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#include <mbgl/storage/file_request.hpp>
#include <mbgl/storage/response.hpp>
#include <uv.h>
#include <cassert>
namespace mbgl {
struct FileRequestBaton {
FileRequestBaton(FileRequest *request_, const std::string &path, uv_loop_t *loop)
: thread_id(uv_thread_self()), request(request_) {
req.data = this;
uv_fs_open(loop, &req, path.c_str(), O_RDONLY, S_IRUSR, file_opened);
}
~FileRequestBaton() {
}
void cancel();
static void file_opened(uv_fs_t *req);
static void file_stated(uv_fs_t *req);
static void file_read(uv_fs_t *req);
static void file_closed(uv_fs_t *req);
static void notify_error(uv_fs_t *req);
static void cleanup(uv_fs_t *req);
const unsigned long thread_id;
FileRequest *request = nullptr;
uv_fs_t req;
uv_file fd = -1;
bool canceled = false;
std::string body;
uv_buf_t buffer;
};
void FileRequestBaton::cancel() {
canceled = true;
// uv_cancel fails frequently when the request has already been started.
// In that case, we have to let it complete and check the canceled bool
// instead.
uv_cancel((uv_req_t *)&req);
}
void FileRequestBaton::notify_error(uv_fs_t *req) {
FileRequestBaton *ptr = (FileRequestBaton *)req->data;
assert(ptr->thread_id == uv_thread_self());
if (ptr->request && req->result < 0 && !ptr->canceled && req->result != UV_ECANCELED) {
ptr->request->response = std::unique_ptr<Response>(new Response);
ptr->request->response->code = req->result == UV_ENOENT ? 404 : 500;
ptr->request->response->message = uv_strerror(int(req->result));
ptr->request->notify();
}
}
void FileRequestBaton::file_opened(uv_fs_t *req) {
FileRequestBaton *ptr = (FileRequestBaton *)req->data;
assert(ptr->thread_id == uv_thread_self());
if (req->result < 0) {
// Opening failed or was canceled. There isn't much left we can do.
notify_error(req);
cleanup(req);
} else {
const uv_file fd = uv_file(req->result);
// We're going to reuse this handle, so we need to cleanup first.
uv_fs_req_cleanup(req);
if (ptr->canceled || !ptr->request) {
// Either the FileRequest object has been destructed, or the
// request was canceled.
uv_fs_close(req->loop, req, fd, file_closed);
} else {
ptr->fd = fd;
uv_fs_fstat(req->loop, req, fd, file_stated);
}
}
}
void FileRequestBaton::file_stated(uv_fs_t *req) {
FileRequestBaton *ptr = (FileRequestBaton *)req->data;
assert(ptr->thread_id == uv_thread_self());
if (req->result < 0 || ptr->canceled || !ptr->request) {
// Stating failed or was canceled. We already have an open file handle
// though, which we'll have to close.
notify_error(req);
uv_fs_req_cleanup(req);
uv_fs_close(req->loop, req, ptr->fd, file_closed);
} else {
if (static_cast<const uv_stat_t *>(req->ptr)->st_size > std::numeric_limits<int>::max()) {
// File is too large for us to open this way because uv_buf's only support unsigned
// ints as maximum size.
if (ptr->request) {
ptr->request->response = std::unique_ptr<Response>(new Response);
ptr->request->response->code = UV_EFBIG;
ptr->request->response->message = uv_strerror(UV_EFBIG);
ptr->request->notify();
}
uv_fs_req_cleanup(req);
uv_fs_close(req->loop, req, ptr->fd, file_closed);
} else {
const unsigned int size =
(unsigned int)(static_cast<const uv_stat_t *>(req->ptr)->st_size);
ptr->body.resize(size);
ptr->buffer = uv_buf_init(const_cast<char *>(ptr->body.data()), size);
uv_fs_req_cleanup(req);
uv_fs_read(req->loop, req, ptr->fd, &ptr->buffer, 1, 0, file_read);
}
}
}
void FileRequestBaton::file_read(uv_fs_t *req) {
FileRequestBaton *ptr = (FileRequestBaton *)req->data;
assert(ptr->thread_id == uv_thread_self());
if (req->result < 0 || ptr->canceled || !ptr->request) {
// Stating failed or was canceled. We already have an open file handle
// though, which we'll have to close.
notify_error(req);
} else {
// File was successfully read.
if (ptr->request) {
ptr->request->response = std::unique_ptr<Response>(new Response);
ptr->request->response->code = 200;
ptr->request->response->data = std::move(ptr->body);
ptr->request->notify();
}
}
uv_fs_req_cleanup(req);
uv_fs_close(req->loop, req, ptr->fd, file_closed);
}
void FileRequestBaton::file_closed(uv_fs_t *req) {
FileRequestBaton *ptr = (FileRequestBaton *)req->data;
assert(ptr->thread_id == uv_thread_self());
if (req->result < 0) {
// Closing the file failed. But there isn't anything we can do.
}
cleanup(req);
}
void FileRequestBaton::cleanup(uv_fs_t *req) {
FileRequestBaton *ptr = (FileRequestBaton *)req->data;
assert(ptr->thread_id == uv_thread_self());
if (ptr->request) {
ptr->request->ptr = nullptr;
}
uv_fs_req_cleanup(req);
delete ptr;
}
FileRequest::FileRequest(const std::string &path_, uv_loop_t *loop)
: BaseRequest(), path(path_), thread_id(uv_thread_self()), ptr(new FileRequestBaton(this, path, loop)) {
}
FileRequest::~FileRequest() {
assert(thread_id == uv_thread_self());
if (ptr) {
ptr->cancel();
// When deleting a FileRequest object with a uv_fs_* call is in progress, we are making sure
// that the callback doesn't accidentally reference this object again.
ptr->request = nullptr;
}
}
}
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