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Data typing consists of two parts: A database that
stores data criteria and data attributes A collection of routines that query the database
The attributes of
data criteria, in alphabetical order, are: Table 9-1 “Data Criteria in
Order of Most Likely Use” describes
the data criteria in the order in which you are most likely to use
them. Table 9-1 Data Criteria in
Order of Most Likely Use Criteria | Description | Typical Usage |
|---|
DATA_ATTRIBUTES_NAME | The name of this type of data. This value
is a record_name in the data
attributes table. | POSTSCRIPT | NAME_PATTERN | A shell pattern-matching expression describing
the file names that could match this data. The default is an empty
string, which means to ignore file patterns in matching. | *.ps | CONTENT | Three values that are interpreted as
the start, type, and value fields of the magic file used by the
file utility. See the file(1)
man page for more information. The default is an empty field, which
means to ignore contents in matching. The following types are examples
of what can be matched: string, byte, short, long, and file name. | 0 string !% | MODE | A string of zero to four characters that
match the mode field of a stat
structure. See the stat(2)
man page for more information. The first character indicates: d
matches a directory s
matches a socket l
matches a symbolic link f
matches a regular file b
matches a block file c
matches a character special file | f&!x | | | The characters listed below can be either
the first or subsequent characters: r
matches any file with any of its user, group, or other read permission
bits set. w matches
any file with any of its user, group, or other write permission
bits set. x matches
any file with any of its user, group, or other execute or directory-search
permission bits set. | | | | For example, the MODE
field of frw matches any regular
file that is readable or writable; x
matches any file with any of its executable or search bits set. The
default is an empty field, which means to ignore the mode in matching. | | PATH_PATTERN | A shell pattern-matching expression describing
the absolute path names that could match this data. The default
is an empty string, which means to ignore path patterns in matching. | */mysubdir/* | LINK_NAME | See dtdtsfile(4)
man page. | | LINK_PATH | See dtdtsfile(4)
man page. | |
Some of the more common attributes of data types, in alphabetical
order, are: Table 9-1 “Data Criteria in
Order of Most Likely Use” describes
the data attributes in the order in which you are most likely to
use them. Table 9-2 Data Attributes
in Order of Most Likely Use Criteria | Description | Typical Usage |
|---|
DESCRIPTION | A human-readable description of this
data. If this field is NULL
or is not included in the data attribute record, the name of the
data attribute should be used. | This is a PostScript page description. | ICON | The name of the icon to be used for this
data. If this field is NULL
or is not included in the data attribute record, the standard icon
should be used. See dtdtsfile(4)
for more details on icon naming. | Dtps | PROPERTIES | Keywords to indicate properties for this
data. Valid values are invisible and visible. If this field is NULL
or is not included in the data attribute record, the visible property
should be assumed. Use this if you want to completely hide files
from the user. | invisible | ACTIONS | A list of actions that can be performed
on this data. This list refers to names in the action table for
actions that are to be presented to the user for objects of this
type. If this field is NULL
or is not included in the data attribute record, no action is available. | Open,Print | NAME_TEMPLATE Field | A string used to create a new file for
data of this type. The string is passed to sprintf(3)
with the file name as the single argument. The default is empty.
