Move from Jansson to JV - proper freeing of memory

A few more tests, now passes valgrind.

c/builtin.c

@@ -1,15 +1,18 @@
 #include "builtin.h"
 
 static void f_false(jv input[], jv output[]) {
+  jv_free(input[0]);
   output[0] = jv_false();
 }
 
 static void f_true(jv input[], jv output[]) {
+  jv_free(input[0]);
   output[0] = jv_true();
 }
 
 
 static void f_plus(jv input[], jv output[]) {
+  jv_free(input[0]);
   jv a = input[2];
   jv b = input[1];
   if (jv_get_kind(a) == JV_KIND_NUMBER && jv_get_kind(b) == JV_KIND_NUMBER) {
@@ -19,6 +22,8 @@ static void f_plus(jv input[], jv output[]) {
     output[0] = jv_array_concat(a, b);
   } else {
     output[0] = jv_string("wtf gaize");
+    jv_free(a);
+    jv_free(b);
   }
 }
 

c/execute.c

@@ -24,6 +24,7 @@ int pathsize; // number of allocated elements
 
 // FIXME mem
 int path_push(stackval sv, jv val) {
+  return 0;
   int pos = sv.pathidx;
   assert(pos <= pathsize);
   assert(pos >= 0);
@@ -54,17 +55,18 @@ typedef struct {
   stackval sv;
 } data_stk_elem;
 
-void stk_push(stackval val) {
+void stack_push(stackval val) {
   data_stk_elem* s = forkable_stack_push(&data_stk, sizeof(data_stk_elem));
   s->sv = val;
 }
 
-stackval stk_pop() {
+stackval stack_pop() {
   data_stk_elem* s = forkable_stack_peek(&data_stk);
   stackval sv = s->sv;
-  if (!forkable_stack_pop(&data_stk)) {
+  if (!forkable_stack_pop_will_free(&data_stk)) {
     sv.value = jv_copy(sv.value);
   }
+  forkable_stack_pop(&data_stk);
   return sv;
 }
 
@@ -92,6 +94,14 @@ void stack_switch() {
 }
 
 void stack_restore(){
+  while (!forkable_stack_empty(&data_stk) && 
+         forkable_stack_pop_will_free(&data_stk)) {
+    jv_free(stack_pop().value);
+  }
+  while (!forkable_stack_empty(&frame_stk) && 
+         forkable_stack_pop_will_free(&frame_stk)) {
+    frame_pop(&frame_stk);
+  }
   struct forkpoint* fork = forkable_stack_peek(&fork_stk);
   forkable_stack_restore(&data_stk, &fork->saved_data_stack);
   forkable_stack_restore(&frame_stk, &fork->saved_call_stack);
@@ -114,9 +124,6 @@ static struct closure make_closure(struct forkable_stack* stk, frame_ptr fr, uin
 }
 
 
-#define stack_push stk_push
-#define stack_pop stk_pop
-
 #define ON_BACKTRACK(op) ((op)+NUM_OPCODES)
 
 jv jq_next() {
@@ -142,10 +149,12 @@ jv jq_next() {
       if (i == 0) {
         param = forkable_stack_peek(&data_stk);
       } else {
+        printf(" | ");
         param = forkable_stack_peek_next(&data_stk, param);
       }
+      if (!param) break;
       jv_dump(jv_copy(param->sv.value));
-      if (i < opdesc->stack_in-1) printf(" | ");
+      printf("<%d>", jv_get_refcnt(param->sv.value));
     }
 
     if (backtracking) {
@@ -294,6 +303,7 @@ jv jq_next() {
       int idx = jv_number_value(stack_pop().value);
       stackval array = stack_pop();
       if (idx >= jv_array_length(jv_copy(array.value))) {
+        jv_free(array.value);
         goto do_backtrack;
       } else {
         stack_save();
@@ -314,7 +324,7 @@ jv jq_next() {
     do_backtrack:
     case BACKTRACK: {
       if (forkable_stack_empty(&fork_stk)) {
-        // FIXME: invalid
+        // FIXME: invalid jv value
         return jv_null();
       }
       stack_restore();
@@ -407,6 +417,7 @@ void jq_init(struct bytecode* bc, jv input) {
   forkable_stack_init(&data_stk, sizeof(stackval) * 1000); // FIXME: lower this number, see if it breaks
   forkable_stack_init(&frame_stk, 10240); // FIXME: lower this number, see if it breaks
   forkable_stack_init(&fork_stk, 10240); // FIXME: lower this number, see if it breaks
+  stack_save();
   
   stack_push(stackval_root(input));
   struct closure top = {bc, -1};
@@ -414,6 +425,18 @@ void jq_init(struct bytecode* bc, jv input) {
   frame_push_backtrack(&frame_stk, bc->code);
 }
 
