libtextstyle-optional: New module.

* lib/textstyle.in.h: New file, based on libtextstyle's textstyle.h.
* m4/libtextstyle-optional.m4: New file, based on m4/libtextstyle.m4.
* modules/libtextstyle-optional: New file.

1 files changed, 377 insertions, 0 deletions

diff --git a/lib/textstyle.in.h b/lib/textstyle.in.h
new file mode 100644
index 0000000000..65fa6707a2
--- /dev/null
+++ b/lib/textstyle.in.h
@@ -0,0 +1,377 @@
+/* Dummy replacement for part of the public API of the libtextstyle library.
+   Copyright (C) 2006-2007, 2019 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2019.  */
+
+/* This file is used as replacement when libtextstyle with its include file
+   <textstyle.h> is not found.
+   It supports the essential API and implements it in a way that does not
+   provide text styling.  That is, it produces plain text output via <stdio.h>
+   FILE objects.
+   Thus, it allows a package to be build with or without a dependency to
+   libtextstyle, with very few occurrences of '#if HAVE_LIBTEXTSTYLE'.
+
+   Restriction:
+   It assumes that freopen() is not being called on stdout and stderr.  */
+
+#ifndef _TEXTSTYLE_H
+#define _TEXTSTYLE_H
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#if HAVE_TCDRAIN
+# include <termios.h>
+#endif
+
+/* ----------------------------- From ostream.h ----------------------------- */
+
+/* Describes the scope of a flush operation.  */
+typedef enum
+{
+  /* Flushes buffers in this ostream_t.
+     Use this value if you want to write to the underlying ostream_t.  */
+  FLUSH_THIS_STREAM = 0,
+  /* Flushes all buffers in the current process.
+     Use this value if you want to write to the same target through a
+     different file descriptor or a FILE stream.  */
+  FLUSH_THIS_PROCESS = 1,
+  /* Flushes buffers in the current process and attempts to flush the buffers
+     in the kernel.
+     Use this value so that some other process (or the kernel itself)
+     may write to the same target.  */
+  FLUSH_ALL = 2
+} ostream_flush_scope_t;
+
+
+/* An output stream is an object to which one can feed a sequence of bytes.  */
+
+typedef FILE * ostream_t;
+
+static inline void
+ostream_write_mem (ostream_t stream, const void *data, size_t len)
+{
+  if (len > 0)
+    fwrite (data, 1, len, stream);
+}
+
+static inline void
+ostream_flush (ostream_t stream, ostream_flush_scope_t scope)
+{
+  fflush (stream);
+  if (scope == FLUSH_ALL)
+    {
+      int fd = fileno (stream);
+      if (fd >= 0)
+        {
+          /* For streams connected to a disk file:  */
+          fsync (fd);
+          #if HAVE_TCDRAIN
+          /* For streams connected to a terminal:  */
+          {
+            int retval;
+
+            do
+              retval = tcdrain (fd);
+            while (retval < 0 && errno == EINTR);
+          }
+          #endif
+        }
+    }
+}
+
+static inline void
+ostream_free (ostream_t stream)
+{
+  if (stream == stdin || stream == stderr)
+    fflush (stream);
+  else
+    fclose (stream);
+}
+
+static inline void
+ostream_write_str (ostream_t stream, const char *string)
+{
+  ostream_write_mem (stream, string, strlen (string));
+}
+
+/* ------------------------- From styled-ostream.h ------------------------- */
+
+typedef ostream_t styled_ostream_t;
+
+#define styled_ostream_write_mem ostream_write_mem
+#define styled_ostream_flush ostream_flush
+#define styled_ostream_free ostream_free
+
+static inline void
+styled_ostream_begin_use_class (styled_ostream_t stream _GL_UNUSED,
+                                const char *classname _GL_UNUSED)
+{
+}
+
+static inline void
+styled_ostream_end_use_class (styled_ostream_t stream _GL_UNUSED,
+                              const char *classname _GL_UNUSED)
+{
+}
+
+static inline void
+styled_ostream_flush_to_current_style (styled_ostream_t stream _GL_UNUSED)
+{
+}
+
+/* -------------------------- From file-ostream.h -------------------------- */
+
+typedef ostream_t file_ostream_t;
+
+#define file_ostream_write_mem ostream_write_mem
+#define file_ostream_flush ostream_flush
+#define file_ostream_free ostream_free
+
+static inline file_ostream_t
+file_ostream_create (FILE *fp)
+{
+  return fp;
+}
+
+/* --------------------------- From fd-ostream.h --------------------------- */
+
+typedef ostream_t fd_ostream_t;
+
+#define fd_ostream_write_mem ostream_write_mem
+#define fd_ostream_flush ostream_flush
+#define fd_ostream_free ostream_free
+
+static inline fd_ostream_t
+fd_ostream_create (int fd, const char *filename _GL_UNUSED,
+                   bool buffered _GL_UNUSED)
+{
+  if (fd == 1)
+    return stdout;
+  else if (fd == 2)
+    return stderr;
+  else
+    return fdopen (fd, "w");
+}
+
+/* -------------------------- From term-ostream.h -------------------------- */
+
+typedef int term_color_t;
+enum
+{
+  COLOR_DEFAULT = -1  /* unknown */
+};
+
+typedef enum
+{
+  WEIGHT_NORMAL = 0,
+  WEIGHT_BOLD,
+  WEIGHT_DEFAULT = WEIGHT_NORMAL
+} term_weight_t;
+
+typedef enum
+{
+  POSTURE_NORMAL = 0,
+  POSTURE_ITALIC, /* same as oblique */
+  POSTURE_DEFAULT = POSTURE_NORMAL
+} term_posture_t;
+
