Item creation & insertion from JSON

src/Item.zig

@@ -6,7 +6,7 @@ const sqlite = @import("sqlite");
 
 const Self = @This();
 
-pub const Tag = struct{
+pub const Tag = struct {
     // :0 for C compatility
     name: [:0]const u8,
     value: ?[:0]const u8,
@@ -14,12 +14,27 @@ pub const Tag = struct{
 
 id: ?i64, // If null, the object hasn't been persisted
 tags: ?[]Tag,
+allocator: ?std.mem.Allocator = null,
+
+pub fn deinit(self: *Self) void {
+    // If there's no allocator there has been no allocations
+    const allocator = self.allocator orelse return;
+    const tags = self.tags orelse return;
+
+    // Free each tag
+    for (tags) |*tag| {
+        allocator.free(tag.name);
+
+        if (tag.value) |value| {
+            allocator.free(value);
+        }
+    }
+
+    // Free the tags buffer
+    allocator.free(tags);
+}
 
 pub fn persist(self: *Self, db: *sqlite.Db) !void {
-    ///////////////////////////////////
-    // ** Insert item **
-    /////////////////////////////////
-
     // Insert only if there's no ID.
     if (self.id == null) {
         const query = "INSERT INTO item VALUES(NULL);";
@@ -29,44 +44,31 @@ pub fn persist(self: *Self, db: *sqlite.Db) !void {
         self.id = try Db.getLastId(db);
     }
 
-    ///////////////////////////////////
-    // ** Insert tags **
-    /////////////////////////////////
-
     // If the tags haven't been initialized, don't touch anything
     if (self.tags) |tags| {
-        // TODO: Remove unused tag relations
-        //       If the count drops to zero, delete.
-
         // Create new tags if they don't exist
+        // TODO: Do the "if they don't exist" part.
         for (tags) |*tags_i| {
-            try db.exec(
+            const name_query = "INSERT INTO tag (name) VALUES (?)";
-                "INSERT INTO tag (name) VALUES (?);",
+            try db.exec(name_query, .{}, .{ .name = tags_i.name });
-                .{},
+            const rel_query = "INSERT INTO item_tag (item, tag, value) VALUES (?, ?, ?);";
-                .{ .name = tags_i.name }
+            try db.exec(rel_query, .{}, .{ .item = self.id, .tag = tags_i.name, .value = tags_i.value });
-            );
-
-            try db.exec(
-                "INSERT INTO item_tag (item, tag, value) VALUES (?, ?, ?);",
-                .{},
-                .{ .item = self.id, .tag = tags_i.name, .value = tags_i.value }
-            );
         }
     }
-
 }
 
 /// Convert into a JSON object. A call to deinit() is necessary from the caller's side
 pub fn toJson(self: Self) json.Obj {
+    // Main object
     var jobj = json.Obj.newObject();
 
-    jobj.objectAdd("id", &json.Obj.newInt64(self.id.?));
+    // Add id (i64|null)
+    jobj.objectAdd("id", if (self.id) |id| &json.Obj.newInt64(id) else null);
 
     var jtags = json.Obj.newObject();
     jobj.objectAdd("tags", &jtags);
 
-    // If there are tags there's no point on continuing
+    // Add tags only if they're initialized
-
     if (self.tags) |tags| {
         for (tags) |tag_i| {
             const jtag = if (tag_i.value) |value|
@@ -80,3 +82,27 @@ pub fn toJson(self: Self) json.Obj {
 
     return jobj;
 }
+
+pub fn fromJson(jobj: json.Obj, allocator: std.mem.Allocator) !Self {
+    var jtags = jobj.objectGet("tags");
+    defer jtags.deinit();
+
+    const len = @intCast(usize, jtags.objectLen());
+    var tags = try allocator.alloc(Tag, len);
+
+    var iter = jtags.objectGetIterator();
+
+    var i: usize = 0;
+    while (iter.next()) |*tag| {
+        tags[i].name = try allocator.dupeZ(u8, tag.key);
+        tags[i].value = if (tag.value) |*value| try allocator.dupeZ(u8, value.getString()) else null;
+
+        i += 1;
+    }
+
+    return Self{
+        .id = null,
+        .tags = tags,
+        .allocator = allocator,
+    };
+}

src/json.zig

@@ -60,6 +60,10 @@ pub const Obj = struct {
         return Obj{ .obj = c.json_object_get(obj).? };
     }
 
+    pub fn objectLen(self: *const Obj) c_int {
+        return c.json_object_object_length(self.obj);
+    }
+
     pub fn objectGetIterator(self: *Obj) ObjectIterator {
         // TODO: Check errors
         return ObjectIterator{

src/main.zig

@@ -9,15 +9,16 @@ const json = @import("json.zig");
 pub fn main() !void {
     var db = try Db.init();
 
-    //var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
+    var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
-    //defer arena.deinit();
+    defer arena.deinit();
-    //const alloc = arena.allocator();
+    const allocator = arena.allocator();
 
     const jsonText: [:0]const u8 =
         \\{
         \\    "tags": {
-        \\        "title": "clean room",
+        \\        "title": "Programar sistema de TODO",
-        \\        "task": null
+        \\        "programming" : "zig",
+        \\        "due" : "2023-01-01"
         \\    }
         \\}
     ;
@@ -25,25 +26,13 @@ pub fn main() !void {
     var jsonItem = json.Obj.newFromString(jsonText);
     defer jsonItem.deinit();
 
-    _ = db;
+    var item = try Item.fromJson(jsonItem, allocator);
+    defer item.deinit();
 
-    //var item = Item.fromJson(jsonItem);
+    try item.persist(&db);
 
-    //try item.persist(&db);
+    var jobj = item.toJson();
-
-    //var jobj = item.toJson();
-
-    var jobj = jsonItem.objectGet("tags");
     defer jobj.deinit();
 
-    var iter = jobj.objectGetIterator();
+    std.debug.print("{s}\n", .{jobj.toString()});
-    while(iter.next()) |*tag| {
-        std.debug.print("{s}", .{tag.key});
-        defer std.debug.print("\n", .{});
-
-        if (tag.value) |*value| {
-            std.debug.print(" => {s}", .{value.getString()});
-        }
-    }
-
 }