+void jq_teardown() {
+  while (!forkable_stack_empty(&fork_stk)) {
+    stack_restore();
+  }
+  assert(forkable_stack_empty(&fork_stk));
+  assert(forkable_stack_empty(&data_stk));
+  assert(forkable_stack_empty(&frame_stk));
+  forkable_stack_free(&fork_stk);
+  forkable_stack_free(&data_stk);
+  forkable_stack_free(&frame_stk);
+}
+
 void run_program(struct bytecode* bc) {
   char buf[4096];
   fgets(buf, sizeof(buf), stdin);

c/forkable_stack.h

@@ -46,6 +46,13 @@ static void forkable_stack_init(struct forkable_stack* s, size_t sz) {
   forkable_stack_check(s);
 }
 
+static void forkable_stack_free(struct forkable_stack* s) {
+  assert(forkable_stack_empty(s));
+  assert(s->savedlimit == s->length);
+  free(s->stk);
+  s->stk = 0;
+}
+
 static void* forkable_stack_push(struct forkable_stack* s, size_t size) {
   forkable_stack_check(s);
   int curr = s->pos < s->savedlimit ? s->pos : s->savedlimit;
@@ -83,14 +90,16 @@ static void* forkable_stack_peek_next(struct forkable_stack* s, void* top) {
   }
 }
 
-// Returns 1 if the object being popped can not be accessed again
-// (i.e. was not saved with a fork)
-static int forkable_stack_pop(struct forkable_stack* s) {
+// Returns 1 if the next forkable_stack_pop will permanently remove an
+// object from the stack (i.e. the top object was not saved with a fork)
+static int forkable_stack_pop_will_free(struct forkable_stack* s) {
+  return s->pos < s->savedlimit ? 1 : 0;
+}
+
+static void forkable_stack_pop(struct forkable_stack* s) {
   forkable_stack_check(s);
-  int finalpop = s->pos < s->savedlimit ? 1 : 0;
   struct forkable_stack_header* elem = forkable_stack_peek(s);
   s->pos = elem->next;
-  return finalpop;
 }
 
 
@@ -114,12 +123,14 @@ static void forkable_stack_switch(struct forkable_stack* s, struct forkable_stac
 
   int curr_limit = s->savedlimit;
   if (curr_pos < curr_limit) s->savedlimit = curr_pos;
-  state->prevlimit = curr_limit;
+  //state->prevlimit = curr_limit; FIXME clean up
   forkable_stack_check(s);
 }
 
 static void forkable_stack_restore(struct forkable_stack* s, struct forkable_stack_state* state) {
   forkable_stack_check(s);
+  assert(s->savedlimit <= state->prevpos);
+  assert(s->savedlimit <= state->prevlimit);
   s->pos = state->prevpos;
   s->savedlimit = state->prevlimit;
   forkable_stack_check(s);

c/frame_layout.h

@@ -11,6 +11,8 @@ struct continuation {
   struct bytecode* bc;
   stack_idx env;
   uint16_t* retaddr;
+  // FIXME: probably not necessary as a separate field
+  int is_backtrack_frame;
 };
 
 typedef union frame_elem {
@@ -84,6 +86,7 @@ static frame_ptr frame_push(struct forkable_stack* stk, struct closure cl, uint1
   cc->bc = cl.bc;
   cc->env = cl.env;
   cc->retaddr = retaddr;
+  cc->is_backtrack_frame = 0;
   for (int i=0; i<cl.bc->nlocals; i++) {
     *frame_local_var(fp, i) = jv_null();
   }
@@ -93,12 +96,22 @@ static frame_ptr frame_push(struct forkable_stack* stk, struct closure cl, uint1
 static frame_ptr frame_push_backtrack(struct forkable_stack* stk, uint16_t* retaddr) {
   struct continuation cc = *frame_self(frame_current(stk));
   frame_ptr fp = forkable_stack_push(stk, sizeof(union frame_elem) * 2);
+  assert(!cc.is_backtrack_frame);
+  cc.is_backtrack_frame = 1;
   cc.retaddr = retaddr;
   *frame_self(fp) = cc;
   return fp;
 }
 
 static void frame_pop(struct forkable_stack* stk) {
+  frame_ptr fp = frame_current(stk);
+  if (forkable_stack_pop_will_free(stk) && 
+      !frame_self(fp)->is_backtrack_frame) {
+    int nlocals = frame_self(fp)->bc->nlocals;
+    for (int i=0; i<nlocals; i++) {
+      jv_free(*frame_local_var(fp, i));
+    }
+  }
   forkable_stack_pop(stk);
 }
 

c/jv.c

@@ -2,6 +2,7 @@
 #include <stddef.h>
 #include <assert.h>
 #include <stdlib.h>
+#include <stdio.h>
 #include <string.h>
 
