file: add `COPY_FILE` subcommand

The `file(COPY)` subcommand is overloaded and busy for such a simple
operation. Instead, make a simpler subcommand with error handling
support.

1 files changed, 92 insertions, 0 deletions

diff --git a/Source/cmFileCommand.cxx b/Source/cmFileCommand.cxx
index 065b845..1c73d0d 100644
--- a/Source/cmFileCommand.cxx
+++ b/Source/cmFileCommand.cxx
@@ -1379,6 +1379,97 @@ bool HandleRename(std::vector<std::string> const& args,
   return false;
 }
 
+bool HandleCopyFile(std::vector<std::string> const& args,
+                    cmExecutionStatus& status)
+{
+  if (args.size() < 3) {
+    status.SetError("COPY_FILE must be called with at least two additional "
+                    "arguments");
+    return false;
+  }
+
+  // Compute full path for old and new names.
+  std::string oldname = args[1];
+  if (!cmsys::SystemTools::FileIsFullPath(oldname)) {
+    oldname =
+      cmStrCat(status.GetMakefile().GetCurrentSourceDirectory(), '/', args[1]);
+  }
+  std::string newname = args[2];
+  if (!cmsys::SystemTools::FileIsFullPath(newname)) {
+    newname =
+      cmStrCat(status.GetMakefile().GetCurrentSourceDirectory(), '/', args[2]);
+  }
+
+  struct Arguments
+  {
+    bool OnlyIfDifferent = false;
+    std::string Result;
+  };
+
+  static auto const parser =
+    cmArgumentParser<Arguments>{}
+      .Bind("ONLY_IF_DIFFERENT"_s, &Arguments::OnlyIfDifferent)
+      .Bind("RESULT"_s, &Arguments::Result);
+
+  std::vector<std::string> unconsumedArgs;
+  Arguments const arguments =
+    parser.Parse(cmMakeRange(args).advance(3), &unconsumedArgs);
+  if (!unconsumedArgs.empty()) {
+    status.SetError("COPY_FILE unknown argument:\n  " +
+                    unconsumedArgs.front());
+    return false;
+  }
+
+  bool result = true;
+  if (cmsys::SystemTools::FileIsDirectory(oldname)) {
+    if (!arguments.Result.empty()) {
+      status.GetMakefile().AddDefinition(arguments.Result,
+                                         "cannot copy a directory");
+    } else {
+      status.SetError(
+        cmStrCat("COPY_FILE cannot copy a directory\n  ", oldname));
+      result = false;
+    }
+    return result;
+  }
+  if (cmsys::SystemTools::FileIsDirectory(newname)) {
+    if (!arguments.Result.empty()) {
+      status.GetMakefile().AddDefinition(arguments.Result,
+                                         "cannot copy to a directory");
+    } else {
+      status.SetError(
+        cmStrCat("COPY_FILE cannot copy to a directory\n  ", newname));
+      result = false;
+    }
+    return result;
+  }
+
+  cmSystemTools::CopyWhen when;
+  if (arguments.OnlyIfDifferent) {
+    when = cmSystemTools::CopyWhen::OnlyIfDifferent;
+  } else {
+    when = cmSystemTools::CopyWhen::Always;
+  }
+
+  std::string err;
+  if (cmSystemTools::CopySingleFile(oldname, newname, when, &err) ==
+      cmSystemTools::CopyResult::Success) {
+    if (!arguments.Result.empty()) {
+      status.GetMakefile().AddDefinition(arguments.Result, "0");
+    }
+  } else {
+    if (!arguments.Result.empty()) {
+      status.GetMakefile().AddDefinition(arguments.Result, err);
+    } else {
+      status.SetError(cmStrCat("COPY_FILE failed to copy\n  ", oldname,
+                               "\nto\n  ", newname, "\nbecause: ", err, "\n"));
+      result = false;
+    }
+  }
+
+  return result;
+}
+
 bool HandleRemoveImpl(std::vector<std::string> const& args, bool recurse,
                       cmExecutionStatus& status)
 {
@@ -3609,6 +3700,7 @@ bool cmFileCommand(std::vector<std::string> const& args,
     { "GLOB_RECURSE"_s, HandleGlobRecurseCommand },
     { "MAKE_DIRECTORY"_s, HandleMakeDirectoryCommand },
     { "RENAME"_s, HandleRename },
+    { "COPY_FILE"_s, HandleCopyFile },
     { "REMOVE"_s, HandleRemove },
     { "REMOVE_RECURSE"_s, HandleRemoveRecurse },
     { "COPY"_s, HandleCopyCommand },