struct Stringify [src]
Alias for std.json.Stringify
Writes JSON (RFC8259) formatted data
to a stream.
The sequence of method calls to write JSON content must follow this grammar:
=
=
|
|
| write
| print
|
= beginObject ( )* endObject
= objectField | objectFieldRaw |
= beginArray ( )* endArray
= beginWriteRaw ( stream.writeAll )* endWriteRaw
= beginObjectFieldRaw ( stream.writeAll )* endObjectFieldRaw
Fields writer: *Writer
options: Options = .{}
indent_level: usize = 0
next_punctuation: enum {
the_beginning,
none,
comma,
colon,
} = .the_beginning
nesting_stack: switch (safety_checks) {
.checked_to_fixed_depth => |fixed_buffer_size| [(fixed_buffer_size + 7) >> 3]u8,
.assumed_correct => void,
} = switch (safety_checks) {
.checked_to_fixed_depth => @splat(0),
.assumed_correct => {},
}
raw_streaming_mode: if (build_mode_has_safety)
enum { none, value, objectField }
else
void = if (build_mode_has_safety) .none else {}
Source //! Writes JSON ([RFC8259](https://tools.ietf.org/html/rfc8259)) formatted data
//! to a stream.
//!
//! The sequence of method calls to write JSON content must follow this grammar:
//! ```
//! =
//! =
//! |
//! |
//! | write
//! | print
//! |
//! = beginObject ( )* endObject
//! = objectField | objectFieldRaw |
//! = beginArray ( )* endArray
//! = beginWriteRaw ( stream.writeAll )* endWriteRaw
//! = beginObjectFieldRaw ( stream.writeAll )* endObjectFieldRaw
//! ```
const std = @import("../std.zig");
const assert = std.debug.assert;
const Allocator = std.mem.Allocator;
const ArrayList = std.ArrayList;
const BitStack = std.BitStack;
const Stringify = @This();
const Writer = std.Io.Writer;
const IndentationMode = enum(u1) {
object = 0,
array = 1,
};
writer: *Writer,
options: Options = .{},
indent_level: usize = 0,
next_punctuation: enum {
the_beginning,
none,
comma,
colon,
} = .the_beginning,
nesting_stack: switch (safety_checks) {
.checked_to_fixed_depth => |fixed_buffer_size| [(fixed_buffer_size + 7) >> 3]u8,
.assumed_correct => void,
} = switch (safety_checks) {
.checked_to_fixed_depth => @splat(0),
.assumed_correct => {},
},
raw_streaming_mode: if (build_mode_has_safety)
enum { none, value, objectField }
else
void = if (build_mode_has_safety) .none else {},
const build_mode_has_safety = switch (@import("builtin").mode) {
.Debug, .ReleaseSafe => true,
.ReleaseFast, .ReleaseSmall => false,
};
/// The `safety_checks_hint` parameter determines how much memory is used to enable assertions that the above grammar is being followed,
/// e.g. tripping an assertion rather than allowing `endObject` to emit the final `}` in `[[[]]}`.
/// "Depth" in this context means the depth of nested `[]` or `{}` expressions
/// (or equivalently the amount of recursion on the `` grammar expression above).
/// For example, emitting the JSON `[[[]]]` requires a depth of 3.
/// If `.checked_to_fixed_depth` is used, there is additionally an assertion that the nesting depth never exceeds the given limit.
/// `.checked_to_fixed_depth` embeds the storage required in the `Stringify` struct.
/// `.assumed_correct` requires no space and performs none of these assertions.
/// In `ReleaseFast` and `ReleaseSmall` mode, the given `safety_checks_hint` is ignored and is always treated as `.assumed_correct`.
const safety_checks_hint: union(enum) {
/// Rounded up to the nearest multiple of 8.
