FlexiLib/src/interface.zig

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const std = @import("std");
pub const Header = extern struct {
name_ptr: [*]u8,
name_len: usize,
value_ptr: [*]u8,
value_len: usize,
};
pub const Response = extern struct {
ptr: [*]u8,
len: usize,
headers: [*]Header,
headers_len: usize,
};
pub const Request = extern struct {
method: [*:0]u8,
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method_len: usize,
content: [*]u8,
content_len: usize,
headers: [*]Header,
headers_len: usize,
};
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pub fn toHeaders(alloc: std.mem.Allocator, headers: std.StringHashMap([]const u8)) ![*]Header {
var header_array = try std.ArrayList(Header).initCapacity(alloc, headers.count());
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var iterator = headers.iterator();
while (iterator.next()) |kv| {
header_array.appendAssumeCapacity(.{
.name_ptr = @constCast(kv.key_ptr.*).ptr,
.name_len = kv.key_ptr.*.len,
.value_ptr = @constCast(kv.value_ptr.*).ptr,
.value_len = kv.value_ptr.*.len,
});
}
return header_array.items.ptr;
}
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var allocator: ?*std.mem.Allocator = null;
pub const ZigResponse = struct {
body: *std.ArrayList(u8),
headers: *std.StringHashMap([]const u8),
};
/// This function is optional and can be exported by zig libraries for
/// initialization. If exported, it will be called once in the beginning of
/// a request and will be provided a pointer to std.mem.Allocator, which is
/// useful for reusing the parent allocator
pub fn zigInit(parent_allocator: *anyopaque) callconv(.C) void {
allocator = @ptrCast(*std.mem.Allocator, @alignCast(@alignOf(*std.mem.Allocator), parent_allocator));
}
pub const ZigRequestHandler = *const fn (std.mem.Allocator, Request, ZigResponse) anyerror!void;
const log = std.log.scoped(.interface);
pub fn handleRequest(request: *Request, zigRequestHandler: ZigRequestHandler) ?*Response {
// TODO: implement another library in C or Rust or something to show
// that anything using a C ABI can be successful
var alloc = if (allocator) |a| a.* else @panic("zigInit not called prior to handle_request. This is a coding error");
// setup response body
var response = std.ArrayList(u8).init(alloc);
// setup headers
var headers = std.StringHashMap([]const u8).init(alloc);
zigRequestHandler(alloc, request.*, .{
.body = &response,
.headers = &headers,
}) catch |e| {
log.err("Unexpected error processing request: {any}", .{e});
if (@errorReturnTrace()) |trace| {
std.debug.dumpStackTrace(trace.*);
}
return null;
};
log.debug("response ptr: {*}", .{response.items.ptr});
// Marshall data back for handling by server
var rc = alloc.create(Response) catch @panic("OOM");
rc.ptr = response.items.ptr;
rc.len = response.items.len;
rc.headers = toHeaders(alloc, headers) catch |e| {
log.err("Unexpected error processing request: {any}", .{e});
if (@errorReturnTrace()) |trace| {
std.debug.dumpStackTrace(trace.*);
}
return null;
};
rc.headers_len = headers.count();
return rc;
}