Contrast this field with the NAME_PATTERN
field of the data criteria table in that the template is used to
create a specific file, such as %s.c,
whereas the pattern is used to find files, such as *.c. | %s.ps | IS_EXECUTABLE Field | A string-Boolean value that tells users
of this data type that it can be executed as an application. If
IS_EXECUTABLE is set to true
(see DtDtsIsTrue())
the data is executable. If this field is NULL,
is not included in the data attribute record, or is not set to true,
then the data is considered not executable. | true | MOVE_TO_ACTION | The name of an action to be invoked when
an object is moved to the current object. | FILESYSTEM_MOVE | COPY_TO_ACTION | The name of an action to be invoked when
an object is copied to the current object. | FILESYSTEM_COPY | LINK_TO_ACTION | The name of an action to be invoked when
an object is linked to the current object. | FILESYSTEM_LINK | IS_TEXT | A string-Boolean value that tells users
of this data type that it is suitable for manipulation (viewing
or editing) in a text editor or text widget. The IS_TEXT
field is set to true (see
DtDtsIsTrue()) if the data
is textual in nature and if it should be presented to the user in
text form. Criteria for making this determination include whether
data consists of human language, is generated and maintained manually,
is usefully viewable and editable in a text editor, or contains
no (or only minimal) structuring and formatting information. | See Table 9-3 “IS_TEXT Attribute
Examples” for more examples. | | | If the IS_TEXT
field is true, the data is
eligible to be displayed directly by an application. That is, the
application can load the data directly into a text editing widget,
such as XmText. | | MEDIA Field | The names in the MEDIA
name space describe the form of the data itself. MEDIA
names are used as ICCCM selection targets, named in the MEDIA
field of the data-type records, and used in the type parameter of
ToolTalk Media Exchange messages. The MEDIA
name space is a subset of the name space of selection target atoms
as defined by the ICCCM. All selection targets that specify a data
format are valid MEDIA names,
and all valid MEDIA names
can be used directly as selection targets. Some selection targets
specify an attribute of the selection (for example, LIST_LENGTH)
or a side effect to occur (for example, DELETE),
rather than a data format. These attribute selection targets are
not part of the MEDIA name
space. | POSTSCRIPT | MIME_TYPE | MEDIA
is the desktop internal, unique name for data types. However, other
external naming authorities have also established name spaces. Multipurpose
Internet Message Extensions (MIME), as described in the referenced
MIME RFC, is one of those external registries, and is the standard-type
name space for the desktop mailer. | application/postscript | X400_TYPE | X.400 types are similar in structure
to the MEDIA type, but are
formatted using different rules and have different naming authorities. | 1 2 840 113556 3 2 850 | INSTANCE_ICON Field | The name of the icon to be used for this
instance of data, typically a value such as %name%.icon
[Bug in dtdtsfile(4) man
page, too.] If INSTANCE_ICON
is set, the application should use it instead of ICON.
If this field is NULL or
is not included in the data attribute record, the ICON
field should be used. | /myicondir/%name%.bm | DATA_HOST | The DATA_HOST
attribute is not a field that can be added to the data attributes
table in the *.dt file, but
it may be returned to an application reading attributes from the
table. The data-typing service adds this attribute automatically
to indicate the host system from which the data type was loaded.
If this field is NULL or
is not included in the data attribute record, the data type was
loaded from the local system. | |
The IS_TEXT field differs
from the text attribute of the MIME_TYPE
field, which is the MIME
content type, as described in the referenced MIME_ RFC.
The MIME content type determines
whether the data consists of textual characters or byte values.
If the data consists of textual characters, and the data is labeled
as text/*, the IS_TEXT
field determines whether it is appropriate for the data to be presented
to users in textual form. Table 9-3 “IS_TEXT Attribute
Examples” shows
some examples of IS_TEXT
usage with different MIME_TYPE
attributes. Table 9-3 IS_TEXT Attribute
Examples Description
and MIME_TYPE Attribute | IS_TEXT Value |
|---|
Human language encoded in ASCII with
MIME_TYPE
text/plain | IS_TEXT true | Human language encoded in E*UC, JIS,
Unicode, or an ISO Latin charset with MIME_TYPE text/plain;
charset=XXX | IS_TEXT true | CalendarAppointmentAttrs with a MIME_TYPE text/plain | IS_TEXT false | HyperText Markup Language (HTML) with
a MIME_TYPE
text/html | IS_TEXT true | PostScript with MIME_TYPE application/postscript | IS_TEXT false | C program source (C_SRC)
with MIME_TYPE text/plain | IS_TEXT true | Bitmaps and pixmaps (XBM
and XPM) with MIME_TYPE
text/plain | IS_TEXT false | Project or module files for the desktop
application building service with MIME_TYPE text/plain | IS_TEXT false | Shell scripts with MIME_TYPE text/plain | IS_TEXT false | Encoded text produced by uuencode(1)
with MIME_TYPE
text/plain | IS_TEXT false | *MIME_TYPE text/plain | IS_TEXT false |
See the dtdtsfile(4)
man page for more information about data-type attributes. |
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