 #include "jv.h"
@@ -641,6 +642,21 @@ static int jvp_object_length(jv_complex* object) {
   return n;
 }
 
+static int jvp_object_equal(jv_complex* o1, jv_complex* o2) {
+  int len2 = jvp_object_length(o2);
+  int len1 = 0;
+  for (int i=0; i<jvp_object_size(o1); i++) {
+    struct object_slot* slot = jvp_object_get_slot(o1, i);
+    if (!slot->string) continue;
+    jv* slot2 = jvp_object_read(o2, slot->string);
+    if (!slot2) return 0;
+    // FIXME: do less refcounting here
+    if (!jv_equal(jv_copy(slot->value), jv_copy(*slot2))) return 0;
+    len1++;
+  }
+  return len1 == len2;
+}
+
 /*
  * Objects (public interface)
  */
@@ -752,6 +768,17 @@ void jv_free(jv j) {
   }
 }
 
+int jv_get_refcnt(jv j) {
+  switch (jv_get_kind(j)) {
+  case JV_KIND_ARRAY:
+  case JV_KIND_STRING:
+  case JV_KIND_OBJECT:
+    return j.val.complex.ptr->count;
+  default:
+    return 1;
+  }
+}
+
 /*
  * Higher-level operations
  */
@@ -772,7 +799,11 @@ int jv_equal(jv a, jv b) {
     case JV_KIND_STRING: {
       r = jvp_string_equal(&a.val.complex, &b.val.complex);
       break;
-    }    
+    }
+    case JV_KIND_OBJECT: {
+      r = jvp_object_equal(&a.val.complex, &b.val.complex);
+      break;
+    }
     default:
       r = 1;
       break;

c/jv.h

@@ -82,6 +82,8 @@ jv jv_object_iter_key(jv, int);
 jv jv_object_iter_value(jv, int);
 
 
+int jv_get_refcnt(jv);
+
 void jv_dump(jv);
 jv jv_parse(const char* string);
 

c/main.c

@@ -8,6 +8,7 @@ block compile(const char* str);
 
 void jq_init(struct bytecode* bc, jv value);
 jv jq_next();
+void jq_teardown();
 
 void run_program(struct bytecode* bc);
 
@@ -67,6 +68,7 @@ void run_tests() {
         pass = 0;
         }*/
     }
+    jq_teardown();
     bytecode_free(bc);
     tests++;
     passed+=pass;

c/testdata

@@ -76,6 +76,27 @@ null
 2
 3
 
+1,1
+[]
+1
+1
+
+[.]
+[2]
+[[2]]
+
+[[2]]
+[3]
+[[2]]
+
+[{}]
+[2]
+[{}]
+
+[.[]]
+["a"]
+["a"]
+
 [(.,1),((.,.[]),(2,3))]
 ["a","b"]
 [["a","b"],1,["a","b"],"a","b",2,3]
@@ -118,7 +139,7 @@ null
 
 1+1
 null
-2.0
+2
 
 .+4
 15
@@ -143,11 +164,17 @@ def f: (1000,2000); f
 1000
 2000
 
-# test backtracking through function calls and returns
-# this test is *evil*
-[[20,10][1,0] as $x | def f: (100,200) as $y | def g: [$x + $y, .]; . + $x | g; f[0] | [f][0][1] | f]
-"woo, testing!"
-[[110.0, 130.0], [210.0, 130.0], [110.0, 230.0], [210.0, 230.0], [120.0, 160.0], [220.0, 160.0], [120.0, 260.0], [220.0, 260.0]]
+([1,2] + [4,5])
+[1,2,3]
+[1,2,4,5]
+
+true
+[1]
+true
+
+[1,2,3]
+[5,6]
+[1,2,3]
 
 def f(x): x | x; f([.], . + [42])
 [1,2,3]
@@ -160,3 +187,9 @@ def f(x): x | x; f([.], . + [42])
 def id(x):x; 2000 as $x | def f(x):1 as $x | id([$x, x, x]); def g(x): 100 as $x | f($x,$x+x); g($x)
 "more testing"
 [1,100,2100.0,100,2100.0]
+
+# test backtracking through function calls and returns
+# this test is *evil*
+[[20,10][1,0] as $x | def f: (100,200) as $y | def g: [$x + $y, .]; . + $x | g; f[0] | [f][0][1] | f]
+"woo, testing!"
+[[110.0, 130.0], [210.0, 130.0], [110.0, 230.0], [210.0, 230.0], [120.0, 160.0], [220.0, 160.0], [120.0, 260.0], [220.0, 260.0]]