diff options
Diffstat (limited to 'libical/doc/UsingLibical.txt')
| -rw-r--r-- | libical/doc/UsingLibical.txt | 632 |
1 files changed, 449 insertions, 183 deletions
diff --git a/libical/doc/UsingLibical.txt b/libical/doc/UsingLibical.txt index ea5726f401..6dc4958a74 100644 --- a/libical/doc/UsingLibical.txt +++ b/libical/doc/UsingLibical.txt @@ -4,7 +4,7 @@ Using Libical Eric Busboom (eric@softwarestudio.org) -November 2000 +January 2001 @@ -12,11 +12,11 @@ November 2000 Libical is an Open Source implementation of the iCalendar protocols and protocol data units. The iCalendar specification describes how -calendar clients can communicate with calendar servers for users can +calendar clients can communicate with calendar servers so users can store their calendar data and arrange meetings with other users. -Libical implements RFC2445 and RFC2446. Eventually, it will also implement -iRIP and CAP. +Libical implements RFC2445, RFC2446 and some of RFC2447 and the CAP +draft. This documentation assumes that you are familiar with the iCalendar standards RFC2445 and RFC2446. these specifications are online on @@ -55,16 +55,15 @@ my version of the library if they are similarly dual-licensed. A lot of the documentation for this library is in the form of example code. These examples are in the "examples" directory of the distribution. -Also look in "src/test" for more annotated examples. +Also look in "src/test" for additional annotated examples. 2 Building the Library -Libical uses autoconf to generate makefiles, although it uses none -of the autoconf flags to influence the compilation. It should built -with no adjustments on Linux, FreeBSD and Solaris under gcc. Some -version have been successfully been build on MacOS, Solaris and UnixWare -without gcc, but you may run into problems with a particular later -version. +Libical uses autoconf to generate makefiles. It should built with no +adjustments on Linux, FreeBSD and Solaris under gcc. Some version +have been successfully been build on MacOS, Solaris, UnixWare, And +Tru64 UNIX without gcc, but you may run into problems with a particular +later version. For a more complete guide to building the library, see the README file in the distribution. @@ -86,15 +85,18 @@ and the "ROLE" parameter specifies that Mr Big is the chair of the meetings associated with this property. Components are groups of properties that represent the core objects -of a calendar system, such as events or timezones. - -The central goal of libical is to parse iTIP data into an internal -representation of Components, Properties, Parameters an Values, and -to allow the user to manipulate the data in various ways +of a calendar system, such as events or timezones. Components are +delimited by "BEGIN" and "END" tags. When a component is sent across a network, if it is un-encrypted, it will look something like: +BEGIN:VCALENDAR + +METHOD:REQUEST + +PRODID: -//hacksw/handcal//NONSGML v1.0//EN + BEGIN:VEVENT DTSTAMP:19980309T231000Z @@ -125,43 +127,84 @@ LOCATION:1CP Conference Room 4350 END:VEVENT +END:VCALENDAR + +Note that components can be nested; this example has both a VCALENDAR +and a VEVENT component, one nested inside the other. + 3.1 Core iCal classes -3.1.1 Components +Libical is an object-based, data-oriented library. Nearly all of the +routines in the library are associated with an opaque data types and +perform some operation on that data type. Although the library does +not actually have classes, we will use those terms since the behavior +of these associations of data and routines is very similar to a class. + +3.1.1 Properties + +Properties are represented with the icalproperty class and its many +"derived" classes with on "derived" class per property type in RFC2445. +Again, there is no actual inheritance relations, but there are clusters +of routines that make this term useful. A property is a container +for a single value and a set of parameters. -3.1.2 Properties +3.1.2 Components + +In libical, components are represented with the icalcomponent class. +Icalcomponent is a container for a set of other components and properties. 3.1.3 Values +Values are represented in a similar way to properties; a base class +and many "derived " classes. A value is essentially a abstract handle +on a single fundamental type, a structure or a union. + 3.1.4 Parameters +Parameters are represetned in a similar way to properties, except that +they contain only one value + 3.2 Other elements of libical In addition to the core iCal classes, libical has many other types, structures, classes that aid in creating and using iCal components. -3.2.1 Enumerations +3.2.1 Enumerations and types + +Libical is strongly typed, soo every component, property, parameter, +and value type has an enumeration, and some have an associated structure +or union. -3.2.2 Types +3.2.2 The parser -3.2.3 The parser +The libical parser offers a variety of ways to convert RFC2445 text +into a libical iinsteral component structure. the parser can parse +blocks of text as a string, or it can parse lin-by-line. -3.2.4 Restrictions +3.2.3 Error objects -3.2.5 Error objects +Libical has a substantial error reporting system for both programming +errors and component usage errors. -3.2.6 Memory Management +3.2.4 Memory Management -3.2.7 Storage classes +Since many of libicals interfaces return strings, the library has its +own memory management system to elimiate the need to free every string +returned from the libraru. + +3.2.5 Storage classes + +The library also offers several classes to store components to flies, +memory or databases. 