atbind(3)

NAME
atBindVersion, atBindSet, atBindCache, atBindNoMsg, atScanBinding, atBindTrace, atBindExpandMacro, atBindOptions, atBindModeOption, atBindSetArgv, atBindUsage - version binding

SYNOPSIS
#include <atfs.h>
#include <atfstk.h>

Af_key    *atBindVersion (char *name, *binding);

Af_set    *atBindSet (char *pattern, char *binding, int bindMode);

Af_set    *atBindCache (char *pattern, *binding);

int    atBindNoMsg;

int    atScanBinding (char *binding, char **resultStr, int *resultGen, int *resultRev, time_t *resultDate);

int    atBindTrace;

char    *(*atBindExpandMacro)(char *inputString);

int    atBindOptions (int argc, char **argv, int newArgc, char *(*newArgv[]));

int    atBindModeOption;

int    atBindSetArgv (int *argc, char *(*argv[]));

void    atBindUsage (char *extraText);

DESCRIPTION
atBindVersion performs a version binding, that means, it selects a unique version from a named history. It expects name to be either a string of the form historyName[binding] or a plain name. With a version bind directive (binding) given in brackets after the history name, the second argument is ignored. Otherwise the second argument is taken as version bind directive. With no binding given, atBindVersion performs the default binding. This may be explicitly defined by afBindOptions (see below), or it selects the most recent (modification/saving date) version. See below a list of different forms of version bind directives. atBindVersion returns the appropriate version key, if the bind operation leads to a unique version selection, otherwise NULL.

atBindSet works similar to atBindVersion, with the difference that the first argument may be a name pattern (a sh(1) pattern to be precise) instead of a unique file name. It uses the af_histories (manual page af_history(3)) call, to generate a list of history names from the given pattern. After that, it performs a version binding for each name with a version bind directive given either in square brackets or as binding argument (see above). atBindSet returns a set of version keys containing all found versions, or a NULL pointer if something went wrong.

Another option of atBindSet is nonunique version selection within a history. In this case, multiple versions from one history may be included in the result set. In detail atBindSet supports four options:

AT_BIND_UNIQUE
    Behave like atBindVersion for each name generated from pattern. Generates no error condition in case of nonunique or empty selection.

AT_BIND_SET
    (default) Do not require uniqueness. If more than one version from a history meets the binding specifications, all these versions will be included in the result set.

AT_BIND_LAST
    Selects the last (modification/saving date) version from the binding hit set of each history. The resulting hit set contains at most one version of each history involved in the bind operation.

AT_BIND_LASTSAVED
    Similar to AT_BIND_LAST but ignores busy versions.

atBindCache tries to bind versions from the derived object cache. It expects a pattern and binding argument similar to atBindSet.

The atBindNoMsg switch allows the output of version binding rules, generated by predicates like 'msg` or 'confirm`, to be suppressed. This can be done by setting atBindNoMsg TRUE. Initially, it is set FALSE. When evaluating a 'confirm` predicate, where user input is expected, with atBindNoMsg set true, the version binding algorithm proceeds without halting as if the user had accepted the default input.

atScanBinding scans the version bind directive binding. It returns the binding type, which is one of

AT_BIND_ALIAS
    A version alias (symbolic name). Example foo[release-2]. The alias name returned in resultStr resides in allocated memory.

AT_BIND_CACHEKEY
    A unique identifier for cached objects. This is automatically generated for each cached object and consists of three numbers (like foo.o[739564427.16390.22]).

AT_BIND_DATE
    A date specification. (see stMktime (manual pape sttime(3)) for a list of valid date formats) Examples: foo[Jan 8, 1993], foo[8.1.93]. The date is returned in resultDate.

AT_BIND_DEFAULT
    Default binding. This is the case when either an empty binding was given or something like foo[].

AT_BIND_RULE
    Version bind Rule. Example foo[bind_rule:]. A rule may also have the form foo[bind_rule(arg1,arg2,...argN):] additionally passing the given arguments to bind rule evaluation. The rule name returned in resultStr resides in allocated memory.

AT_BIND_VNUM
    Version number. Example foo[1.2]. The resulting generation and revision number are returned in resultGen and resultRev.

One important issue is, that each version alias will also be tried as rule name, if it turns out to be no known symbolic name. This implies that rule names may also be given without the trailing colon, when there are no naming conflicts with version aliases.

The atBindTrace switch enables tracing of each version bind operation when set TRUE. Trace output is sent to standard error. Initially, its value is FALSE.

The atBind module provides a hook for an external macro processor to preprocess any version bind rule just before applying it. The bind rule text may contain macro citations of the form $C or $(macroName) (like in Make-/Shapefiles) to be expanded by the external macro processor. This should expect any string containing macro citations as input and return a string with expanded macros. When assigned to the function variable atBindExpandMacro, the macro expansion routine will be invoked for each evaluated rule.

atBindOptions calls stParseArgs (manual page atparseargs(3)) with an internally defined standard option vector for command line version binding options. The vbind(1) manual page contains a description of these options. atBindOption should be called before parsing the application specific options It fetches the version binding options off the command line (input arguments argc and argv) and returns all remaining tokens (output arguments newArgc and newArgv). Return value is the number of erroneous options (e.g. with argument missing) found. A negative return value indicates an internal error, zero is returned un success.

atBindOptions defines the default version selection policy as given on the command line for the whole application. Each subsequent call of atBindVersion and atBindSet (see above) will conform to this policy unless an explicit version bind directive is given.

atBindSetArgv preprocesses a command line (arguments argc and argv) by evaluating and fetching off version binding options and replacing all filename arguments by bound filenames (e.g. foo[1.4]). It returns the number of arguments remaining on the command line.

atBindUsage calls stShortUsage (manual page atparseargs(3)) with the current program name, the bind standard options vector, and the given extraText. Result is a short usage description written to standard error.

DIAGNOSTICS
Upon error, the version binding functions (atBindVersion, atBindSet and atBindCache) return a null pointer. atScanBinding has no error conditions. atBindOptions and atBindSetArgv return -1 on error and a value greater or equal null on success. On any error, the variable atBindError is set true (non-zero), and an explaining message is copied to the atBindErrorMsg string buffer. The atBindError variable is cleared upon successfull calls, the message buffer remains unchanged.

FILES
$SHAPETOOLS/BindRules

SEE ALSO
atfstkintro(3), vbind(1), stparseargs(3)