checked_to_fixed_depth: usize,
assumed_correct,
} = .{ .checked_to_fixed_depth = 256 };
const safety_checks: @TypeOf(safety_checks_hint) = if (build_mode_has_safety)
safety_checks_hint
else
.assumed_correct;
pub const Error = Writer.Error;
pub fn beginArray(self: *Stringify) Error!void {
if (build_mode_has_safety) assert(self.raw_streaming_mode == .none);
try self.valueStart();
try self.writer.writeByte('[');
try self.pushIndentation(.array);
self.next_punctuation = .none;
}
pub fn beginObject(self: *Stringify) Error!void {
if (build_mode_has_safety) assert(self.raw_streaming_mode == .none);
try self.valueStart();
try self.writer.writeByte('{');
try self.pushIndentation(.object);
self.next_punctuation = .none;
}
pub fn endArray(self: *Stringify) Error!void {
if (build_mode_has_safety) assert(self.raw_streaming_mode == .none);
self.popIndentation(.array);
switch (self.next_punctuation) {
.none => {},
.comma => {
try self.indent();
},
.the_beginning, .colon => unreachable,
}
try self.writer.writeByte(']');
self.valueDone();
}
pub fn endObject(self: *Stringify) Error!void {
if (build_mode_has_safety) assert(self.raw_streaming_mode == .none);
self.popIndentation(.object);
switch (self.next_punctuation) {
.none => {},
.comma => {
try self.indent();
},
.the_beginning, .colon => unreachable,
}
try self.writer.writeByte('}');
self.valueDone();
}
fn pushIndentation(self: *Stringify, mode: IndentationMode) !void {
switch (safety_checks) {
.checked_to_fixed_depth => {
BitStack.pushWithStateAssumeCapacity(&self.nesting_stack, &self.indent_level, @intFromEnum(mode));
},
.assumed_correct => {
self.indent_level += 1;
},
}
}
fn popIndentation(self: *Stringify, expected_mode: IndentationMode) void {
switch (safety_checks) {
.checked_to_fixed_depth => {
assert(BitStack.popWithState(&self.nesting_stack, &self.indent_level) == @intFromEnum(expected_mode));
},
.assumed_correct => {
self.indent_level -= 1;
},
}
}
fn indent(self: *Stringify) !void {
var char: u8 = ' ';
const n_chars = switch (self.options.whitespace) {
.minified => return,
.indent_1 => 1 * self.indent_level,
.indent_2 => 2 * self.indent_level,
.indent_3 => 3 * self.indent_level,
.indent_4 => 4 * self.indent_level,
.indent_8 => 8 * self.indent_level,
.indent_tab => blk: {
char = '\t';
break :blk self.indent_level;
},
};
try self.writer.writeByte('\n');
try self.writer.splatByteAll(char, n_chars);
}
fn valueStart(self: *Stringify) !void {
if (self.isObjectKeyExpected()) |is_it| assert(!is_it); // Call objectField*(), not write(), for object keys.
return self.valueStartAssumeTypeOk();
}
fn objectFieldStart(self: *Stringify) !void {
if (self.isObjectKeyExpected()) |is_it| assert(is_it); // Expected write(), not objectField*().
return self.valueStartAssumeTypeOk();
}
fn valueStartAssumeTypeOk(self: *Stringify) !void {
assert(!self.isComplete()); // JSON document already complete.
switch (self.next_punctuation) {
.the_beginning => {
// No indentation for the very beginning.
},
.none => {
// First item in a container.
try self.indent();
},
.comma => {
// Subsequent item in a container.
try self.writer.writeByte(',');
try self.indent();
},
.colon => {
try self.writer.writeByte(':');
if (self.options.whitespace != .minified) {
try self.writer.writeByte(' ');
}
},
}
}
fn valueDone(self: *Stringify) void {
self.next_punctuation = .comma;
}
// Only when safety is enabled:
fn isObjectKeyExpected(self: *const Stringify) ?bool {
switch (safety_checks) {
.checked_to_fixed_depth => return self.indent_level > 0 and
BitStack.peekWithState(&self.nesting_stack, self.indent_level) == @intFromEnum(IndentationMode.object) and
self.next_punctuation != .colon,
.assumed_correct => return null,
}
}
fn isComplete(self: *const Stringify) bool {
return self.indent_level == 0 and self.next_punctuation == .comma;
}
/// An alternative to calling `write` that formats a value with `std.fmt`.
/// This function does the usual punctuation and indentation formatting
/// assuming the resulting formatted string represents a single complete value;
/// e.g. `"1"`, `"[]"`, `"[1,2]"`, not `"1,2"`.
/// This function may be useful for doing your own number formatting.
pub fn print(self: *Stringify, comptime fmt: []const u8, args: anytype) Error!void {
if (build_mode_has_safety) assert(self.raw_streaming_mode == .none);
try self.valueStart();
try self.writer.print(fmt, args);
self.valueDone();
}
test print {
var out_buf: [1024]u8 = undefined;
var out: Writer = .fixed(&out_buf);
var w: Stringify = .{ .writer = &out, .options = .{ .whitespace = .indent_2 } };
try w.beginObject();
try w.objectField("a");
try w.print("[ ]", .{});
try w.objectField("b");
try w.beginArray();
try w.print("[{s}] ", .{"[]"});
try w.print(" {}", .{12345});
try w.endArray();
try w.endObject();
const expected =
\\{
\\ "a": [ ],
\\ "b": [
\\ [[]] ,
\\ 12345
\\ ]
\\}
;
try std.testing.expectEqualStrings(expected, out.buffered());
}
/// An alternative to calling `write` that allows you to write directly to the `.writer` field, e.g. with `.writer.writeAll()`.
