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The submodule code recently grew generic code to build a
dynamic argv array. Many other parts of the code can reuse
this, too, so let's make it generically available.
There are two enhancements not found in the original code:
1. We now handle the NULL-termination invariant properly,
even when no strings have been pushed (before, you
could have an empty, NULL argv). This was not a problem
for the submodule code, which always pushed at least
one argument, but was not sufficiently safe for
generic code.
2. There is a formatted variant of the "push" function.
This is a convenience function which was not needed by
the submodule code, but will make it easier to port
other users to the new code.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
46 lines
1.6 KiB
Text
46 lines
1.6 KiB
Text
argv-array API
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==============
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The argv-array API allows one to dynamically build and store
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NULL-terminated lists. An argv-array maintains the invariant that the
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`argv` member always points to a non-NULL array, and that the array is
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always NULL-terminated at the element pointed to by `argv[argc]`. This
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makes the result suitable for passing to functions expecting to receive
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argv from main(), or the link:api-run-command.html[run-command API].
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The link:api-string-list.html[string-list API] is similar, but cannot be
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used for these purposes; instead of storing a straight string pointer,
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it contains an item structure with a `util` field that is not compatible
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with the traditional argv interface.
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Each `argv_array` manages its own memory. Any strings pushed into the
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array are duplicated, and all memory is freed by argv_array_clear().
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Data Structures
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---------------
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`struct argv_array`::
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A single array. This should be initialized by assignment from
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`ARGV_ARRAY_INIT`, or by calling `argv_array_init`. The `argv`
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member contains the actual array; the `argc` member contains the
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number of elements in the array, not including the terminating
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NULL.
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Functions
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---------
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`argv_array_init`::
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Initialize an array. This is no different than assigning from
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`ARGV_ARRAY_INIT`.
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`argv_array_push`::
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Push a copy of a string onto the end of the array.
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`argv_array_pushf`::
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Format a string and push it onto the end of the array. This is a
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convenience wrapper combining `strbuf_addf` and `argv_array_push`.
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`argv_array_clear`::
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Free all memory associated with the array and return it to the
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initial, empty state.
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