4 Differences From RFCs Libical has been designed to follow the standards as closely as possible, -so that the key objects in the standards are also keey objects in -the library. However, there are a few areas where the specifications -are (arguably) irregular, and following them exactly would result -in an unfriendly interface. These deviations make libical easier to -use by maintaining a self-similar interface. +so that the key objects in the standards are also key objects in the +library. However, there are a few areas where the specifications are +(arguably) irregular, and following them exactly would result in an +unfriendly interface. These deviations make libical easier to use +by maintaining a self-similar interface. 4.1 Pseudo Components @@ -176,7 +219,7 @@ but is not defined as a component in RFC2445. ( See RFC2445, page Standard iCAL components all start with the letter "V," while pseudo components start with"X." -There are also pseudo components that are conceptually derived classess +There are also pseudo components that are conceptually derived classes of VALARM. RFC2446 defines what properties may be included in each component, and for VALARM, the set of properties it may have depends on the value of the ACTION property. @@ -198,7 +241,7 @@ types make it difficult to create routines to return the value associated with a property. It is natural to have interfaces that would return the value of a property, -but it is cumbersone for a single routine to return multiple types. +but it is cumbersome for a single routine to return multiple types. So, in libical, properties that can have multiple types are given a single type that is the union of their RFC2445 types. For instance, in libical, the value of the TRIGGER property resolves to struct icaltriggertype. @@ -230,20 +273,18 @@ for CATEGORIES illegal. However when you convert a component to a string, the library will collect all of the CATEGORIES properties into one. -5 Implementation Limitations - -6 Using libical +5 Using libical -6.1 Creating Components +5.1 Creating Components There are three ways to create components in Libical: creating individual objects and assembling them, building entire objects in massive vaargs calls, and parsing a text file containing iCalendar data. -6.1.1 Constructor Interfaces +5.1.1 Constructor Interfaces -Using constructor interfaces, you create each of the objects seperately -and them assemble them in to components: +Using constructor interfaces, you create each of the objects separately +and then assemble them in to components: icalcomponent *event; @@ -259,11 +300,11 @@ prop = icalproperty_new_dtstamp(atime) ; icalcomponent_add_property(event, prop); -prop = icalproperty_new_uid(strdup("guid-1.host1.com")) ); +prop = icalproperty_new_uid(''guid-1.host1.com'') ); icalcomponent_add_property(event,prop); -prop=icalproperty_new_organizer(strdup("mrbig@host.com")); +prop=icalproperty_new_organizer(''mrbig@host.com''); param = icalparameter_new_role(ICAL_ROLE_CHAIR) @@ -271,16 +312,12 @@ icalproperty_add_parameter(prop, param); icalcomponent_add_property(event,prop); -While we are on this example, you should notice that libical uses a -semi-object-oriented style of interface. Most things you work with -are objects, that are instantiated with a constructor that has "new" -in the name. Also note that, other than the object reference, most -structure data is passed in to libical routines by value. Strings, -of course, are passed in by reference, but libical will take ownership -of the memory, so you had beter strdup() the data unless you want -a core dump when the memory is freed for the second time. Libical -has some complex but very regular memory handling rules. These are -detailed in section [sec:memory]. +Notice that libical uses a semi-object-oriented style of interface. +Most things you work with are objects, that are instantiated with +a constructor that has "new" in the name. Also note that, other than +the object reference, most structure data is passed in to libical +routines by value. Libical has some complex but very regular memory +handling rules. These are detailed in section [sec:memory]. If any of the constructors fail, they will return 0. If you try to insert 0 into a property or component, or use a zero-valued object @@ -288,12 +325,12 @@ reference, libical will either silently ignore the error or will abort with an error message. This behavior is controlled by a compile time flag (ICAL_ERRORS_ARE_FATAL), and will abort by default. -6.1.2 vaargs Constructors +5.1.2 vaargs Constructors -There is another way to create complex components, which is arguable +There