WIP -- add simple bash completion support (#3131)

* add simple bash completion support

* add "completions" subdir to meson

* start extending completion to extra args

* file complete for every arg after 1

* add completion for enums, file, ints, doubles

* docs, try to improve directory completion

though dir completion is not working correctly, I'm not sure why

ChangeLog

@@ -18,6 +18,7 @@ master
 - threadpools size dynamically with load
 - operations can hint threadpool size
 - support for N-colour ICC profiles
+- add bash completions for "vips"
 - fits load and allows many more bands
 - fits write doesn't duplicate header fields
 - add @wrap to vips_text()

README.md

@@ -83,6 +83,8 @@ libvips must have `build-essential`, `pkg-config`, `libglib2.0-dev`,
 `libexpat1-dev`.  See the **Dependencies** section below for a full list
 of the libvips optional dependencies.
 
+There are basic bash completions in `completions/`, see the README in there.
+
 ## Cheatsheet 
 
 ```

completions/README.md

@@ -0,0 +1,28 @@
+# Shell completions for vips
+
+Basic shell completions for the `vips` program. Internally, these use the
+`-c` argument to `vips` to list argument options.
+
+## Example
+
+```
+$ vips relational<TAB>
+relational        relational_const  
+$ vips relational_const ~/pics/k2.<TAB>
+~/pics/k2.avif  ~/pics/k2.hdr   ~/pics/k2.pdf   ~/pics/k2.tif
+~/pics/k2.bmp   ~/pics/k2.heic  ~/pics/k2.pfm   ~/pics/k2.v
+~/pics/k2.csv   ~/pics/k2.jp2   ~/pics/k2.pgm   ~/pics/k2.vips
+~/pics/k2.fits  ~/pics/k2.jpg   ~/pics/k2.png   ~/pics/k2.webp
+~/pics/k2.flif  ~/pics/k2.jxl   ~/pics/k2.ppm   
+~/pics/k2.gif   ~/pics/k2.pbm   ~/pics/k2.ppt   
+$ vips relational_const ~/pics/k2.jpg x.v less<TAB>
+less    lesseq  
+$ vips relational_const ~/pics/k2.jpg x.v lesseq 12
+```
+
+## Install
+
+### `vips-completion.bash` 
+
+Usually copy to `/etc/bash_completion.d` to install, but it depends on your
+system.

completions/vips-completion.bash

@@ -0,0 +1,43 @@
+#/usr/bin/env bash
+
+# bash completions for the "vips" command
+
+# copy to /etc/bash_completion.d to install
+
+_vips_compgen_f()
+{
+  COMPREPLY=($(compgen -f -- "${COMP_WORDS[-1]}"))
+
+  if [ ${#COMPREPLY[@]} = 1 ]; then
+    local LASTCHAR=' '
+    if [ -d "$COMPREPLY" ]; then
+      LASTCHAR=/
+    fi
+
+    COMPREPLY=$(printf %q%s "$COMPREPLY" "$LASTCHAR")
+  else
+    for ((i=0; i < ${#COMPREPLY[@]}; i++)); do
+      if [ -d "${COMPREPLY[$i]}" ]; then
+        COMPREPLY[$i]=${COMPREPLY[$i]}/
+      fi
+    done
+  fi
+}
+
+_vips_completions()
+{
+  if [ ${#COMP_WORDS[@]} == "2" ]; then
+    COMPREPLY=($(compgen -W "$(vips -c)" "${COMP_WORDS[1]}"))
+  else
+    local args=($(vips -c ${COMP_WORDS[1]}))
+    local arg_type=${args[${#COMP_WORDS[@]}-3]}
+    if [ $arg_type == "file" ]; then
+      _vips_compgen_f
+    elif [[ $arg_type = word:* ]]; then
+      local options=$(echo $arg_type | sed 's/word://' | sed 's/|/ /g')
+      COMPREPLY=($(compgen -W "${options[@]}" "${COMP_WORDS[-1]}"))
+    fi
+  fi
+}
+
+complete -F _vips_completions vips

libvips/iofuncs/operation.c

@@ -360,7 +360,6 @@ vips_operation_pspec_usage( VipsBuf *buf, GParamSpec *pspec )
 		vips_buf_appendf( buf, "%s", _( "max" ) );
 		vips_buf_appendf( buf, ": %d\n", pspec_int->maximum ); 
 	}
-
 }
 
 static void *

man/vips.1

@@ -33,6 +33,11 @@ loaded automatically.
 .B -v, --version
 Show VIPS version.
 
+.TP
+.B -c NAME, --completion NAME
+Print completions for 
+.B NAME
+
 .SH COMMANDS
 
 .TP
@@ -41,7 +46,7 @@ Execute a named operation, for example add.
 
 .SH EXAMPLES
 
-Run a vips8 operation. Operation options must follow the operation name.
+Run a vips operation. Operation options must follow the operation name.
 