+typedef enum
+{
+  UNDERLINE_OFF = 0,
+  UNDERLINE_ON,
+  UNDERLINE_DEFAULT = UNDERLINE_OFF
+} term_underline_t;
+
+typedef ostream_t term_ostream_t;
+
+#define term_ostream_write_mem ostream_write_mem
+#define term_ostream_flush ostream_flush
+#define term_ostream_free ostream_free
+
+static inline term_color_t
+term_ostream_get_color (term_ostream_t stream _GL_UNUSED)
+{
+  return COLOR_DEFAULT;
+}
+
+static inline void
+term_ostream_set_color (term_ostream_t stream _GL_UNUSED,
+                        term_color_t color _GL_UNUSED)
+{
+}
+
+static inline term_color_t
+term_ostream_get_bgcolor (term_ostream_t stream _GL_UNUSED)
+{
+  return COLOR_DEFAULT;
+}
+
+static inline void
+term_ostream_set_bgcolor (term_ostream_t stream _GL_UNUSED,
+                          term_color_t color _GL_UNUSED)
+{
+}
+
+static inline term_weight_t
+term_ostream_get_weight (term_ostream_t stream _GL_UNUSED)
+{
+  return WEIGHT_DEFAULT;
+}
+
+static inline void
+term_ostream_set_weight (term_ostream_t stream _GL_UNUSED,
+                         term_weight_t weight _GL_UNUSED)
+{
+}
+
+static inline term_posture_t
+term_ostream_get_posture (term_ostream_t stream _GL_UNUSED)
+{
+  return POSTURE_DEFAULT;
+}
+
+static inline void
+term_ostream_set_posture (term_ostream_t stream _GL_UNUSED,
+                          term_posture_t posture _GL_UNUSED)
+{
+}
+
+static inline term_underline_t
+term_ostream_get_underline (term_ostream_t stream _GL_UNUSED)
+{
+  return UNDERLINE_DEFAULT;
+}
+
+static inline void
+term_ostream_set_underline (term_ostream_t stream _GL_UNUSED,
+                            term_underline_t underline _GL_UNUSED)
+{
+}
+
+static inline void
+term_ostream_flush_to_current_style (term_ostream_t stream)
+{
+  fflush (stream);
+}
+
+typedef enum
+{
+  TTYCTL_AUTO = 0,  /* Automatic best-possible choice.  */
+  TTYCTL_NONE,      /* No control.
+                       Result: Garbled output can occur, and the terminal can
+                       be left in any state when the program is interrupted.  */
+  TTYCTL_PARTIAL,   /* Signal handling.
+                       Result: Garbled output can occur, but the terminal will
+                       be left in the default state when the program is
+                       interrupted.  */
+  TTYCTL_FULL       /* Signal handling and disabling echo and flush-upon-signal.
+                       Result: No garbled output, and the the terminal will
+                       be left in the default state when the program is
+                       interrupted.  */
+} ttyctl_t;
+
+static inline term_ostream_t
+term_ostream_create (int fd, const char *filename,
+                     ttyctl_t tty_control _GL_UNUSED)
+{
+  return fd_ostream_create (fd, filename, true);
+}
+
+/* ----------------------- From term-styled-ostream.h ----------------------- */
+
+typedef styled_ostream_t term_styled_ostream_t;
+
+#define term_styled_ostream_write_mem ostream_write_mem
+#define term_styled_ostream_flush ostream_flush
+#define term_styled_ostream_free ostream_free
+#define term_styled_ostream_begin_use_class styled_ostream_begin_use_class
+#define term_styled_ostream_end_use_class styled_ostream_end_use_class
+#define term_styled_ostream_flush_to_current_style styled_ostream_flush_to_current_style
+
+static inline term_styled_ostream_t
+term_styled_ostream_create (int fd, const char *filename,
+                            ttyctl_t tty_control _GL_UNUSED,
+                            const char *css_filename _GL_UNUSED)
+{
+  return fd_ostream_create (fd, filename, true);
+}
+
+/* ----------------------- From html-styled-ostream.h ----------------------- */
+
+typedef styled_ostream_t html_styled_ostream_t;
+
+static inline html_styled_ostream_t
+html_styled_ostream_create (ostream_t destination, const char *css_filename)
+{
+  abort ();
+  return NULL;
+}
+
+/* ------------------------------ From color.h ------------------------------ */
+
+#define color_test_mode false
+
+enum color_option { color_no, color_tty, color_yes, color_html };
+#define color_mode color_no
+
+#define style_file_name NULL
+
+static inline bool
+handle_color_option (const char *option _GL_UNUSED)
+{
+  return false;
+}
+
+static inline void
+handle_style_option (const char *option _GL_UNUSED)
+{
+}
+
+static inline void
+print_color_test (void)
+{
+  abort ();
+}
+
+static inline void
+style_file_prepare (const char *style_file_envvar _GL_UNUSED,
+                    const char *stylesdir_envvar _GL_UNUSED,
+                    const char *stylesdir_after_install _GL_UNUSED,
+                    const char *default_style_file _GL_UNUSED)
+{
+}
+
+/* ------------------------------ From misc.h ------------------------------ */
+
+static inline styled_ostream_t
+styled_ostream_create (int fd, const char *filename,
+                       ttyctl_t tty_control _GL_UNUSED,
+                       const char *css_filename _GL_UNUSED)
+{
+  return fd_ostream_create (fd, filename, true);
+}
+
+static inline void
+libtextstyle_set_failure_exit_code (int exit_code _GL_UNUSED)
+{
+}
+
+#endif /* _TEXTSTYLE_H */