/// Call `beginWriteRaw()`, then write a complete value (including any quotes if necessary) directly to the `.writer` field,
/// then call `endWriteRaw()`.
/// This can be useful for streaming very long strings into the output without needing it all buffered in memory.
pub fn beginWriteRaw(self: *Stringify) !void {
if (build_mode_has_safety) {
assert(self.raw_streaming_mode == .none);
self.raw_streaming_mode = .value;
}
try self.valueStart();
}
/// See `beginWriteRaw`.
pub fn endWriteRaw(self: *Stringify) void {
if (build_mode_has_safety) {
assert(self.raw_streaming_mode == .value);
self.raw_streaming_mode = .none;
}
self.valueDone();
}
/// See `Stringify` for when to call this method.
/// `key` is the string content of the property name.
/// Surrounding quotes will be added and any special characters will be escaped.
/// See also `objectFieldRaw`.
pub fn objectField(self: *Stringify, key: []const u8) Error!void {
if (build_mode_has_safety) assert(self.raw_streaming_mode == .none);
try self.objectFieldStart();
try encodeJsonString(key, self.options, self.writer);
self.next_punctuation = .colon;
}
/// See `Stringify` for when to call this method.
/// `quoted_key` is the complete bytes of the key including quotes and any necessary escape sequences.
/// A few assertions are performed on the given value to ensure that the caller of this function understands the API contract.
/// See also `objectField`.
pub fn objectFieldRaw(self: *Stringify, quoted_key: []const u8) Error!void {
if (build_mode_has_safety) assert(self.raw_streaming_mode == .none);
assert(quoted_key.len >= 2 and quoted_key[0] == '"' and quoted_key[quoted_key.len - 1] == '"'); // quoted_key should be "quoted".
try self.objectFieldStart();
try self.writer.writeAll(quoted_key);
self.next_punctuation = .colon;
}
/// In the rare case that you need to write very long object field names,
/// this is an alternative to `objectField` and `objectFieldRaw` that allows you to write directly to the `.writer` field
/// similar to `beginWriteRaw`.
/// Call `endObjectFieldRaw()` when you're done.
pub fn beginObjectFieldRaw(self: *Stringify) !void {
if (build_mode_has_safety) {
assert(self.raw_streaming_mode == .none);
self.raw_streaming_mode = .objectField;
}
try self.objectFieldStart();
}
/// See `beginObjectFieldRaw`.
pub fn endObjectFieldRaw(self: *Stringify) void {
if (build_mode_has_safety) {
assert(self.raw_streaming_mode == .objectField);
self.raw_streaming_mode = .none;
}
self.next_punctuation = .colon;
}
/// Renders the given Zig value as JSON.
///
/// Supported types:
/// * Zig `bool` -> JSON `true` or `false`.
/// * Zig `?T` -> `null` or the rendering of `T`.
/// * Zig `i32`, `u64`, etc. -> JSON number or string.
/// * When option `emit_nonportable_numbers_as_strings` is true, if the value is outside the range `+-1<<53` (the precise integer range of f64), it is rendered as a JSON string in base 10. Otherwise, it is rendered as JSON number.
/// * Zig floats -> JSON number or string.
/// * If the value cannot be precisely represented by an f64, it is rendered as a JSON string. Otherwise, it is rendered as JSON number.
/// * TODO: Float rendering will likely change in the future, e.g. to remove the unnecessary "e+00".
/// * Zig `[]const u8`, `[]u8`, `*[N]u8`, `@Vector(N, u8)`, and similar -> JSON string.
/// * See `Options.emit_strings_as_arrays`.
/// * If the content is not valid UTF-8, rendered as an array of numbers instead.
/// * Zig `[]T`, `[N]T`, `*[N]T`, `@Vector(N, T)`, and similar -> JSON array of the rendering of each item.
/// * Zig tuple -> JSON array of the rendering of each item.
/// * Zig `struct` -> JSON object with each field in declaration order.
/// * If the struct declares a method `pub fn jsonStringify(self: *@This(), jw: anytype) !void`, it is called to do the serialization instead of the default behavior. The given `jw` is a pointer to this `Stringify`. See `std.json.Value` for an example.
/// * See `Options.emit_null_optional_fields`.
/// * Zig `union(enum)` -> JSON object with one field named for the active tag and a value representing the payload.
/// * If the payload is `void`, then the emitted value is `{}`.
