doc/manual/helper.txt

   1 /** @page helperdocs OpenOCD Helper APIs
   2
   3 OpenOCD uses several low-level APIs as the foundation for high-level APIs:
   4
   5   - @subpage helperporting
   6   - @subpage helperjim
   7   - @subpage helpercommand
   8   - @subpage helperlogging
   9   - @subpage helperbuffers
  10
  11 This section needs to be expanded.
  12
  13  */
  14
  15 /** @page helperporting OpenOCD Types/Portability APIs
  16
  17 This section needs to be expanded to describe OpenOCD's type and
  18 portability API.
  19
  20  */
  21
  22 /** @page helperjim OpenOCD Jim API
  23
  24 The Jim API provides access to a small-footprint TCL implementation.
  25
  26 Visit http://jim.tcl.tk/ for more information on Jim.
  27
  28 This section needs to be expanded to describe OpenOCD's Jim API.
  29
  30  */
  31
  32 /** @page helpercommand OpenOCD Command API
  33
  34 OpenOCD's command API allows modules to register callbacks that are then
  35 available to the scripting services.  It provides the mechanism for
  36 these commands to be dispatched to the module using a standard
  37 interface.  It provides macros for defining functions that use and
  38 extend this interface.
  39
  40 @section helpercmdhandler Command Handlers
  41
  42 Command handlers are functions with a particular signature, which can
  43 be extended by modules for passing additional parameters to helpers or
  44 another layer of handlers.
  45
  46 @subsection helpercmdhandlerdef Defining and Calling Command Handlers
  47
  48 These functions should be defined using the @c COMMAND_HANDLER macro.
  49 These methods must be defined as static, as their principal entry point
  50 should be the run_command dispatch mechanism.
  51
  52 Command helper functions that require access to the full set of
  53 parameters should be defined using the @c COMMAND_HELPER.  These must be
  54 declared static by you, as sometimes you might want to share a helper
  55 among several files (e.g. @c s3c24xx_nand.h).
  56
  57 Both types of routines must be called using the @c CALL_COMMAND_HANDLER macro.
  58 Calls using this macro to normal handlers require the name of the command
  59 handler (which can be a name or function pointer).  Calls to helpers and
  60 derived handlers must pass those extra parameters specified by their
  61 definitions; however, lexical capture is used for the core parameters.
  62 This dirty trick is being used as a stop-gap measure while the API is
  63 migrated to one that passes a pointer to a structure containing the
  64 same ingredients.  At that point, this macro will be removed and callers
  65 will be able to use direct invocations.
  66
  67 Thus, the following macros can be used to define and call command
  68 handlers or helpers:
  69
  70 - @c COMMAND_HANDLER - declare or define a command handler.
  71 - @c COMMAND_HELPER - declare or define a derived command handler or helper.
  72 - @c CALL_COMMAND_HANDLER - call a command handler/helper.
  73
  74 @subsection helpercmdhandlermacros Command Handler Macros
  75
  76 In addition, the following macros may be used in the context of
  77 command handlers and helpers:
  78 - @c CMD_CTX - the current @c command_context
  79 - @c CMD_NAME - invoked command name
  80 - @c CMD_ARGC - the number of command arguments
  81 - @c CMD_ARGV - array of command argument strings
  82 - @c CMD_JIMTCL_ARGV - array containing the Jim_Obj equivalent of command
  83   argument in @c CMD_ARGV.
  84
  85 @section helpercmdregister Command Registration
  86
  87 In order to use a command handler, it must be registered with the
  88 command subsystem.  All commands are registered with command_registration
  89 structures, specifying the name of the command, its handler, its allowed
  90 mode(s) of execution, and strings that provide usage and help text.
  91 A single handler may be registered using multiple names, but any name
  92 may have only one handler associated with it.
  93
  94 The @c register_command() and @c register_commands() functions provide
  95 registration, while the @c unregister_command() and
  96 @c unregister_all_commands() functions will remove existing commands.
  97 These may be called at any time, allowing the command set to change in
  98 response to system actions.
  99
 100 @subsection helpercmdjim Jim Command Registration
 101
 102 The command_registration structure provides support for registering
 103 native Jim command handlers (@c jim_handler) too.  For these handlers,
 104 the module can provide help and usage support; however, this mechanism
 105 allows Jim handlers to be called as sub-commands of other commands.
 106 These commands may be registered with a private data value (@c
 107 jim_handler_data) that will be available when called, as with low-level
 108 Jim command registration.
 109
 110 A command may have a normal @c handler or a @c jim_handler, but not both.
 111
 112 @subsection helpercmdregisterchains Command Chaining
 113
 114 When using register_commands(), the array of commands may reference
 115 other arrays.  When the @c chain field is filled in a
 116 command_registration record, the commands on in the chained list will
 117 added in one of two places.  If the record defines a new command, then
 118 the chained commands are added under it; otherwise, the commands are
 119 added in the same context as the other commands in the array.
 120
 121 @section helpercmdprimer Command Development Primer
 122
 123 This @ref primercommand provides details about the @c hello module,
 124 showing how the pieces described on this page fit together.
 125
 126  */
 127
 128 /** @page helperlogging OpenOCD Logging API
 129
 130 This section needs to be expanded to describe OpenOCD's Logging API.
 131
 132  */
 133
 134 /** @page helperbuffers OpenOCD Byte Buffer API
 135
 136 This section needs to be expanded to describe OpenOCD's Byte Buffer API.
 137
 138  */