is another way to create complex components, which is arguably more elegant, if you are not horrified by varargs. The varargs constructor -interface all you to create intricate components in a single block -of text. +interface allows you to create intricate components in a single block +of code. Here is the previous examples in the vaargs style. calendar = @@ -301,11 +338,11 @@ of text. ICAL_VCALENDAR_COMPONENT, - icalproperty_new_version(strdup("2.0")), + icalproperty_new_version(''2.0''), - icalproperty_new_prodid(strdup( + icalproperty_new_prodid( - "-//RDU Software//NONSGML HandCal//EN")), + ''-//RDU Software//NONSGML HandCal//EN''), icalcomponent_vanew( @@ -313,11 +350,11 @@ of text. icalproperty_new_dtstamp(atime), - icalproperty_new_uid(strdup("guid-1.host1.com")), + icalproperty_new_uid(''guid-1.host1.com''), icalproperty_vanew_organizer( - strdup("mrbig@host.com"), + ''mrbig@host.com''), icalparameter_new_role(ICAL_ROLE_CHAIR), @@ -327,7 +364,7 @@ of text. icalproperty_vanew_attendee( - strdup("employee-A@host.com"), + ''employee-A@host.com'', icalparameter_new_role( @@ -341,9 +378,9 @@ of text. ), - icalproperty_new_location(strdup( + icalproperty_new_location( - "1CP Conference Room 4350")), + "1CP Conference Room 4350"), 0 @@ -353,14 +390,14 @@ of text. ); -This form is similar to the regular constructor, except that they have -"vanew" instead of "new" in the name. The arguments are similar too, -except that the component contstructor can have a list of properties, -and the property constructor can have a list or parameters. Be sure +This form is similar to the constructor form , except that the constructors +have "vanew" instead of "new" in the name. The arguments are similar +too, except that the component constructor can have a list of properties, +and the property constructor can have a list of parameters. Be sure to terminate every list with a '0', or your code will crash, if you are lucky. -6.1.3 Parsing Text Files +5.1.3 Parsing Text Files The final way to create components will probably be the most common; you can create components from RFC2445 compliant text. If you have @@ -368,9 +405,14 @@ the string in memory, use icalcomponent* icalparser_parse_string(char* str); -This may seem wasteful if you want to pull a large component off of -the network; you may prefer to parse the component line by line. This -is possible too by using: +If the string contains only one component, the parser will return the +component in libical form. If the string contains multiple components, +the multiple components will be returned as the children of an ICAL_XROOT_COMPONENT +component. + +Parsing a whole string may seem wasteful if you want to pull a large +component off of the network or from a file; you may prefer to parse +the component line by line. This is possible too by using: icalparser* icalparser_new(); @@ -384,7 +426,8 @@ icalparser_set_gen_data(parser,stream) These routines will construct a parser object to which you can add lines of input and retrieve any components that the parser creates -from the input. For an example: +from the input. These routines work by specifing an adaptor routine +to get string data from a source. For an example: char* read_stream(char *s, size_t size, void *d) @@ -435,36 +478,37 @@ with icalparser_set_gen_data() and icalparser_get_line(). In this example, the routine read_stream() will fetch the next line from a stream, with the stream passed in as the void* parameter d. The parser calls read_stream() from icalparser_get_line(), but it also needs -to know what stream to use. This is set by the call to icalparser_set_gen_data(). +to know what stream to use. This is set by the call to icalparser_set_gen_data(). +By using a different routine for read_stream or passing in different +data with icalparser_set_gen_data, you can connect to any data source. -Using the same mechanism, other implmentations could read from memory +Using the same mechanism, other implementations could read from memory buffers, sockets or other interfaces. Since the example code is a very common way to use the parser, there -is a convienience routine; +is a convenience routine; icalcomponent* icalparser_parse(icalparser *parser, - char* (*line_gen_func)(char *s, size_t sise, void* + char* (*line_gen_func)(char *s, size_t size, void* d)) To use this routine, you still must construct the parser object and pass in a reference to a line reading routine. If the parser can create a single component from the input, it will return a pointer to the newly constructed component. If the parser can construct multiple -cmponents from the input, it will return a reference to an XROOT component -( of type ICAL_XROOT_COMPONENT.) This XROOT component will hold all -of the components constructed from the input as children. See section -6.2.2 for how to iterate through the child components. +components from the input, it will return a reference to an XROOT +component ( of type ICAL_XROOT_COMPONENT.) This XROOT component will +hold all of the components constructed from the input as children. -6.2 Accessing Components +5.2 Accessing Components