   $ vips insert lena.v lena2.v out.v 0 0 --background "128 0 0"
 

tools/vips.c

@@ -45,6 +45,8 @@
  * 18/6/20 kleisauke
  * 	- avoid using vips7 symbols
  * 	- remove deprecated vips7 C++ generator
+ * 1/11/22
+ * 	- add "-c" flag
  */
 
 /*
@@ -170,6 +172,119 @@ parse_main_option_list( const gchar *option_name, const gchar *value,
 	exit( 0 );
 }
 
+static void *
+list_operation( GType type, void *user_data )
+{
+	VipsObjectClass *class = VIPS_OBJECT_CLASS( g_type_class_ref( type ) );
+
+	if( G_TYPE_IS_ABSTRACT( type ) )
+		return( NULL ); 
+	if( class->deprecated )
+		return( NULL );
+	if( VIPS_OPERATION_CLASS( class )->flags & VIPS_OPERATION_DEPRECATED )
+		return( NULL ); 
+
+	printf( "%s\n", class->nickname );
+
+	return( NULL );
+}
+
+static void *
+list_operation_arg( VipsObjectClass *object_class, 
+	GParamSpec *pspec, VipsArgumentClass *argument_class,
+	void *_data1, void *_data2 )
+{
+	GType type = G_PARAM_SPEC_VALUE_TYPE( pspec );
+
+	if( !(argument_class->flags & VIPS_ARGUMENT_CONSTRUCT) ||
+		(argument_class->flags & VIPS_ARGUMENT_DEPRECATED) )
+		return( NULL ); 
+
+	/* We don't try to complete options, though maybe we should.
+	 */
+	if( !(argument_class->flags & VIPS_ARGUMENT_REQUIRED) )
+		return( NULL ); 
+
+	/* These are the pspecs that vips uses that have interesting values.
+	 */
+	if( G_IS_PARAM_SPEC_ENUM( pspec ) ) {
+		GTypeClass *class = g_type_class_ref( type );
+
+		GEnumClass *genum;
+		int i; 
+
+		/* Should be impossible, no need to warn.
+		 */
+		if( !class )
+			return( NULL );
+
+		genum = G_ENUM_CLASS( class );
+
+		printf( "word:" );
+
+		/* -1 since we always have a "last" member.
+		 */
+		for( i = 0; i < genum->n_values - 1; i++ ) {
+			if( i > 0 )
+				printf( "|" );
+			printf( "%s", genum->values[i].value_nick );
+		}
+
+		printf( "\n" ); 
+	}
+	else if( G_IS_PARAM_SPEC_BOOLEAN( pspec ) ) 
+		printf( "word:true|false\n" );
+	else if( G_IS_PARAM_SPEC_DOUBLE( pspec ) ) {
+		GParamSpecDouble *pspec_double = (GParamSpecDouble *) pspec;
+
+		printf( "word:%g\n", pspec_double->default_value ); 
+	}
+	else if( G_IS_PARAM_SPEC_INT( pspec ) ) {
+		GParamSpecInt *pspec_int = (GParamSpecInt *) pspec;
+
+		printf( "word:%d\n", pspec_int->default_value ); 
+	}
+	else if( G_IS_PARAM_SPEC_OBJECT( pspec ) ) 
+		/* Eg. an image input or output.
+		 */
+		printf( "file\n" );
+	else
+		/* We can offer no useful suggestion for eg. array_int etc.
+		 */
+		printf( "none\n" );
+
+	return( NULL );	
+}
+
+static gboolean
+parse_main_option_completion( const gchar *option_name, const gchar *value, 
+	gpointer data, GError **error )
+{
+	VipsObjectClass *class;
+
+	if( value &&
+		(class = (VipsObjectClass *) vips_type_map_all( 
+			g_type_from_name( "VipsOperation" ), 
+			test_nickname, (void *) value )) )  
+		vips_argument_class_map( class,
+			(VipsArgumentClassMapFn) list_operation_arg, 
+			NULL, NULL );
+	else if( value ) {
+		vips_error( g_get_prgname(), 
+			_( "'%s' is not the name of a vips operation" ), 
+			value );
+		vips_error_g( error );
+
+		return( FALSE );
+	}
+	else {
+		vips_type_map_all( g_type_from_name( "VipsOperation" ), 
+			list_operation, NULL );
+	}
+
+	exit( 0 );
+}
+
 static GOptionEntry main_option[] = {
 	{ "list", 'l', G_OPTION_FLAG_OPTIONAL_ARG, G_OPTION_ARG_CALLBACK, 
 		(GOptionArgFunc) parse_main_option_list, 
@@ -180,6 +295,10 @@ static GOptionEntry main_option[] = {
 		N_( "PLUGIN" ) },
 	{ "version", 'v', 0, G_OPTION_ARG_NONE, &main_option_version, 
 		N_( "print version" ), NULL },
+	{ "completion", 'c', G_OPTION_FLAG_OPTIONAL_ARG, G_OPTION_ARG_CALLBACK, 
+		(GOptionArgFunc) parse_main_option_completion, 
+		N_( "print completions" ), 
+		N_( "BASE-NAME" ) },
 	{ NULL }
 };