Enum parsing

generator/spec-parse.zig

@@ -5,6 +5,8 @@ const mem = std.mem;
 const Allocator = mem.Allocator;
 const ArenaAllocator = std.heap.ArenaAllocator;
 
+const api_constants_name = "API Constants";
+
 pub const ParseResult = struct {
     arena: ArenaAllocator,
     registry: registry.Registry,
@@ -14,18 +16,17 @@ pub const ParseResult = struct {
     }
 };
 
-pub fn parseXml(allocator: *Allocator, root: *xml.Element) !ParseResult {
-    var arena = ArenaAllocator.init(allocator);
+pub fn parseXml(backing_allocator: *Allocator, root: *xml.Element) !ParseResult {
+    var arena = ArenaAllocator.init(backing_allocator);
     errdefer arena.deinit();
 
-    var reg = registry.Registry{
-        .decls = &[_]registry.Declaration{},
-        .api_constants = &[_]registry.ApiConstant{},
-        .tags = &[_]registry.Tag{},
-    };
+    const allocator = &arena.allocator;
 
-    reg.api_constants = try parseApiConstants(&arena.allocator, root);
-    reg.tags = try parseTags(&arena.allocator, root);
+    var reg = registry.Registry{
+        .decls = try parseDeclarations(allocator, root),
+        .api_constants = try parseApiConstants(allocator, root),
+        .tags = try parseTags(allocator, root),
+    };
 
     return ParseResult{
         .arena = arena,
@@ -33,12 +34,117 @@ pub fn parseXml(allocator: *Allocator, root: *xml.Element) !ParseResult {
     };
 }
 
+fn parseDeclarations(allocator: *Allocator, root: *xml.Element) ![]registry.Declaration {
+    var types_elem = root.findChildByTag("types") orelse return error.InvalidRegistry;
+    var commands_elem = root.findChildByTag("commands") orelse return error.InvalidRegistry;
+
+    const decl_upper_bound = types_elem.children.count() + commands_elem.children.count();
+    const decls = try allocator.alloc(registry.Declaration, decl_upper_bound);
+    errdefer allocator.free(decls);
+
+    var count: usize = 0;
+    count += try parseTypes(allocator, decls, types_elem);
+    count += try parseEnums(allocator, decls[count..], root);
+    count += try parseCommands(allocator, decls[count..], commands_elem);
+    return allocator.shrink(decls, count);
+}
+
+fn parseTypes(allocator: *Allocator, out: []registry.Declaration, types_elem: *xml.Element) !usize {
+    return 0;
+}
+
+fn parseEnums(allocator: *Allocator, out: []registry.Declaration, root: *xml.Element) !usize {
+    var i: usize = 0;
+    var it = root.findChildrenByTag("enums");
+    while (it.next()) |enums| {
+        const name = enums.getAttribute("name") orelse return error.InvalidRegistry;
+        if (mem.eql(u8, name, api_constants_name)) {
+            continue;
+        }
+
+        out[i] = .{
+            .name = name,
+            .decl_type = .{.Enum = try parseEnumFields(allocator, enums)},
+        };
+        i += 1;
+    }
+
+    return i;
+}
+
+fn parseEnumFields(allocator: *Allocator, elem: *xml.Element) !registry.Enum {
+    // TODO: `type` was added recently, fall back to checking endswith FlagBits for older versions?
+    const enum_type = elem.getAttribute("type") orelse return error.InvalidRegistry;
+    const is_bitmask = mem.eql(u8, enum_type, "bitmask");
+    if (!is_bitmask and !mem.eql(u8, enum_type, "enum")) {
+        return error.InvalidRegistry;
+    }
+
+    const fields = try allocator.alloc(registry.Enum.Field, elem.children.count());
+    errdefer allocator.free(fields);
+
+    var i: usize = 0;
+    var it = elem.findChildrenByTag("enum");
+    while (it.next()) |field| {
+        fields[i] = try parseEnumField(field);
+        i += 1;
+    }
+
+    return registry.Enum{
+        .fields = allocator.shrink(fields, i),
+        .is_bitmask = is_bitmask,
+    };
+}
+
+fn parseEnumField(field: *xml.Element) !registry.Enum.Field {
+    const is_compat_alias = if (field.getAttribute("comment")) |comment|
+        mem.eql(u8, comment, "Backwards-compatible alias containing a typo") or
+            mem.eql(u8, comment, "Deprecated name for backwards compatibility")
+    else
+        false;
+
+    const name = field.getAttribute("name") orelse return error.InvalidRegistry;
+    const value: registry.Enum.Value = blk: {
+        // An enum variant's value could be defined by any of the following attributes:
+        // - value: Straight up value of the enum variant, in either base 10 or 16 (prefixed with 0x).
+        // - bitpos: Used for bitmasks, and can also be set in extensions.
+        // - alias: The field is an alias of another variant within the same enum.
+        // - offset: Used with features and extensions, where a non-bitpos value is added to an enum.
+        //     The value is given by `1e9 + (extr_nr - 1) * 1e3 + offset`, where `ext_nr` is either
+        //     given by the `extnumber` field (in the case of a feature), or given in the parent <extension>
+        //     tag. In the latter case its passed via the `ext_nr` parameter.
+        // TODO: Handle `offset` elsewhere
+        if (field.getAttribute("value")) |value| {
+            if (mem.startsWith(u8, value, "0x")) {
+                break :blk .{.bit_vector = try std.fmt.parseInt(i32, value[2..], 16)};
+            } else {
+                break :blk .{.int = try std.fmt.parseInt(i32, value, 10)};
+            }
+        } else if (field.getAttribute("bitpos")) |bitpos| {
+            break :blk .{.bitpos = try std.fmt.parseInt(u5, bitpos, 10)};
+        } else if (field.getAttribute("alias")) |alias| {
+            break :blk .{.alias = .{.alias_name = alias, .is_compat_alias = is_compat_alias}};
+        } else {
+            return error.InvalidRegistry;
+        }
+    };
+
+    return registry.Enum.Field{
+        .name = name,
+        .value = value,
+    };
+}
+
+fn parseCommands(allocator: *Allocator, out: []registry.Declaration, commmands_elem: *xml.Element) !usize {
+    return 0;
+}
+
 fn parseApiConstants(allocator: *Allocator, root: *xml.Element) ![]registry.ApiConstant {
     var enums = blk: {
-        var it = root.elements();
+        var it = root.findChildrenByTag("enums");
         while (it.next()) |child| {
             const name = child.getAttribute("name") orelse continue;
-            if (mem.eql(u8, name, "API Constants")) {
+            if (mem.eql(u8, name, api_constants_name)) {
                 break :blk child;
             }
         }
@@ -46,7 +152,7 @@ fn parseApiConstants(allocator: *Allocator, root: *xml.Element) ![]registry.ApiC
         return error.InvalidRegistry;
     };
 
-    var constants = try allocator.alloc(registry.ApiConstant, enums.children.count());
+    const constants = try allocator.alloc(registry.ApiConstant, enums.children.count());
     errdefer allocator.free(constants);
 
     var i: usize = 0;
@@ -72,7 +178,7 @@ fn parseApiConstants(allocator: *Allocator, root: *xml.Element) ![]registry.ApiC
 
 fn parseTags(allocator: *Allocator, root: *xml.Element) ![]registry.Tag {
     var tags_elem = root.findChildByTag("tags") orelse return error.InvalidRegistry;
-    var tags = try allocator.alloc(registry.Tag, tags_elem.children.count());
+    const tags = try allocator.alloc(registry.Tag, tags_elem.children.count());
     errdefer allocator.free(tags);
 
     var i: usize = 0;