Potential to break libchewing compatibility when adding new keyboard layout

[mlouielu]

Current keyboard layout enum in bopomofo-private.h is the following:

libchewing/include/internal/bopomofo-private.h

Lines 30 to 45 in 197b701

	enum {
	KB_DEFAULT,
	KB_HSU,
	KB_IBM,
	KB_GIN_YIEH,
	KB_ET,
	KB_ET26,
	KB_DVORAK,
	KB_DVORAK_HSU,
	KB_DACHEN_CP26,
	KB_HANYU_PINYIN,
	KB_THL_PINYIN,
	KB_MPS2_PINYIN,
	KB_CARPALX,
	KB_TYPE_NUM
	};

And some of the code in bopomofo.c use this to distinguish bopomofo and pinyin input method:

libchewing/src/bopomofo.c

Line 667 in 197b701

if (pBopomofo->kbtype >= KB_HANYU_PINYIN) {

It has the potential to break compatibility when adding new keyboard layout (insert before KB_HANYU_PINYIN), which let adding new keyboard layout difficult. It also affect KB_CARPALX which is not a pinyin keyboard.

Adding a new function to distinguish this may be a way to solve this problem.

[kanru]

Good point. It seems current code assumes everything after KB_HANYU_PINYIN is a pinyin keyboard.

[kanru]

On second thought this is not breaking any ABI.

The enum values are part of the API/ABI so they should never change once added. To add new keyboard type, append them to the end of the enum list.

In bopomofo.c we know exactly what kbtype they are. The check at

libchewing/src/bopomofo.c

Line 667 in 197b701

if (pBopomofo->kbtype >= KB_HANYU_PINYIN) {

is a bug.

[mlouielu]

Closed by #441, further new keyboard layout needs to take care of BopomofoKbIsPinyin().