/// * If the union declares a method `pub fn jsonStringify(self: *@This(), jw: anytype) !void`, it is called to do the serialization instead of the default behavior. The given `jw` is a pointer to this `Stringify`.
/// * Zig `enum` -> JSON string naming the active tag.
/// * If the enum declares a method `pub fn jsonStringify(self: *@This(), jw: anytype) !void`, it is called to do the serialization instead of the default behavior. The given `jw` is a pointer to this `Stringify`.
/// * If the enum is non-exhaustive, unnamed values are rendered as integers.
/// * Zig untyped enum literal -> JSON string naming the active tag.
/// * Zig error -> JSON string naming the error.
/// * Zig `*T` -> the rendering of `T`. Note there is no guard against circular-reference infinite recursion.
///
/// See also alternative functions `print` and `beginWriteRaw`.
/// For writing object field names, use `objectField` instead.
pub fn write(self: *Stringify, v: anytype) Error!void {
if (build_mode_has_safety) assert(self.raw_streaming_mode == .none);
const T = @TypeOf(v);
switch (@typeInfo(T)) {
.int => {
try self.valueStart();
if (self.options.emit_nonportable_numbers_as_strings and
(v <= -(1 << 53) or v >= (1 << 53)))
{
try self.writer.print("\"{}\"", .{v});
} else {
try self.writer.print("{}", .{v});
}
self.valueDone();
return;
},
.comptime_int => {
return self.write(@as(std.math.IntFittingRange(v, v), v));
},
.float, .comptime_float => {
if (@as(f64, @floatCast(v)) == v) {
try self.valueStart();
try self.writer.print("{}", .{@as(f64, @floatCast(v))});
self.valueDone();
return;
}
try self.valueStart();
try self.writer.print("\"{}\"", .{v});
self.valueDone();
return;
},
.bool => {
try self.valueStart();
try self.writer.writeAll(if (v) "true" else "false");
self.valueDone();
return;
},
.null => {
try self.valueStart();
try self.writer.writeAll("null");
self.valueDone();
return;
},
.optional => {
if (v) |payload| {
return try self.write(payload);
} else {
return try self.write(null);
}
},
.@"enum" => |enum_info| {
if (std.meta.hasFn(T, "jsonStringify")) {
return v.jsonStringify(self);
}
if (!enum_info.is_exhaustive) {
inline for (enum_info.fields) |field| {
if (v == @field(T, field.name)) {
break;
}
} else {
return self.write(@intFromEnum(v));
}
}
return self.stringValue(@tagName(v));
},
.enum_literal => {
return self.stringValue(@tagName(v));
},
.@"union" => {
if (std.meta.hasFn(T, "jsonStringify")) {
return v.jsonStringify(self);
}
const info = @typeInfo(T).@"union";
if (info.tag_type) |UnionTagType| {
try self.beginObject();
inline for (info.fields) |u_field| {
if (v == @field(UnionTagType, u_field.name)) {
try self.objectField(u_field.name);
if (u_field.type == void) {
// void v is {}
try self.beginObject();
try self.endObject();
} else {
try self.write(@field(v, u_field.name));
}
break;
}
} else {
unreachable; // No active tag?
}
try self.endObject();
return;
} else {
@compileError("Unable to stringify untagged union '" ++ @typeName(T) ++ "'");
}
},
.@"struct" => |S| {
if (std.meta.hasFn(T, "jsonStringify")) {
return v.jsonStringify(self);
}
if (S.is_tuple) {
try self.beginArray();
} else {
try self.beginObject();
}
inline for (S.fields) |Field| {
// don't include void fields
if (Field.type == void) continue;
var emit_field = true;
// don't include optional fields that are null when emit_null_optional_fields is set to false
if (@typeInfo(Field.type) == .optional) {
if (self.options.emit_null_optional_fields == false) {
if (@field(v, Field.name) == null) {
emit_field = false;
}
}
}
if (emit_field) {
if (!S.is_tuple) {
try self.objectField(Field.name);
}
try self.write(@field(v, Field.name));
}
}
if (S.is_tuple) {
try self.endArray();
} else {
try self.endObject();
}
return;
},
.error_set => return self.stringValue(@errorName(v)),
.pointer => |ptr_info| switch (ptr_info.size) {
.one => switch (@typeInfo(ptr_info.child)) {
.array => {
// Coerce `*[N]T` to `[]const T`.
const Slice = []const std.meta.Elem(ptr_info.child);
return self.write(@as(Slice, v));
},
else => {
return self.write(v.*);
},
},
.many, .slice => {
if (ptr_info.size == .many and ptr_info.sentinel() == null)
@compileError("unable to stringify type '" ++ @typeName(T) ++ "' without sentinel");
const slice = if (ptr_info.size == .many) std.mem.span(v) else v;
if (ptr_info.child == u8) {
// This is a []const u8, or some similar Zig string.