Given a reference to a component, you probably will want to access -the properties, parameters and values inside. Libical interface let +the properties, parameters and values inside. Libical interfaces let you find sub-component, add and remove sub-components, and do the same three operations on properties. -6.2.1 Finding Components +5.2.1 Finding Components To find a sub-component of a component, use: @@ -498,7 +542,7 @@ As you might guess, if there is more than one subcomponent of the type you have chosen, this routine will return only the first. to get at the others, you need to iterate through the component. -6.2.2 Interating Through Components +5.2.2 Iterating Through Components Iteration requires a second routine to get the next subcomponent after the first: @@ -528,13 +572,13 @@ This code bit wil iterate through all of the subcomponents in 'comp' but you can select a specific type of component by changing ICAL_ANY_COMPONENT to another component type. -6.2.3 Using Component Iterators +5.2.3 Using Component Iterators The iteration model in the previous section requires the component to keep the state of the iteration. So, you could not use this model to perform a sorting operations, since you'd need two iterators and there is only space for one. If you ever call icalcomponent_get_first_component() -which an iteration is in progress, the pointer will be reset to the +when an iteration is in progress, the pointer will be reset to the beginning. To solve this problem, there are also external iterators for components. @@ -553,7 +597,7 @@ icalcomponent* icalcompiter_prior(icalcompiter* i); icalcomponent* icalcompiter_deref(icalcompiter* i); The _begin_() and _end_() routines return a new iterator that points -to the begining and ending of the list of subcomponent for the given +to the beginning and ending of the list of subcomponent for the given component, and the kind argument works like the kind argument for internal iterators. @@ -579,17 +623,16 @@ for( } -6.2.4 Removing Components +5.2.4 Removing Components -Libical component have internal iterators, so you can only have one -iteration over a component at a time. Removing an element from a list -while iterating through the list can cause problems, since you will -probably be removing the element that the internal iterator points -to. The _remove() routine will keep the iterator valid by moving it -to the next component, but in a normal loop, this will result in two -advances per iteration, and you will remove only every other component. - To avoid the problem, you will need to step the iterator ahead of -the element you are going to remove, like this: +Removing an element from a list while iterating through the list with +the internal iterators can cause problems, since you will probably +be removing the element that the internal iterator points to. The +_remove() routine will keep the iterator valid by moving it to the +next component, but in a normal loop, this will result in two advances +per iteration, and you will remove only every other component. To +avoid the problem, you will need to step the iterator ahead of the +element you are going to remove, like this: for(c = icalcomponent_get_first_component(parent_comp,ICAL_ANY_COMPONENT); @@ -626,7 +669,7 @@ while((c=icalcomponent_get_current_component(c)) != 0 ){ } -6.2.5 Working with properties and parameters +5.2.5 Working with properties and parameters Finding, iterating and removing properties works the same as it does for components, using the property-specific or parameter-specific @@ -656,6 +699,8 @@ void icalcomponent_remove_property( icalproperty* property); +For parameters: + icalparameter* icalproperty_get_first_parameter( icalproperty* prop, @@ -680,26 +725,29 @@ void icalproperty_remove_parameter( icalparameter_kind kind); -6.2.6 Working with values +Note that since there should be only one parameter of each type in +a property, you will rarely need to use icalparameter_get_nect_paameter. + +5.2.6 Working with values Values are typically part of a property, although they can exist on -their own. You can maniplulate them either as part of the property -or independantly. +their own. You can manipulate them either as part of the property +or independently. -The most common way to work with values to is to maniplate them from +The most common way to work with values to is to manipulate them from they properties that contain them. This involves fewer routine calls and intermediate variables than working with them independently, and it is type-safe. For each property, there are a _get_ and a _set_ routine that access -the internal value. For instnace, for the UID property, the routines +the internal value. For instanace, for the UID property, the routines are: void icalproperty_set_uid(icalproperty* prop, const char* v) const char* icalproperty_get_uid(icalproperty* prop) -For multivalued properties, like ATTACH, the value type is usually +For multi-valued properties, like ATTACH, the value type is usually a struct or union that holds both possible types. If you want to work with the underlying value object, you can