factotum/nats.zig
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message: fix header method types and add header iterator

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As I ascertained from reading the code, nats.c does in fact let you set
message headers with null values. However, the library segfaults if
you try to actually send such a message over the wire. So we just
forbid it with stricter typing and assume it's not possible for
someone to send us a message containing headers with a null value as
well.
This commit is contained in:
torque 2023-08-23 01:03:29 -07:00
parent 48962f27d9
commit 3e5840bd84
Signed by: torque
SSH Key Fingerprint: SHA256:nCrXefBNo6EbjNSQhv0nXmEg/VuNq3sMF5b8zETw3Tk
1 changed files with 52 additions and 11 deletions
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63
src/message.zig
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@ -45,36 +45,39 @@ pub const Message = opaque {
return @intCast(nats_c.natsMsg_GetDataLength(@ptrCast(self)));
}
pub fn setHeaderValue(self: *Message, key: [:0]const u8, value: ?[:0]const u8) Error!void {
pub fn setHeaderValue(self: *Message, key: [:0]const u8, value: [:0]const u8) Error!void {
const status = Status.fromInt(nats_c.natsMsgHeader_Set(@ptrCast(self), key.ptr, value.ptr));
return status.raise();
}
pub fn addHeaderValue(self: *Message, key: [:0]const u8, value: ?[:0]const u8) Error!void {
pub fn addHeaderValue(self: *Message, key: [:0]const u8, value: [:0]const u8) Error!void {
const status = Status.fromInt(nats_c.natsMsgHeader_Add(@ptrCast(self), key.ptr, value.ptr));
return status.raise();
}
pub fn getHeaderValue(self: *Message, key: [:0]const u8) Error!?[:0]const u8 {
var value: ?[*]u8 = null;
pub fn getHeaderValue(self: *Message, key: [:0]const u8) Error![:0]const u8 {
var value: ?[*:0]u8 = null;
const status = Status.fromInt(nats_c.natsMsgHeader_Get(@ptrCast(self), key.ptr, &value));
return status.toError() orelse if (value) |val| std.mem.sliceTo(u8, val, 0) else null;
return status.toError() orelse std.mem.sliceTo(value.?, 0);
}
pub fn getAllHeaderValues(self: *Message, key: [:0]const u8) Error![]?[*]const u8 {
var values: [*]?[*]const u8 = undefined;
pub fn getAllHeaderValues(self: *Message, key: [:0]const u8) Error![][*:0]const u8 {
var values: [*c][*c]const u8 = undefined;
var count: c_int = 0;
const status = Status.fromInt(nats_c.natsMsgHeader_Values(@ptrCast(self), key.ptr, &values, &count));
// the user must use std.mem.spanTo on each item they want to read to get a
// slice, since we can't do that automatically without having to allocate.
return status.toError() orelse values[0..@intCast(count)];
return status.toError() orelse blk: {
const coerced: [*][*:0]const u8 = @ptrFromInt(@intFromPtr(values));
break :blk coerced[0..@intCast(count)];
};
}
pub fn getAllHeaderKeys(self: *Message) Error![][*]const u8 {
var keys: [*][*]const u8 = undefined;
pub fn getAllHeaderKeys(self: *Message) Error![][*:0]const u8 {
var keys: [*c][*c]const u8 = undefined;
var count: c_int = 0;
const status = Status.fromInt(nats_c.natsMsgHeader_Keys(@ptrCast(self), &keys, &count));
@ -83,7 +86,45 @@ pub const Message = opaque {
// the user must use std.mem.spanTo on each item they want to read to get a
// slice, since we can't do that automatically without having to allocate.
return status.toError() orelse keys[0..@intCast(count)];
// the returned slice
return status.toError() orelse blk: {
const coerced: [*][*:0]const u8 = @ptrFromInt(@intFromPtr(keys));
break :blk coerced[0..@intCast(count)];
};
}
pub const HeaderIterator = struct {
message: *Message,
keys: [][*:0]const u8,
index: usize = 0,
pub fn destroy(self: *HeaderIterator) void {
std.heap.raw_c_allocator.free(self.keys);
}
pub fn next(self: *HeaderIterator) Error!?struct { key: [:0]const u8, value: ?[:0]const u8 } {
if (self.index >= self.keys.len) return null;
defer self.index += 1;
const sliced = std.mem.sliceTo(self.keys[self.index], 0);
return .{
.key = sliced,
.value = try self.message.getHeaderValue(sliced),
};
}
pub fn nextKey(self: *HeaderIterator) ?[:0]const u8 {
if (self.index >= self.keys.len) return null;
defer self.index += 1;
return std.mem.sliceTo(self.keys[self.index], 0);
}
};
pub fn headerIterator(self: *Message) Error!HeaderIterator {
return .{
.message = self,
.keys = try self.getAllHeaderKeys(),
};
}
pub fn deleteHeader(self: *Message, key: [:0]const u8) Error!void {