if (!self.options.emit_strings_as_arrays and std.unicode.utf8ValidateSlice(slice)) {
return self.stringValue(slice);
}
}
try self.beginArray();
for (slice) |x| {
try self.write(x);
}
try self.endArray();
return;
},
else => @compileError("Unable to stringify type '" ++ @typeName(T) ++ "'"),
},
.array => {
// Coerce `[N]T` to `*const [N]T` (and then to `[]const T`).
return self.write(&v);
},
.vector => |info| {
const array: [info.len]info.child = v;
return self.write(&array);
},
else => @compileError("Unable to stringify type '" ++ @typeName(T) ++ "'"),
}
unreachable;
}
fn stringValue(self: *Stringify, s: []const u8) !void {
try self.valueStart();
try encodeJsonString(s, self.options, self.writer);
self.valueDone();
}
pub const Options = struct {
/// Controls the whitespace emitted.
/// The default `.minified` is a compact encoding with no whitespace between tokens.
/// Any setting other than `.minified` will use newlines, indentation, and a space after each ':'.
/// `.indent_1` means 1 space for each indentation level, `.indent_2` means 2 spaces, etc.
/// `.indent_tab` uses a tab for each indentation level.
whitespace: enum {
minified,
indent_1,
indent_2,
indent_3,
indent_4,
indent_8,
indent_tab,
} = .minified,
/// Should optional fields with null value be written?
emit_null_optional_fields: bool = true,
/// Arrays/slices of u8 are typically encoded as JSON strings.
/// This option emits them as arrays of numbers instead.
/// Does not affect calls to `objectField*()`.
emit_strings_as_arrays: bool = false,
/// Should unicode characters be escaped in strings?
escape_unicode: bool = false,
/// When true, renders numbers outside the range `+-1<<53` (the precise integer range of f64) as JSON strings in base 10.
emit_nonportable_numbers_as_strings: bool = false,
};
/// Writes the given value to the `Writer` writer.
/// See `Stringify` for how the given value is serialized into JSON.
/// The maximum nesting depth of the output JSON document is 256.
pub fn value(v: anytype, options: Options, writer: *Writer) Error!void {
var s: Stringify = .{ .writer = writer, .options = options };
try s.write(v);
}
test value {
var out: Writer.Allocating = .init(std.testing.allocator);
const writer = &out.writer;
defer out.deinit();
const T = struct { a: i32, b: []const u8 };
try value(T{ .a = 123, .b = "xy" }, .{}, writer);
try std.testing.expectEqualSlices(u8, "{\"a\":123,\"b\":\"xy\"}", out.written());
try testStringify("9999999999999999", 9999999999999999, .{});
try testStringify("\"9999999999999999\"", 9999999999999999, .{ .emit_nonportable_numbers_as_strings = true });
try testStringify("[1,1]", @as(@Vector(2, u32), @splat(1)), .{});
try testStringify("\"AA\"", @as(@Vector(2, u8), @splat('A')), .{});
try testStringify("[65,65]", @as(@Vector(2, u8), @splat('A')), .{ .emit_strings_as_arrays = true });
// void field
try testStringify("{\"foo\":42}", struct {
foo: u32,
bar: void = {},
}{ .foo = 42 }, .{});
const Tuple = struct { []const u8, usize };
try testStringify("[\"foo\",42]", Tuple{ "foo", 42 }, .{});
comptime {
testStringify("false", false, .{}) catch unreachable;
const MyStruct = struct { foo: u32 };
testStringify("[{\"foo\":42},{\"foo\":100},{\"foo\":1000}]", [_]MyStruct{
MyStruct{ .foo = 42 },
MyStruct{ .foo = 100 },
MyStruct{ .foo = 1000 },
}, .{}) catch unreachable;
}
}
/// Calls `value` and stores the result in dynamically allocated memory instead
/// of taking a writer.