get and @@ -709,10 +757,10 @@ icalvalue* icalproperty_get_value (icalproperty* prop) void icalproperty_set_value(icalproperty* prop, icalvalue* value); -Icalproperty_get_value() will return a reference that you can manipluate +Icalproperty_get_value() will return a reference that you can manipulate with other icalvalue routines. Most of the time, you will have to know what the type of the value is. For instance, if you know that -the value is a DATETIME type, you can manipluate it with: +the value is a DATETIME type, you can manipulate it with: struct icaltimetype icalvalue_get_datetime(icalvalue* value); @@ -726,18 +774,23 @@ void icalproperty_set_x(icalproperty* prop, char* v); char* icalproperty_get_x(icalproperty* prop); -6.2.7 Working with parameters +All X properties have the type of ICAL_X_PROPERTY, so you will need +these routines to get and set the name of the property: + +char* icalproperty_get_x_name(icalproperty* prop) -6.2.8 Checking Component Validity +void icalproperty_set_x_name(icalproperty* prop, char* name); + +5.2.7 Checking Component Validity RFC 2446 defines rules for what properties must exist in a component -to be used for transfering scheduling data. Most of these rules relate +to be used for transferring scheduling data. Most of these rules relate to the existence of properties relative to the METHOD property, which -declares what operation a remote reciever should use to process a +declares what operation a remote receiver should use to process a component. For instance, if the METHOD is REQUEST and the component -is a VEVENT, the sender is probably asking the reciever to join in +is a VEVENT, the sender is probably asking the receiver to join in a meeting. In this case, RFC2446 says that the component must specify -a start time (DTSTART) and list the reciever as an attendee (ATTENDEE). +a start time (DTSTART) and list the receiver as an attendee (ATTENDEE). Libical can check these restrictions with the routine: @@ -751,9 +804,9 @@ When this routine runs, it will insert new properties into the component to indicate any errors it finds. See section 6.5.3, X-LIC-ERROR for more information about these error properties. -6.2.9 Converting Components to Text +5.2.8 Converting Components to Text -To create an RFC2445 compliant text representtion of an object, use +To create an RFC2445 compliant text representation of an object, use one of the *_as_ical_string() routines: char* icalcomponent_as_ical_string (icalcomponent* component) @@ -769,16 +822,17 @@ it will cascade and convert all of the parameters, properties and values that are attached to the root component. Icalproperty_as_ical_string() will terminate each line with the RFC2445 -specified line terminator "\r\n" However, if you compile with the symbol -ICAL_UNIX_NEWLINE defined, it will terminate lines with "\n" +specified line terminator "\\n" However, if you compile with the symbol +ICAL_UNIX_NEWLINE undefined, ( it is defined by default) it will terminate +lines with "\\n\\r" Remember that the string returned by these routines is owned by the library, and will eventually be re-written. You should copy it if you want to preserve it. -6.3 Time +5.3 Time -6.3.1 Time structure +5.3.1 Time structure LIbical defines it's own time structure for storing all dates and times. It would have been nice to re-use the C library's struct tm, but that @@ -808,7 +862,31 @@ time values. The is_utc field distinguishes between times UTC and a local time zone. The is_date field indicates if the intra-day fields hold valid data. -6.3.2 Time manipulating routines +5.3.2 Creating time structures + +There are several ways to create a new icaltimetype structure: + +struct icaltimetype icaltime_from_string(const char* str); + +struct icaltimetype icaltime_from_timet(time_t v, int is_date); + +struct icaltimetype icaltime_from_int(int v, int is_date, int is_utc); + +Icaltime_from_string takes any RFC2445 compliant time string: + +struct icaltimetype tt = icaltime_from_string("19970101T103000"); + +Icaltime_from_timet takes a timet value, representing seconds past +the POSIX epoch, and a flag to indicate if the time is a date. Dates +have an identical structure to a time, but they time portion ( hours, +minuts and seconds ) is always 00:00:00. Dates act differently in +sorting an comparision, and they have a different string representation +in RFC2445. + +The icaltime_from_int is like icaltime_from_timet, but with an arbitrary +epoch. This routine was a mistake and is deprecated. + +5.3.3 Time manipulating routines The null time value is used to indicate that the data in the structure is not a valid time. @@ -825,6 +903,16 @@ over into the next larger field when the structure is normalized. struct icaltimetype icaltime_normalize(struct icaltimetype t); +Normalizing allows you to do arithmetic operations on time values. + +struct icaltimetype tt = icaltime_from_string("19970101T103000"); + +tt.days +=3 + +tt.second += 70; + +tt = icaltime_normalize(tt); + There are several routines to get the day of the week or month, etc, from a time structure. @@ -844,14 +932,10 @@ year); short