Implement dumping to file

src/dump.c

@@ -1,46 +1,186 @@
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
 #include <jansson.h>
 
-char *json_dumps(const json_t *json, uint32_t flags)
-{
-    (void)flags;
+typedef int (*dump_func)(const char *buffer, int size, void *data);
 
+static int dump_to_file(const char *buffer, int size, void *data)
+{
+    FILE *dest = (FILE *)data;
+    if(fwrite(buffer, size, 1, dest) != 1)
+        return -1;
+    return 0;
+}
+
+static int dump_indent(uint32_t flags, int depth, dump_func dump, void *data)
+{
+    if(JSON_INDENT(flags) > 0)
+    {
+        char *ws_buffer;
+        int ws_count = JSON_INDENT(flags) * depth;
+
+        if(dump("\n", 1, data))
+            return -1;
+
+        if(ws_count == 0)
+            return 0;
+
+        ws_buffer = alloca(ws_count);
+        memset(ws_buffer, ' ', ws_count);
+        return dump(ws_buffer, ws_count, data);
+    }
+    else
+        return dump(" ", 1, data);
+}
+
+static int dump_string(const char *str, dump_func dump, void *data)
+{
+    const char *end;
+
+    if(dump("\"", 1, data))
+        return -1;
+
+    end = str;
+    while(*end)
+    {
+        while(*end && *end != '\\' && *end != '"')
+            end++;
+
+        if(end != str)
+            if(dump(str, end - str, data))
+                return -1;
+
+        if(*end == '\\')
+        {
+            if(dump("\\\\", 2, data))
+                return -1;
+            end++;
+        }
+        else if(*end == '"')
+        {
+            if(dump("\\\"", 2, data))
+                return -1;
+            end++;
+        }
+        str = end;
+    }
+
+    return dump("\"", 1, data);
+}
+
+static int do_dump(const json_t *json, uint32_t flags, int depth,
+                   dump_func dump, void *data)
+{
     switch(json_typeof(json)) {
         case JSON_NULL:
-            printf("null");
-            break;
+            return dump("null", 4, data);
 
         case JSON_TRUE:
-            printf("true");
-            break;
+            return dump("true", 4, data);
 
         case JSON_FALSE:
-            printf("false");
-            break;
+            return dump("false", 5, data);
 
         case JSON_NUMBER:
-            printf("%f", json_number_value(json));
-            break;
+        {
+            char *buffer;
+            int size, ret;
+
+            size = asprintf(&buffer, "%.17f", json_number_value(json));
+            if(size == -1)
+                return -1;
+
+            ret = dump(buffer, size, data);
+            free(buffer);
+            return ret;
+        }
 
         case JSON_STRING:
-            printf("%s", json_string_value(json));
-            break;
+            return dump_string(json_string_value(json), dump, data);
+
+        case JSON_ARRAY:
+        {
+            int i;
+            int n = json_array_size(json);
+
+            if(dump("[", 1, data))
+                return -1;
+            if(n == 0)
+                dump("]", 1, data);
+            if(dump_indent(flags, depth + 1, dump, data))
+                return -1;
 
-        case JSON_ARRAY: {
-            int i, n = json_array_size(json);
-            printf("[");
             for(i = 0; i < n; ++i) {
-                json_dumps(json_array_get(json, i), 0);
+                if(do_dump(json_array_get(json, i), flags, depth + 1,
+                           dump, data))
+                    return -1;
+
                 if(i < n - 1)
-                    printf(", ");
+                {
+                    if(dump(",", 1, data) ||
+                       dump_indent(flags, depth + 1, dump, data))
+                        return -1;
+                }
+                else
+                {
+                    if(dump_indent(flags, depth, dump, data))
+                        return -1;
+                }
             }
-            printf("]");
-            break;
+            return dump("]", 1, data);
+        }
+
+        case JSON_OBJECT:
+        {
+            void *iter = json_object_iter((json_t *)json);
+
+            if(dump("{", 1, data))
+                return -1;
+            if(!iter)
+                return dump("}", 1, data);
+            if(dump_indent(flags, depth + 1, dump, data))
+                return -1;
+
+            while(iter)
+            {
+                void *next = json_object_iter_next((json_t *)json, iter);
+
+                dump_string(json_object_iter_key(iter), dump, data);
+                if(dump(": ", 2, data) ||
+                   do_dump(json_object_iter_value(iter), flags, depth + 1,
+                           dump, data))
+                    return -1;
+
+                if(next)
+                {
+                    if(dump(",", 1, data) ||
+                       dump_indent(flags, depth + 1, dump, data))
+                        return -1;
+                }
+                else
+                {
+                    if(dump_indent(flags, depth, dump, data))
+                        return -1;
+                }
+
+                iter = next;
+            }
+            return dump("}", 1, data);
         }
 
         default:
-            printf("<object>");
-            break;
+            /* not reached */
+            return -1;
     }
-    return NULL;
 }
 
+
+int json_dumpf(const json_t *json, FILE *output, uint32_t flags)
+{
+    if(do_dump(json, flags, 0, dump_to_file, (void *)output))
+        return -1;
+    return dump_to_file("\n", 1, (void *)output);
+}