///
/// Caller owns returned memory.
pub fn valueAlloc(gpa: Allocator, v: anytype, options: Options) error{OutOfMemory}![]u8 {
var aw: Writer.Allocating = .init(gpa);
defer aw.deinit();
value(v, options, &aw.writer) catch return error.OutOfMemory;
return aw.toOwnedSlice();
}
test valueAlloc {
const allocator = std.testing.allocator;
const expected =
\\{"foo":"bar","answer":42,"my_friend":"sammy"}
;
const actual = try valueAlloc(allocator, .{ .foo = "bar", .answer = 42, .my_friend = "sammy" }, .{});
defer allocator.free(actual);
try std.testing.expectEqualStrings(expected, actual);
}
fn outputUnicodeEscape(codepoint: u21, w: *Writer) Error!void {
if (codepoint <= 0xFFFF) {
// If the character is in the Basic Multilingual Plane (U+0000 through U+FFFF),
// then it may be represented as a six-character sequence: a reverse solidus, followed
// by the lowercase letter u, followed by four hexadecimal digits that encode the character's code point.
try w.writeAll("\\u");
try w.printInt(codepoint, 16, .lower, .{ .width = 4, .fill = '0' });
} else {
assert(codepoint <= 0x10FFFF);
// To escape an extended character that is not in the Basic Multilingual Plane,
// the character is represented as a 12-character sequence, encoding the UTF-16 surrogate pair.
const high = @as(u16, @intCast((codepoint - 0x10000) >> 10)) + 0xD800;
const low = @as(u16, @intCast(codepoint & 0x3FF)) + 0xDC00;
try w.writeAll("\\u");
try w.printInt(high, 16, .lower, .{ .width = 4, .fill = '0' });
try w.writeAll("\\u");
try w.printInt(low, 16, .lower, .{ .width = 4, .fill = '0' });
}
}
fn outputSpecialEscape(c: u8, writer: *Writer) Error!void {
switch (c) {
'\\' => try writer.writeAll("\\\\"),
'\"' => try writer.writeAll("\\\""),
0x08 => try writer.writeAll("\\b"),
0x0C => try writer.writeAll("\\f"),
'\n' => try writer.writeAll("\\n"),
'\r' => try writer.writeAll("\\r"),
'\t' => try writer.writeAll("\\t"),
else => try outputUnicodeEscape(c, writer),
}
}
/// Write `string` to `writer` as a JSON encoded string.
pub fn encodeJsonString(string: []const u8, options: Options, writer: *Writer) Error!void {
try writer.writeByte('\"');
try encodeJsonStringChars(string, options, writer);
try writer.writeByte('\"');
}
/// Write `chars` to `writer` as JSON encoded string characters.
pub fn encodeJsonStringChars(chars: []const u8, options: Options, writer: *Writer) Error!void {
var write_cursor: usize = 0;
var i: usize = 0;
if (options.escape_unicode) {
while (i < chars.len) : (i += 1) {
switch (chars[i]) {
// normal ascii character
0x20...0x21, 0x23...0x5B, 0x5D...0x7E => {},
0x00...0x1F, '\\', '\"' => {
// Always must escape these.
try writer.writeAll(chars[write_cursor..i]);
try outputSpecialEscape(chars[i], writer);
write_cursor = i + 1;
},
0x7F...0xFF => {
try writer.writeAll(chars[write_cursor..i]);
const ulen = std.unicode.utf8ByteSequenceLength(chars[i]) catch unreachable;
const codepoint = std.unicode.utf8Decode(chars[i..][0..ulen]) catch unreachable;
try outputUnicodeEscape(codepoint, writer);
i += ulen - 1;
write_cursor = i + 1;
},
}
}
} else {
while (i < chars.len) : (i += 1) {
switch (chars[i]) {
// normal bytes
0x20...0x21, 0x23...0x5B, 0x5D...0xFF => {},
0x00...0x1F, '\\', '\"' => {
// Always must escape these.