icaltime_days_in_month(short month,short year); Two routines convert time structures to and from the number of seconds -since the POSIX epoch. The is_date field indicates wether or not the -hour, minute and second fields should be used in the conversion, and -is_utc indicates if the value should be converted to a local time -or a UTC time, using the operating system suppled notion of the local -timezone. +since the POSIX epoch. The is_date field indicates whether or not +the hour, minute and second fields should be used in the conversion. -struct icaltimetype icaltime_from_timet(time_t v, int is_date, int -is_utc); +struct icaltimetype icaltime_from_timet(time_t v, int is_date); time_t icaltime_as_timet(struct icaltimetype); @@ -866,7 +950,7 @@ tzid field must be a timezone name from the Olsen database, such as The utc_offset routine returns the offset of the named time zone from UTC, in seconds. -The tt parmeter in the fonllowing routines indicates the date on which +The tt parameter in the following routines indicates the date on which the conversion should be made. The tt parameter is necessary because timezones have many different rules for when daylight savings time is used, and these rules can change over time. So, for a single timezone @@ -874,20 +958,210 @@ one year may have daylight savings time on March 15, but for other years March 15 may be standard time, and some years may have standard time all year. -int icaltime_utc_offset(struct icaltimetype tt, char* tzid) +int icaltime_utc_offset(struct icaltimetype tt, char* tzid); + +int icaltime_local_utc_offset(); struct icaltimetype icaltime_as_utc(struct icaltimetype tt,char* tzid); struct icaltimetype icaltime_as_zone(struct icaltimetype tt,char* tzid); -6.4 Storing Objects +struct icaltimetype icaltime_as_local(struct icaltimetype tt); + +5.4 Storing Objects -The libical distribution inclues a seperate library, libicalss, that +The libical distribution includes a separate library, libicalss, that allows you to store iCal component data to disk in a variety of ways. -This library is documented seperately. ( & currently, not at all. -) +This library also includes code to implement the CSTP protocol of +CAP and has some routines for deciphering incomming messages. + +The file storage routines are organized in an inheritance heirarchy +that is rooted in icalset, with the derived class icalfileset and +icaldirset. Icalfileset stores components to a file, while icaldirset +stores components to multiple files, one per month based on DTSTAMP. +Other storages classess, for storage to a heap or a mysql database +are planned for the future. + +All of the icalset derived classes have the same interface: + +icaldirset* icaldirset_new(const char* path); + +void icaldirset_free(icaldirset* store); + +const char* icaldirset_path(icaldirset* store); + +void icaldirset_mark(icaldirset* store); + +icalerrorenum icaldirset_commit(icaldirset* store); + +icalerrorenum icaldirset_add_component(icaldirset* store, icalcomponent* +comp); + +icalerrorenum icaldirset_remove_component(icaldirset* store, icalcomponent* +comp); + +int icaldirset_count_components(icaldirset* store, icalcomponent_kind +kind); + +icalerrorenum icaldirset_select(icaldirset* store, icalcomponent* gauge); + +void icaldirset_clear(icaldirset* store); + +icalcomponent* icaldirset_fetch(icaldirset* store, const char* uid); + +int icaldirset_has_uid(icaldirset* store, const char* uid); + +icalcomponent* icaldirset_fetch_match(icaldirset* set, icalcomponent +*c); + +icalerrorenum icaldirset_modify(icaldirset* store, icalcomponent *oldc, +icalcomponent *newc); + +icalcomponent* icaldirset_get_current_component(icaldirset* store); + +icalcomponent* icaldirset_get_first_component(icaldirset* store); + +icalcomponent* icaldirset_get_next_component(icaldirset* store); + +5.4.1 Creating a new set + +You can create a new set from either the base class or the direved +class. From the base class use one of: + +icalset* icalset_new_file(const char* path); + +icalset* icalset_new_dir(const char* path); + +icalset* icalset_new_heap(void); -6.5 <sec:memory>Memory Management +icalset* icalset_new_mysql(const char* path); + +You can also create a new set based on the derived class, For instance, +with icalfileset: + +icalfileset* icalfileset_new(const char* path); + +icalfileset* icalfileset_new_open(const char* path, int flags, mode_t +mode); + +Icaset_new_file is identical to icalfileset_new. BOth routines will +open an existing file for readinga and writing, or create a new file +if it does not exist. Icalfilset_new_open takes the same arguments +as the open() system routine and behaves in the same way. + +The icalset and icalfilset objects are somewhat interchangable -- you +can use an icalfileset* as an argument to any of the icalset routines. + +The following examples will all use icalfileset routines; using the +other icalset derived classess will be similar. + +5.4.2 Adding, Finding and Removing Components + +To add components to a set, use: + +icalerrorenum icalfileset_add_component(icalfileset* cluster, icalcomponent* +child); + +The fileset