Use pthread TLD to store contexts

Author: wtlangford

configure.ac

@@ -135,17 +135,9 @@ AC_CHECK_MEMBER([struct tm.tm_gmtoff], [AC_DEFINE([HAVE_TM_TM_GMT_OFF],1,[Define
 AC_CHECK_MEMBER([struct tm.__tm_gmtoff], [AC_DEFINE([HAVE_TM___TM_GMT_OFF],1,[Define to 1 if the system has the __tm_gmt_off field in struct tm])],
                 [], [[#include <time.h>]])
 
-AC_ARG_ENABLE([pthread-tls],
-              [AC_HELP_STRING([--enable-pthread-tls],
-                              [Enable use of pthread thread local storage])],
-              [],
-              [enable_pthread_tls=no])
-
-if test $enable_pthread_tls = yes; then
-    AC_FIND_FUNC([pthread_key_create], [pthread], [#include <pthread.h>], [NULL, NULL])
-    AC_FIND_FUNC([pthread_once], [pthread], [#include <pthread.h>], [NULL, NULL])
-    AC_FIND_FUNC([atexit], [pthread], [#include <stdlib.h>], [NULL])
-fi
+AC_FIND_FUNC([pthread_key_create], [pthread], [#include <pthread.h>], [NULL, NULL])
+AC_FIND_FUNC([pthread_once], [pthread], [#include <pthread.h>], [NULL, NULL])
+AC_FIND_FUNC([atexit], [pthread], [#include <stdlib.h>], [NULL])
 
 dnl libm math.h functions
 AC_CHECK_MATH_FUNC(acos)

src/jv_type_number.c

@@ -52,6 +52,94 @@ static decContext dec_context = {
   0, /*no clamping*/
 };
 
+static decContext dec_context_to_double = {
+  BIN64_DEC_PRECISION,
+  DEC_MAX_EMAX,
+  DEC_MIN_EMAX,
+  DEC_ROUND_HALF_UP,
+  0, /*no errors*/
+  0, /*status*/
+  0, /*no clamping*/
+};
+
+#include <pthread.h>
+
+static pthread_key_t dec_ctx_key;
+static pthread_key_t dec_ctx_dbl_key;
+static pthread_once_t dec_ctx_once = PTHREAD_ONCE_INIT;
+
+#define DEC_CONTEXT tsd_dec_ctx_get(&dec_ctx_key)
+#define DEC_CONTEXT_TO_DOUBLE tsd_dec_ctx_get(&dec_ctx_dbl_key)
+
+static void tsd_dec_ctx_init() {
+  if (pthread_key_create(&dec_ctx_key, jv_mem_free) != 0) {
+    fprintf(stderr, "error: cannot create thread specific key");
+    abort();
+  }
+  decContext *ctx = calloc(1, sizeof(decContext));
+  *ctx = dec_context;
+  if (pthread_setspecific(dec_ctx_key, ctx) != 0) {
+    fprintf(stderr, "error: cannot set thread specific data");
+    abort();
+  }
+
+  if (pthread_key_create(&dec_ctx_dbl_key, jv_mem_free) != 0) {
+    fprintf(stderr, "error: cannot create thread specific key");
+    abort();
+  }
+  ctx = calloc(1, sizeof(decContext));
+  *ctx = dec_context_to_double;
+  if (pthread_setspecific(dec_ctx_dbl_key, ctx) != 0) {
+    fprintf(stderr, "error: cannot set thread specific data");
+    abort();
+  }
+}
+
+static decContext* tsd_dec_ctx_get(pthread_key_t *key) {
+  pthread_once(&dec_ctx_once, tsd_dec_ctx_init); // cannot fail
+  return (decContext*)pthread_getspecific(*key);
+}
+
+
+static pthread_key_t dtoa_ctx_key;
+static pthread_once_t dtoa_ctx_once = PTHREAD_ONCE_INIT;
+
+static struct dtoa_context *tsd_dtoa_context();
+
+static void tsd_dtoa_ctx_dtor(void *ptr) {
+  if (ptr) {
+    jvp_dtoa_context_free((struct dtoa_context*)ptr);
+    jv_mem_free(ptr);
+  }
+}
+static void tsd_dtoa_ctx_fini() {
+  struct dtoa_context *ctx = tsd_dtoa_context();
+  tsd_dtoa_ctx_dtor(ctx);
+  pthread_setspecific(dtoa_ctx_key, NULL);
+}
+
+static void tsd_dtoa_ctx_init() {
+    if (pthread_key_create(&dtoa_ctx_key, tsd_dtoa_ctx_fini) != 0) {
+    fprintf(stderr, "error: cannot create thread specific key");
+    abort();
+  }
+  atexit(tsd_dtoa_ctx_fini);
+}
+
+static inline struct dtoa_context *tsd_dtoa_context() {
+  pthread_once(&dtoa_ctx_once, tsd_dtoa_ctx_init); // cannot fail
+  struct dtoa_context *ctx = (struct dtoa_context*)pthread_getspecific(dtoa_ctx_key);
+  if (!ctx) {
+    ctx = malloc(sizeof(struct dtoa_context));
+    jvp_dtoa_context_init(ctx);
+    if (pthread_setspecific(dtoa_ctx_key, ctx) != 0) {
+      fprintf(stderr, "error: cannot set thread specific data");
+      abort();
+    }
+  }
+  return ctx;
+}
+
 typedef struct {
   jv_refcnt refcnt;
   double num_double;
@@ -69,34 +157,6 @@ typedef struct {
   decNumberUnit units[BIN64_DEC_PRECISION];
 } decNumberDoublePrecision;
 