try writer.writeAll(chars[write_cursor..i]);
try outputSpecialEscape(chars[i], writer);
write_cursor = i + 1;
},
}
}
}
try writer.writeAll(chars[write_cursor..chars.len]);
}
test "json write stream" {
var out_buf: [1024]u8 = undefined;
var out: Writer = .fixed(&out_buf);
var w: Stringify = .{ .writer = &out, .options = .{ .whitespace = .indent_2 } };
try testBasicWriteStream(&w);
}
fn testBasicWriteStream(w: *Stringify) !void {
w.writer.end = 0;
try w.beginObject();
try w.objectField("object");
var arena_allocator = std.heap.ArenaAllocator.init(std.testing.allocator);
defer arena_allocator.deinit();
try w.write(try getJsonObject(arena_allocator.allocator()));
try w.objectFieldRaw("\"string\"");
try w.write("This is a string");
try w.objectField("array");
try w.beginArray();
try w.write("Another string");
try w.write(@as(i32, 1));
try w.write(@as(f32, 3.5));
try w.endArray();
try w.objectField("int");
try w.write(@as(i32, 10));
try w.objectField("float");
try w.write(@as(f32, 3.5));
try w.endObject();
const expected =
\\{
\\ "object": {
\\ "one": 1,
\\ "two": 2
\\ },
\\ "string": "This is a string",
\\ "array": [
\\ "Another string",
\\ 1,
\\ 3.5
\\ ],
\\ "int": 10,
\\ "float": 3.5
\\}
;
try std.testing.expectEqualStrings(expected, w.writer.buffered());
}
fn getJsonObject(allocator: std.mem.Allocator) !std.json.Value {
var v: std.json.Value = .{ .object = std.json.ObjectMap.init(allocator) };
try v.object.put("one", std.json.Value{ .integer = @as(i64, @intCast(1)) });
try v.object.put("two", std.json.Value{ .float = 2.0 });
return v;
}
test "stringify null optional fields" {
const MyStruct = struct {
optional: ?[]const u8 = null,
required: []const u8 = "something",
another_optional: ?[]const u8 = null,
another_required: []const u8 = "something else",
};
try testStringify(
\\{"optional":null,"required":"something","another_optional":null,"another_required":"something else"}
,
MyStruct{},
.{},
);
try testStringify(
\\{"required":"something","another_required":"something else"}
,
MyStruct{},
.{ .emit_null_optional_fields = false },
);
}
test "stringify basic types" {
try testStringify("false", false, .{});
try testStringify("true", true, .{});
try testStringify("null", @as(?u8, null), .{});
try testStringify("null", @as(?*u32, null), .{});
try testStringify("42", 42, .{});
try testStringify("42", 42.0, .{});
try testStringify("42", @as(u8, 42), .{});
try testStringify("42", @as(u128, 42), .{});
try testStringify("9999999999999999", 9999999999999999, .{});
try testStringify("42", @as(f32, 42), .{});
try testStringify("42", @as(f64, 42), .{});
try testStringify("\"ItBroke\"", @as(anyerror, error.ItBroke), .{});
try testStringify("\"ItBroke\"", error.ItBroke, .{});
}
test "stringify string" {
try testStringify("\"hello\"", "hello", .{});
try testStringify("\"with\\nescapes\\r\"", "with\nescapes\r", .{});
try testStringify("\"with\\nescapes\\r\"", "with\nescapes\r", .{ .escape_unicode = true });
try testStringify("\"with unicode\\u0001\"", "with unicode\u{1}", .{});
try testStringify("\"with unicode\\u0001\"", "with unicode\u{1}", .{ .escape_unicode = true });
try testStringify("\"with unicode\u{80}\"", "with unicode\u{80}", .{});
try testStringify("\"with unicode\\u0080\"", "with unicode\u{80}", .{ .escape_unicode = true });
try testStringify("\"with unicode\u{FF}\"", "with unicode\u{FF}", .{});
try testStringify("\"with unicode\\u00ff\"", "with unicode\u{FF}", .{ .escape_unicode = true });
try testStringify("\"with unicode\u{100}\"", "with unicode\u{100}", .{});
try testStringify("\"with unicode\\u0100\"", "with unicode\u{100}", .{ .escape_unicode = true });
try testStringify("\"with unicode\u{800}\"", "with unicode\u{800}", .{});
try testStringify("\"with unicode\\u0800\"", "with unicode\u{800}", .{ .escape_unicode = true });
try testStringify("\"with unicode\u{8000}\"", "with unicode\u{8000}", .{});
try testStringify("\"with unicode\\u8000\"", "with unicode\u{8000}", .{ .escape_unicode = true });
try testStringify("\"with unicode\u{D799}\"", "with unicode\u{D799}", .{});
try testStringify("\"with unicode\\ud799\"", "with unicode\u{D799}", .{ .escape_unicode = true });
try testStringify("\"with unicode\u{10000}\"", "with unicode\u{10000}", .{});
try testStringify("\"with unicode\\ud800\\udc00\"", "with unicode\u{10000}", .{ .escape_unicode = true });
try testStringify("\"with unicode\u{10FFFF}\"", "with unicode\u{10FFFF}", .{});
try testStringify("\"with unicode\\udbff\\udfff\"", "with unicode\u{10FFFF}", .{ .escape_unicode = true });
}
test "stringify many-item sentinel-terminated string" {
try testStringify("\"hello\"", @as([*:0]const u8, "hello"), .{});
try testStringify("\"with\\nescapes\\r\"", @as([*:0]const u8, "with\nescapes\r"), .{ .escape_unicode = true });
try testStringify("\"with unicode\\u0001\"", @as([*:0]const u8, "with unicode\u{1}"), .{ .escape_unicode = true });
}
test "stringify enums" {
const E = enum {
foo,
bar,
};
try testStringify("\"foo\"", E.foo, .{});
try testStringify("\"bar\"", E.bar, .{});
}
test "stringify non-exhaustive enum" {
const E = enum(u8) {
foo = 0,
_,
};
try testStringify("\"foo\"", E.foo, .{});
try testStringify("1", @as(E, @enumFromInt(1)), .{});
}
test "stringify enum literals" {
try testStringify("\"foo\"", .foo, .{});
try testStringify("\"bar\"", .bar, .{});
}
test "stringify tagged unions" {
const T = union(enum) {
nothing,
foo: u32,
bar: bool,
};
try testStringify("{\"nothing\":{}}", T{ .nothing = {} }, .{});
try testStringify("{\"foo\":42}", T{ .foo = 42 }, .{});
try testStringify("{\"bar\":true}", T{ .bar = true }, .{});
}
test "stringify struct" {
try testStringify("{\"foo\":42}", struct {
foo: u32,
}{ .foo = 42 }, .{});
}
test "emit_strings_as_arrays" {
// Should only affect string values, not object keys.
