[Libguestfs] [libguestfs-common PATCH 3/3] add common ("standard") option -w / --wrap

[Laszlo Ersek]

Similarly to how users can can force ANSI colorization with "--colors"
even when stdout / stderr are redirected to a non-tty, allow them to force
wrapping with "--wrap".

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1820221
Signed-off-by: Laszlo Ersek <lersek at redhat.com>
---

Notes:
    - This patch will require documentation updates for the following
      guestfs-tools utilities (those that already document "--colours"):
    
        builder/virt-builder-repository.pod
        builder/virt-builder.pod
        customize/virt-customize.pod
        dib/virt-dib.pod
        get-kernel/virt-get-kernel.pod
        resize/virt-resize.pod
        sparsify/virt-sparsify.pod
        sysprep/virt-sysprep.pod
    
      Virt-v2v as well:
    
        docs/virt-v2v.pod
    
      This is evident e.g. from "test-virt-customize-docs.sh" failing in
      guestfs-tools, and "test-v2v-docs.sh" failing in virt-v2v.
    
      If this patch is accepted, I intend to post such guestfs-tools and
      virt-v2v patches that atomically bump the submodule reference and
      update the documentation.
    
    - Some utilities in libguestfs already use the short "-w" option
      (guestfish, guestmount, virt-rescue); however, those utilities do not
      document "--colours", so they already don't make a TTY-based
      distinction, and will not see the new short "-w" option.
    
    - Easily testable e.g. with virt-resize:
    
      $ guestfish -N fs:ext4 exit
      $ truncate -s 2G test1.resized.img
      $ virt-resize    --expand /dev/sda1 test1.img test1.resized.img
      $ virt-resize -w --expand /dev/sda1 test1.img test1.resized.img
      $ virt-resize    --expand /dev/sda1 test1.img test1.resized.img > log1
      $ virt-resize -w --expand /dev/sda1 test1.img test1.resized.img > log2
      $ cat log1
      $ cat log2

 mlstdutils/std_utils.mli | 6 ++++--
 mlstdutils/std_utils.ml  | 8 ++++++--
 mltools/tools_utils.ml   | 3 ++-
 mltools/test-getopt.sh   | 2 ++
 4 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/mlstdutils/std_utils.mli b/mlstdutils/std_utils.mli
index 534caa80d6a7..87e923e24d29 100644
--- a/mlstdutils/std_utils.mli
+++ b/mlstdutils/std_utils.mli
@@ -376,8 +376,10 @@ val set_trace : unit -> unit
 val trace : unit -> bool
 val set_verbose : unit -> unit
 val verbose : unit -> bool
-(** Stores the colours ([--colours]), quiet ([--quiet]), trace ([-x]) and
-    verbose ([-v]) flags in global variables. *)
+val set_wrap : unit -> unit
+val wrap : unit -> bool
+(** Stores the colours ([--colours]), quiet ([--quiet]), trace ([-x]), verbose
+    ([-v]) and wrap ([-w]) flags in global variables. *)
 
 val with_open_in : string -> (in_channel -> 'a) -> 'a
 (** [with_open_in filename f] calls function [f] with [filename]
diff --git a/mlstdutils/std_utils.ml b/mlstdutils/std_utils.ml
index 58ac058c1b3a..52f44760c490 100644
--- a/mlstdutils/std_utils.ml
+++ b/mlstdutils/std_utils.ml
@@ -580,8 +580,8 @@ let which executable =
 (* Program name. *)
 let prog = Filename.basename Sys.executable_name
 
-(* Stores the colours (--colours), quiet (--quiet), trace (-x) and
- * verbose (-v) flags in a global variable.
+(* Stores the colours (--colours), quiet (--quiet), trace (-x), verbose (-v)
+ * and wrap (-w) flags in a global variable.
  *)
 let colours = ref false
 let set_colours () = colours := true
@@ -599,6 +599,10 @@ let verbose = ref false
 let set_verbose () = verbose := true
 let verbose () = !verbose
 
+let wrap = ref false
+let set_wrap () = wrap := true
+let wrap () = !wrap
+
 let with_open_in filename f =
   let chan = open_in filename in
   protect ~f:(fun () -> f chan) ~finally:(fun () -> close_in chan)
diff --git a/mltools/tools_utils.ml b/mltools/tools_utils.ml
index 4c5188988e03..eb8da290eec6 100644
--- a/mltools/tools_utils.ml
+++ b/mltools/tools_utils.ml
@@ -126,7 +126,7 @@ let message fs =
 type wrap_break_t = WrapEOS | WrapSpace | WrapNL
 
 let rec wrap ?(chan = stdout) ?(indent = 0) str =
-  if istty chan then
+  if Std_utils.wrap () || istty chan then
     let len = String.length str in
     _wrap chan indent 0 0 len str
   else (
@@ -388,6 +388,7 @@ let create_standard_options argspec ?anon_fun ?(key_opts = false)
   add_argspec ([ S 'q'; L"quiet" ],   Getopt.Unit set_quiet,    s_"Don’t print progress messages");
   add_argspec ([ L"color"; L"colors";
                  L"colour"; L"colours" ], Getopt.Unit set_colours, s_"Use ANSI colour sequences even if not tty");
+  add_argspec ([ S 'w'; L"wrap" ],    Getopt.Unit set_wrap,     s_"Wrap log messages even if not tty");
 
   if key_opts then (
     let parse_key_selector arg =
diff --git a/mltools/test-getopt.sh b/mltools/test-getopt.sh
index d9919a9a915a..1d7bb7b1dc4f 100755
--- a/mltools/test-getopt.sh
+++ b/mltools/test-getopt.sh
@@ -68,6 +68,7 @@ $t --short-options | grep '^-is'
 $t --short-options | grep '^-t'
 $t --short-options | grep '^-V'
 $t --short-options | grep '^-v'
+$t --short-options | grep '^-w'
 $t --short-options | grep '^-x'
 
 # --long-options
@@ -89,6 +90,7 @@ $t --long-options | grep '^--ii'
 $t --long-options | grep '^--is'
 $t --long-options | grep '^--version'
 $t --long-options | grep '^--verbose'
+$t --long-options | grep '^--wrap'
 
 # -a/--add parameter.
 $t | grep '^adds = \[\]'
-- 
2.19.1.3.g30247aa5d201