LVar: put now can throw an error

Author: cyberglot

kklib/include/kklib.h

@@ -2,7 +2,7 @@
 #ifndef KKLIB_H
 #define KKLIB_H
 
-#define KKLIB_BUILD        91     // modify on changes to trigger recompilation
+#define KKLIB_BUILD        95     // modify on changes to trigger recompilation
 #define KK_MULTI_THREADED   1       // set to 0 to be used single threaded only
 // #define KK_DEBUG_FULL       1
 

kklib/include/kklib/thread.h

@@ -1,4 +1,5 @@
 #pragma once
+#include <sys/_types/_int32_t.h>
 #ifndef KK_THREAD_H
 #define KK_THREAD_H
 /*---------------------------------------------------------------------------
@@ -32,7 +33,7 @@ kk_decl_export kk_promise_t kk_task_schedule_n( kk_ssize_t count, kk_ssize_t str
 typedef kk_box_t kk_lvar_t;
 
 kk_decl_export kk_lvar_t kk_lvar_alloc(kk_box_t lattice_bottom, kk_context_t *ctx);
-kk_decl_export void      kk_lvar_put(kk_lvar_t lvar, kk_function_t update, kk_context_t *ctx);
+kk_decl_export int32_t   kk_lvar_put(kk_lvar_t lvar, kk_function_t update, kk_context_t *ctx);
 kk_decl_export kk_box_t  kk_lvar_get( kk_lvar_t lvar, kk_function_t in_threshold_set, kk_context_t* ctx );
 kk_decl_export kk_box_t  kk_lvar_freeze(kk_lvar_t lvar, kk_context_t *ctx);
 

kklib/src/thread.c

@@ -493,7 +493,7 @@ typedef struct lvar_s {
 typedef kk_box_t kk_lvar_t;
 
 kk_lvar_t kk_lvar_alloc( kk_box_t lattice_bottom, kk_context_t* ctx );
-void      kk_lvar_put(kk_lvar_t lvar, kk_function_t update, kk_context_t *ctx);
+int32_t   kk_lvar_put(kk_lvar_t lvar, kk_function_t update, kk_context_t *ctx);
 kk_box_t  kk_lvar_get( kk_lvar_t lvar, kk_function_t in_threshold_set, kk_context_t* ctx );
 kk_box_t  kk_lvar_freeze(kk_lvar_t lvar, kk_context_t *ctx);
 
@@ -528,34 +528,41 @@ kk_lvar_t kk_lvar_alloc(kk_box_t lattice_bottom, kk_context_t* ctx) {
 }
 
 // add value to lvar
-void kk_lvar_put(kk_lvar_t lvar, kk_function_t update, kk_context_t *ctx) {
+// int32 boolean flag for error
+int32_t kk_lvar_put(kk_lvar_t lvar, kk_function_t update, kk_context_t *ctx) {
   lvar_t *lv = (lvar_t *)kk_cptr_raw_unbox(lvar);
+  kk_box_t result;
 
   if (lv->is_frozen != 0) goto err;
 
   pthread_mutex_lock(&lv->lock);
-  lv->result =
+  result = lv->result;
+  // add some dup stuff I don't understand
+  result =
     kk_function_call(kk_box_t, (kk_function_t, kk_box_t, kk_context_t *),
-                     update, (update, lv->result, ctx));
+                     update, (update, result, ctx));
 
-  kk_box_mark_shared(lv->result, ctx); // TODO: can we mark outside the mutex?
+  kk_box_mark_shared(result, ctx); // TODO: can we mark outside the mutex?
 
   // null means that update went to top
-  if (kk_box_is_null(lv->result)) goto err;
+  if (kk_box_is_null(result)) {
+    pthread_mutex_unlock(&lv->lock);
+    goto err;
+  }
 
+  lv->result = result;
+  // drop stuff here?
   pthread_mutex_unlock(&lv->lock);
-
   pthread_cond_broadcast(&lv->available);
 
   kk_box_drop(lvar, ctx);
   kk_function_drop(update, ctx);
-  return;
+  return 1;
 
 err:
-  // TODO: how to throw an error?
   kk_box_drop(lvar, ctx);
   kk_function_drop(update, ctx);
-  return;
+  return 0;
 }
 
 static void kk_lvar_wait (kk_lvar_t lvar, kk_context_t* ctx) {

lib/std/os/lvar.kk

@@ -24,23 +24,23 @@ abstract struct lvar<a> {
   compare : (a, a) -> maybe<order>;
 }
 
-noinline extern unsafe-lvar( bottom : a ) : pure any {
+noinline extern unsafe-lvar( bottom : a ) : total any {
   c "kk_lvar_alloc"
 }
 
-noinline extern unsafe-put( lv : any, update : a -> null<a>) : pure () {
+noinline extern unsafe-put( lv : any, update : a -> null<a>) : total int32 {
   c "kk_lvar_put"
 }
 
-noinline extern unsafe-get( lv : any, in-threshold-set : (a, int32) -> null<a> ) : pure a {
+noinline extern unsafe-get( lv : any, in-threshold-set : (a, int32) -> null<a> ) : total a {
   c "kk_lvar_get"
 }
 
-noinline extern unsafe-freeze( lv : any ) : pure a {
+noinline extern unsafe-freeze( lv : any ) : total a {
   c "kk_lvar_freeze"
 }
 
-public noinline fun lvar( bottom : a, join : (a, a) -> maybe<a>, compare : (a, a) -> maybe<order>) : pure lvar<a> {
+public noinline fun lvar( bottom : a, join : (a, a) -> maybe<a>, compare : (a, a) -> maybe<order>) : total lvar<a> {
   Lvar( unsafe-lvar(bottom), join, compare )
 }
 
@@ -49,8 +49,11 @@ public noinline fun lvar( bottom : a, join : (a, a) -> maybe<a>, compare : (a, a
 //   d <= update(d)                             -- monotonicity
 //   update1(update2(d)) == update2(update1(d)) -- commutativity
 //
-public fun put( lvar : lvar<a>, update : a -> maybe<a> ) : pure () {
-  lvar.lv.unsafe-put( fn (d) { d.update.null } )
+public fun put( lvar : lvar<a>, update : a -> maybe<a> ) : exn () {
+  match (lvar.lv.unsafe-put( fn (d) { d.update.null } ).bool) {
+    True -> ()
+    False -> throw("LVar was frozen when `put` was attempted")
+  }
 }
 
 public fun put( lvar : lvar<a>, d : a ) : pure () {