library: meminfo redesigned to use 'stack' vs. 'chain'

In addition to that text shown below the line which is
common to several commit messages, this patch contains
the following additional change without an API impact:

. The #include header files are ordered alphabetically
now, with all those <sys/??> types separately grouped.

------------------------------------------------------
. The former 'chains' have now become 'stacks' without
the 'next' pointer in each result struct. The pointers
initially seemed to offer some flexibility with memory
allocations and benefits for the library access logic.
However, user access was always via displacement and a
a statically allocated chain was cumbersome to define.

. An enumerator ending in '_noop' will no longer serve
as a fencepost delimiter. Rather, it has become a much
more important and flexible user oriented tool. Adding
one or more such 'items' in any items list passed into
the library becomes the means of extending the 'stack'
to also include user (not just library) data. Any such
data is guaranteed to never be altered by the library.

. Anticipating PID support, where many different types
must be represented in a result structure, we'll adopt
a common naming standard. And, while not every results
structure currently needs to reflect disparate types a
union will be employed so the same dot qualifier ('.')
can be used consistently when accessing all such data.

Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit is contained in:
Jim Warner
2015-07-21 00:00:00 -05:00
committed by Craig Small
parent 887f2a81d7
commit b8c688fb36
4 changed files with 161 additions and 144 deletions

View File

@@ -28,36 +28,38 @@
__BEGIN_DECLS
enum meminfo_item {
PROCPS_MEMHI_FREE,
PROCPS_MEMHI_TOTAL,
PROCPS_MEMHI_USED,
PROCPS_MEMLO_FREE,
PROCPS_MEMLO_TOTAL,
PROCPS_MEMLO_USED,
PROCPS_MEM_ACTIVE,
PROCPS_MEM_AVAILABLE,
PROCPS_MEM_BUFFERS,
PROCPS_MEM_CACHED,
PROCPS_MEM_FREE,
PROCPS_MEM_INACTIVE,
PROCPS_MEM_SHARED,
PROCPS_MEM_TOTAL,
PROCPS_MEM_USED,
PROCPS_SWAP_FREE,
PROCPS_SWAP_TOTAL,
PROCPS_SWAP_USED,
PROCPS_MEM_noop
PROCPS_MEMHI_FREE, // ul_int
PROCPS_MEMHI_TOTAL, // ul_int
PROCPS_MEMHI_USED, // ul_int
PROCPS_MEMLO_FREE, // ul_int
PROCPS_MEMLO_TOTAL, // ul_int
PROCPS_MEMLO_USED, // ul_int
PROCPS_MEM_ACTIVE, // ul_int
PROCPS_MEM_AVAILABLE, // ul_int
PROCPS_MEM_BUFFERS, // ul_int
PROCPS_MEM_CACHED, // ul_int
PROCPS_MEM_FREE, // ul_int
PROCPS_MEM_INACTIVE, // ul_int
PROCPS_MEM_SHARED, // ul_int
PROCPS_MEM_TOTAL, // ul_int
PROCPS_MEM_USED, // ul_int
PROCPS_SWAP_FREE, // ul_int
PROCPS_SWAP_TOTAL, // ul_int
PROCPS_SWAP_USED, // ul_int
PROCPS_MEM_noop, // n/a
PROCPS_MEM_stack_end // n/a
};
struct procps_meminfo;
struct meminfo_result {
enum meminfo_item item;
unsigned long result;
struct meminfo_result *next;
union {
unsigned long ul_int;
} result;
};
struct meminfo_chain {
struct meminfo_stack {
struct meminfo_result *head;
};
@@ -72,15 +74,15 @@ unsigned long procps_meminfo_get (
struct procps_meminfo *info,
enum meminfo_item item);
int procps_meminfo_getchain (
int procps_meminfo_getstack (
struct procps_meminfo *info,
struct meminfo_result *these);
int procps_meminfo_chain_fill (
int procps_meminfo_stack_fill (
struct procps_meminfo *info,
struct meminfo_chain *chain);
struct meminfo_stack *stack);
struct meminfo_chain *procps_meminfo_chain_alloc (
struct meminfo_stack *procps_meminfo_stack_alloc (
struct procps_meminfo *info,
int maxitems,
enum meminfo_item *items);