try testStringify("{\"foo\":\"bar\"}", .{ .foo = "bar" }, .{});
try testStringify("{\"foo\":[98,97,114]}", .{ .foo = "bar" }, .{ .emit_strings_as_arrays = true });
// Should *not* affect these types:
try testStringify("\"foo\"", @as(enum { foo, bar }, .foo), .{ .emit_strings_as_arrays = true });
try testStringify("\"ItBroke\"", error.ItBroke, .{ .emit_strings_as_arrays = true });
// Should work on these:
try testStringify("\"bar\"", @Vector(3, u8){ 'b', 'a', 'r' }, .{});
try testStringify("[98,97,114]", @Vector(3, u8){ 'b', 'a', 'r' }, .{ .emit_strings_as_arrays = true });
try testStringify("\"bar\"", [3]u8{ 'b', 'a', 'r' }, .{});
try testStringify("[98,97,114]", [3]u8{ 'b', 'a', 'r' }, .{ .emit_strings_as_arrays = true });
}
test "stringify struct with indentation" {
try testStringify(
\\{
\\ "foo": 42,
\\ "bar": [
\\ 1,
\\ 2,
\\ 3
\\ ]
\\}
,
struct {
foo: u32,
bar: [3]u32,
}{
.foo = 42,
.bar = .{ 1, 2, 3 },
},
.{ .whitespace = .indent_4 },
);
try testStringify(
"{\n\t\"foo\": 42,\n\t\"bar\": [\n\t\t1,\n\t\t2,\n\t\t3\n\t]\n}",
struct {
foo: u32,
bar: [3]u32,
}{
.foo = 42,
.bar = .{ 1, 2, 3 },
},
.{ .whitespace = .indent_tab },
);
try testStringify(
\\{"foo":42,"bar":[1,2,3]}
,
struct {
foo: u32,
bar: [3]u32,
}{
.foo = 42,
.bar = .{ 1, 2, 3 },
},
.{ .whitespace = .minified },
);
}
test "stringify array of structs" {
const MyStruct = struct {
foo: u32,
};
try testStringify("[{\"foo\":42},{\"foo\":100},{\"foo\":1000}]", [_]MyStruct{
MyStruct{ .foo = 42 },
MyStruct{ .foo = 100 },
MyStruct{ .foo = 1000 },
}, .{});
}
test "stringify struct with custom stringifier" {
try testStringify("[\"something special\",42]", struct {
foo: u32,
const Self = @This();
pub fn jsonStringify(v: @This(), jws: anytype) !void {
_ = v;
try jws.beginArray();
try jws.write("something special");
try jws.write(42);
try jws.endArray();
}
}{ .foo = 42 }, .{});
}
fn testStringify(expected: []const u8, v: anytype, options: Options) !void {
var buffer: [4096]u8 = undefined;
var w: Writer = .fixed(&buffer);
try value(v, options, &w);
try std.testing.expectEqualStrings(expected, w.buffered());
}
test "raw streaming" {
var out_buf: [1024]u8 = undefined;
var out: Writer = .fixed(&out_buf);
var w: Stringify = .{ .writer = &out, .options = .{ .whitespace = .indent_2 } };
try w.beginObject();
try w.beginObjectFieldRaw();
try w.writer.writeAll("\"long");
try w.writer.writeAll(" key\"");
w.endObjectFieldRaw();
try w.beginWriteRaw();
try w.writer.writeAll("\"long");
try w.writer.writeAll(" value\"");
w.endWriteRaw();
try w.endObject();
const expected =
\\{
\\ "long key": "long value"
\\}
;
try std.testing.expectEqualStrings(expected, w.writer.buffered());
}