-static decContext dec_context_to_double = {
-  BIN64_DEC_PRECISION,
-  DEC_MAX_EMAX,
-  DEC_MIN_EMAX,
-  DEC_ROUND_HALF_UP,
-  0, /*no errors*/
-  0, /*status*/
-  0, /*no clamping*/
-};
-
-static struct {
-  uint64_t refcnt;
-  struct dtoa_context C;
-} shared_dtoa_context;
-
-static void jvp_number_dtoa_ctx_require() {
-  if (shared_dtoa_context.refcnt == 0) {
-    jvp_dtoa_context_init(&shared_dtoa_context.C);
-  }
-  shared_dtoa_context.refcnt ++;
-}
-
-static void jvp_number_dtoa_ctx_release() {
-  assert(shared_dtoa_context.refcnt > 0);
-  if (--shared_dtoa_context.refcnt == 0) {
-    jvp_dtoa_context_free(&shared_dtoa_context.C);
-  }
-}
 
 static inline int jvp_number_is_literal(jv n) {
   assert(JVP_HAS_KIND(n, JV_KIND_NUMBER));
@@ -130,15 +190,12 @@ static jv jvp_literal_number_new(const char * literal) {
 
   jvp_literal_number * n = jvp_literal_number_alloc(strlen(literal));
 
-  // make sure that the dtoa context is somewhere around
-  jvp_number_dtoa_ctx_require();
-
   n->refcnt = JV_REFCNT_INIT;
   n->literal_data = NULL;
-  decNumberFromString(&n->num_decimal, literal, &dec_context);
+  decNumberFromString(&n->num_decimal, literal, DEC_CONTEXT);
   n->num_double = NAN;
 
-  if (dec_context.status & DEC_Conversion_syntax) {
+  if (DEC_CONTEXT->status & DEC_Conversion_syntax) {
     jv_mem_free(n);
     return JV_INVALID;
   }
@@ -157,12 +214,12 @@ static double jvp_literal_number_to_double(jv j) {
   // reduce the number to the shortest possible form
   // while also making sure than no more than BIN64_DEC_PRECISION 
   // digits are used (dec_context_to_double)
-  decNumberReduce(&dec_double.number, p_dec_number, &dec_context_to_double);
+  decNumberReduce(&dec_double.number, p_dec_number, DEC_CONTEXT_TO_DOUBLE);
 
   decNumberToString(&dec_double.number, literal);
 
   char *end;
-  return jvp_strtod(&shared_dtoa_context.C, literal, &end);
+  return jvp_strtod(tsd_dtoa_context(), literal, &end);
 }
 
 
@@ -219,7 +276,6 @@ const char* jv_number_get_literal(jv n) {
 void jvp_number_free(jv j) {
   assert(JVP_HAS_KIND(j, JV_KIND_NUMBER));
   if (JVP_HAS_FLAGS(j, JVP_FLAGS_NUMBER_LITERAL) && jvp_refcnt_dec(j.u.ptr)) {
-    jvp_number_dtoa_ctx_release();
     jvp_literal_number* n = jvp_literal_number_ptr(j);
     if (n->literal_data) {
       jv_mem_free(n->literal_data);
@@ -286,7 +342,7 @@ int jvp_number_cmp(jv a, jv b) {
     decNumberCompare(&res.number, 
                      jvp_dec_number_ptr(a), 
                      jvp_dec_number_ptr(b),
-                     &dec_context
+                     DEC_CONTEXT
                      );
     if (decNumberIsZero(&res.number)) {
       return 0;