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QUnicodeTools: Use thread-safe libthai API

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Use th_brk_new()/th_brk_find_breaks() instead of non-thread-safe
th_brk(). The new API is available in libthai since version
0.1.25 released on 2016-06-28.

[ChangeLog][QtCore] Correct line wrapping of Thai text now requires
libthai version 0.1.25 or above.

Fixes: QTBUG-105544
Change-Id: I723050bef9f4e6445c946125c74c99e50addadef
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
(cherry picked from commit 19ca03c21c2cf69fdec4dd8d6a03b92eb96314ca)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
This commit is contained in:
Ievgenii Meshcheriakov 2023-01-09 16:04:36 +01:00 committed by Qt Cherry-pick Bot
parent e344e887de
commit ed739a5c42
1 changed files with 21 additions and 5 deletions
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26
src/corelib/text/qunicodetools.cpp
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@ -1402,11 +1402,19 @@ struct thcell_t {
unsigned char hilo; /**< upper/lower vowel/diacritic */
unsigned char top; /**< top-level mark */
};
typedef int (*th_brk_def) (const unsigned char*, int*, size_t);
typedef struct _ThBrk ThBrk;
typedef ThBrk *(*th_brk_new_def)(const char *);
typedef int (*th_brk_find_breaks_def)(ThBrk *, const unsigned char *, int *, size_t);
typedef size_t (*th_next_cell_def) (const unsigned char *, size_t, struct thcell_t *, int);
// Global state for th_brk_find_breaks().
// Note: even if signature for th_brk_find_breaks() suggests otherwise, the
// state is read-only, and so it is safe to use it from multiple threads after
// initialization. This is also stated in the libthai documentation.
Q_CONSTINIT static ThBrk *th_state = nullptr;
/* libthai related function handles */
Q_CONSTINIT static th_brk_def th_brk = nullptr;
Q_CONSTINIT static th_brk_find_breaks_def th_brk_find_breaks = nullptr;
Q_CONSTINIT static th_next_cell_def th_next_cell = nullptr;
static int init_libthai() {
@ -1416,12 +1424,19 @@ static int init_libthai() {
if (!initialized.loadAcquire()) {
const auto locker = std::scoped_lock(mutex);
if (!initialized.loadAcquire()) {
th_brk = reinterpret_cast<th_brk_def>(QLibrary::resolve("thai"_L1, LIBTHAI_MAJOR, "th_brk"));
th_brk_find_breaks = reinterpret_cast<th_brk_find_breaks_def>(
QLibrary::resolve("thai"_L1, LIBTHAI_MAJOR, "th_brk_find_breaks"));
th_next_cell = (th_next_cell_def)QLibrary::resolve("thai"_L1, LIBTHAI_MAJOR, "th_next_cell");
auto th_brk_new = reinterpret_cast<th_brk_new_def>(
QLibrary::resolve("thai"_L1, LIBTHAI_MAJOR, "th_brk_new"));
if (th_brk_new)
th_state = th_brk_new(nullptr);
initialized.storeRelease(true);
}
}
if (th_brk && th_next_cell)
if (th_brk_find_breaks && th_next_cell && th_state)
return 1;
else
#endif
@ -1487,7 +1502,8 @@ static void thaiAssignAttributes(const char16_t *string, qsizetype len, QCharAtt
attributes[0].wordBreak = true;
attributes[0].wordStart = true;
attributes[0].wordEnd = false;
numbreaks = th_brk(reinterpret_cast<const unsigned char *>(cstr), break_positions, brp_size);
numbreaks = th_brk_find_breaks(th_state, reinterpret_cast<const unsigned char *>(cstr),
break_positions, brp_size);
for (i = 0; i < numbreaks; ++i) {
attributes[break_positions[i]].wordBreak = true;
attributes[break_positions[i]].wordStart = true;