keeps an inmemory copy of the components, and this set +must be written back to the file ocassionally. There are two routines +to manage this: + +void icalfileset_mark(icalfileset* cluster); + +icalerrorenum icalfileset_commit(icalfileset* cluster); + +Icalfileset_mark indicates that the in-memory components have changed. +Calling the _add_component routine will call _mark automatically, +but you may need to call it yourself if you have made a change to +an existing component. The _commit routine writes the data base to +disk, but only if it is marked. The _commit routine is called automatically +when the icalfileset is freed. + +To iterate through the components in a set, use: + +icalcomponent* icalfileset_get_first_component(icalfileset* cluster); + +icalcomponent* icalfileset_get_next_component(icalfileset* cluster); + +icalcomponent* icalfileset_get_current_component (icalfileset* cluster); + +These routines work like the corresponding routines from icalcomponent, +except that their output is filtered through a gauge. A gauge is a +test for the properties within a components; only components that +pass the test are returned. A gauge can be constructed from a MINSQL +string with: + +icalgauge* icalgauge_new_from_sql(char* sql); + +Then, you can add the gauge to the set with : + +icalerrorenum icalfileset_select(icalfileset* store, icalgauge* gauge); + +Here is an example that puts all of these routines together: + +void test_fileset() + +{ + + icalfileset *fs; + + icalcomponent *c; + + int i; + + char *path = "test_fileset.ics"; + + icalgauge *g = icalgauge_new_from_sql( + + "SELECT * FROM VEVENT WHERE DTSTART > '20000103T120000Z' AND +DTSTART <= '20000106T120000Z'"); + + + + fs = icalfileset_new(path); + + + + for (i = 0; i!= 10; i++){ + + c = make_component(i); /* Make a new component where DTSTART +has month of i */ + + icalfileset_add_component(fs,c); + + } + + icalfileset_commit(fs); /* Write to disk */ + + icalfileset_select(fs,g); /* Set the gauge to filter components +*/ + + + + for (c = icalfileset_get_first_component(fs); + + c != 0; + + c = icalfileset_get_next_component(fs)){ + + struct icaltimetype t = icalcomponent_get_dtstart(c); + + + + printf("%s\n",icaltime_as_ctime(t)); + + } + + icalfileset_free(fs); + +} + +5.4.3 Other routines + +There are several other routines in the icalset interface, but they +not fully implemented yet. + +5.5 <sec:memory>Memory Management Libical relies heavily on dynamic allocation for both the core objects and for the strings used to hold values. Some of this memory the library @@ -902,7 +1176,7 @@ library. Here is a summary of the memory rules. call the corresponding *_free routine to free the memory. ( Use icalcomponent_free() to free objects created with icalcomponent_new()) -3) If the function name has "add" in it, the caller is transfering +3) If the function name has "add" in it, the caller is transferring control of the memory to the routine. ( icalproperty_add_parameter() ) 4) If the function name has "remove" in it, the caller passes in @@ -911,42 +1185,44 @@ library. Here is a summary of the memory rules. you do not own "foo" and after the call returns, you do. 5) If the routine returns a string, libical owns the memory and will - put it on a ring buffer to reclaim later. You'd better strdup() - it if you want to keep it, and you don't have to delete it. + put it on a ring buffer to reclaim later. For example, icalcomponent_as_ical_string(). + You'd better strdup() it if you want to keep it, and you don't have + to delete it. -6.6 Error Handling +5.6 Error Handling -Libical has several error handling mechanisms for the varioustypes +Libical has several error handling mechanisms for the various types of programming, semantic and syntactic errors you may encounter. -6.6.1 Return values +5.6.1 Return values Many library routines signal errors through their return values. All routines that return a pointer, such as icalcomponent_new(), will return 0 ( zero ) on a fatal error. Some routines will return a value of enum icalerrorenum. -6.6.2 icalerrno +5.6.2 icalerrno Most routines will set the global error value icalerrno on errors. -This variable is an enumeration; permissable values can be found in +This variable is an enumeration; permissible values can be found in libical/icalerror.h. If the routine returns an enum icalerrorenum, then the return value will be the same as icalerrno. You can use icalerror_strerror() to get a string that describes the error -6.6.3 X-LIC-ERROR and X-LIC-INVALID-COMPONENT +5.6.3 X-LIC-ERROR and X-LIC-INVALID-COMPONENT The library handles semantic and syntactic errors in components by inserting errors properties into the components. If the parser cannot parse incoming text ( a syntactic error ) or if the icalrestriction_check() -routine indicates that the component does not meet the requirments +routine indicates that the component does not meet the requirements of RFC2446 ( a semantic error) the library will insert properties of the type X-LIC-ERROR to describe the error. Here is an example of the error property: X-LIC-ERROR;X-LIC-ERRORTYPE=INVALID_ITIP :Failed iTIP restrictions -for property DTSTART. Expected 1 instances of the property and got -0 +for property DTSTART. + +Expected 1 instances of the property and got 0 This error resulted from a call to icalrestriction_check(), which discovered that the component does not have a DTSTART property, as required by @@ -954,27 +1230,30 @@ RFC2445. There are a few routines to manipulate error properties: -+-------------------------------------+-----------------------------------------------+ -| Routine | Purpose | -+-------------------------------------+-----------------------------------------------+ -| void icalrestriction_check() | Check a component against RFC2446 and insert | -+-------------------------------------+-----------------------------------------------+ -| | error properties to indicate non compliance | -+-------------------------------------+-----------------------------------------------+ -| int icalcomponent_count_errors() | Return the number of error properties | -+-------------------------------------+-----------------------------------------------+ -| | in a component | -+-------------------------------------+-----------------------------------------------+ -| void icalcomponent_strip_errors() | Remove all error properties in as | -+-------------------------------------+-----------------------------------------------+ -| | component | -+-------------------------------------+-----------------------------------------------+ -| void icalcomponent_convert_errors() | Convert some error properties into | -+-------------------------------------+-----------------------------------------------+ -| | REQUESTS-STATUS to indicate the inability to | -+-------------------------------------+-----------------------------------------------+ -| | process the component as an iTIP request. | -+-------------------------------------+-----------------------------------------------+ +[ The following data is supposed to be in a table. It looks OK in LyX, +but does not format propertly in output. ] + ++-------------------------------------+---------------------------------------------------------+ +| Routine | Purpose | ++-------------------------------------+---------------------------------------------------------+ +| void icalrestriction_check() | Check a component against RFC2446 and insert | ++-------------------------------------+---------------------------------------------------------+ +| | error properties to indicate non compliance | ++-------------------------------------+---------------------------------------------------------+ +| int icalcomponent_count_errors() | Return the number of error properties | ++-------------------------------------+---------------------------------------------------------+ +| | in a component | ++-------------------------------------+---------------------------------------------------------+ +| void icalcomponent_strip_errors() | Remove all error properties in as | ++-------------------------------------+---------------------------------------------------------+ +| | component | ++-------------------------------------+---------------------------------------------------------+ +| void icalcomponent_convert_errors() | Convert some error properties into | ++-------------------------------------+---------------------------------------------------------+ +| | REQUESTS-STATUS proprties to indicate the inability to | ++-------------------------------------+---------------------------------------------------------+ +| | process the component as an iTIP request. | ++-------------------------------------+---------------------------------------------------------+ The types of errors are listed in icalerror.h. They are: @@ -1000,12 +1279,12 @@ is generated by icalvcal_convert() when it encounters a vCal property that it cannot convert or does not know about. Icalcomponent_convert_errors() converts some of the error properties -ina component into REQUEST-STATUS properties that indicate a failure. +in a component into REQUEST-STATUS properties that indicate a failure. As of libical version0.18, this routine only convert *PARSEERROR errors and it always generates a 3.x ( failure ) code. This makes it more of a good idea than a really useful bit of code. -6.7 Naming Standard +5.7 Naming Standard Structures that you access with the "struct" keyword, such as "struct icaltimetype" are things that you are allowed to see inside and poke @@ -1030,21 +1309,8 @@ as the second word. For instance: ICAL_ROLE_REQPARTICIPANT or ICAL_PARTSTAT_ACCE The enums for the parts of a recurarance rule and request statuses are irregular. -7 Useful Recipies - -Iteration - -Copying components. Remember that you must clone or remove an object -before putting in on another list. - -Finding compliance errors - -8 Performance - -Checking restrictions is computationally expensive. - -9 Hacks and Bugs +6 Hacks and Bugs There are a lot of hacks in the library -- bits of code that I am not -proud of and should propbably be changed. These are marked with the +proud of and should probably be changed. These are marked with the comment string "HACK." |