,
   if (cmSystemTools::FileIsFullPath(srcArg)) {
     srcPath = srcArg;
   } else {
-    srcPath = mf.GetCurrentSourceDirectory();
-    srcPath += "/";
-    srcPath += srcArg;
+    srcPath = cmStrCat(mf.GetCurrentSourceDirectory(), '/', srcArg);
   }
   if (!cmSystemTools::FileIsDirectory(srcPath)) {
-    std::string error = "given source \"";
-    error += srcArg;
-    error += "\" which is not an existing directory.";
+    std::string error = cmStrCat("given source \"", srcArg,
+                                 "\" which is not an existing directory.");
     status.SetError(error);
     return false;
   }
@@ -95,9 +93,7 @@ bool cmAddSubDirectoryCommand(std::vector<std::string> const& args,
     if (cmSystemTools::FileIsFullPath(binArg)) {
       binPath = binArg;
     } else {
-      binPath = mf.GetCurrentBinaryDirectory();
-      binPath += "/";
-      binPath += binArg;
+      binPath = cmStrCat(mf.GetCurrentBinaryDirectory(), '/', binArg);
     }
   }
   binPath = cmSystemTools::CollapseFullPath(binPath);