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#include <assert.h>
#include <stdint.h>
#include <stdbool.h>
#include <uv.h>
#include "nvim/os/uv_helpers.h"
#include "nvim/os/wstream.h"
#include "nvim/os/wstream_defs.h"
#include "nvim/vim.h"
#include "nvim/memory.h"
#define DEFAULT_MAXMEM 1024 * 1024 * 10
struct wstream {
uv_stream_t *stream;
// Memory currently used by pending buffers
size_t curmem;
// Maximum memory used by this instance
size_t maxmem;
// Number of pending requests
size_t pending_reqs;
bool freed;
// (optional) Write callback and data
wstream_cb cb;
void *data;
};
struct wbuffer {
size_t size, refcount;
char *data;
wbuffer_data_finalizer cb;
};
typedef struct {
WStream *wstream;
WBuffer *buffer;
} WriteData;
#ifdef INCLUDE_GENERATED_DECLARATIONS
# include "os/wstream.c.generated.h"
#endif
/// Creates a new WStream instance. A WStream encapsulates all the boilerplate
/// necessary for writing to a libuv stream.
///
/// @param maxmem Maximum amount memory used by this `WStream` instance. If 0,
/// a default value of 10mb will be used.
/// @return The newly-allocated `WStream` instance
WStream * wstream_new(size_t maxmem)
{
if (!maxmem) {
maxmem = DEFAULT_MAXMEM;
}
WStream *rv = xmalloc(sizeof(WStream));
rv->maxmem = maxmem;
rv->stream = NULL;
rv->curmem = 0;
rv->pending_reqs = 0;
rv->freed = false;
rv->cb = NULL;
return rv;
}
/// Frees all memory allocated for a WStream instance
///
/// @param wstream The `WStream` instance
void wstream_free(WStream *wstream)
{
if (!wstream->pending_reqs) {
free(wstream);
} else {
wstream->freed = true;
}
}
/// Sets the underlying `uv_stream_t` instance
///
/// @param wstream The `WStream` instance
/// @param stream The new `uv_stream_t` instance
void wstream_set_stream(WStream *wstream, uv_stream_t *stream)
{
handle_set_wstream((uv_handle_t *)stream, wstream);
wstream->stream = stream;
}
/// Sets a callback that will be called on completion of a write request,
/// indicating failure/success.
///
/// This affects all requests currently in-flight as well. Overwrites any
/// possible earlier callback.
///
/// @note This callback will not fire if the write request couldn't even be
/// queued properly (i.e.: when `wstream_write() returns an error`).
///
/// @param wstream The `WStream` instance
/// @param cb The callback
/// @param data User-provided data that will be passed to `cb`
void wstream_set_write_cb(WStream *wstream, wstream_cb cb, void *data)
FUNC_ATTR_NONNULL_ARG(1)
{
wstream->cb = cb;
wstream->data = data;
}
/// Queues data for writing to the backing file descriptor of a `WStream`
/// instance. This will fail if the write would cause the WStream use more
/// memory than specified by `maxmem`.
///
/// @param wstream The `WStream` instance
/// @param buffer The buffer which contains data to be written
/// @return false if the write failed
bool wstream_write(WStream *wstream, WBuffer *buffer)
{
// This should not be called after a wstream was freed
assert(!wstream->freed);
if (wstream->curmem > wstream->maxmem) {
goto err;
}
wstream->curmem += buffer->size;
WriteData *data = xmalloc(sizeof(WriteData));
data->wstream = wstream;
data->buffer = buffer;
uv_write_t *req = xmalloc(sizeof(uv_write_t));
req->data = data;
uv_buf_t uvbuf;
uvbuf.base = buffer->data;
uvbuf.len = buffer->size;
if (uv_write(req, wstream->stream, &uvbuf, 1, write_cb)) {
free(data);
free(req);
goto err;
}
wstream->pending_reqs++;
return true;
err:
release_wbuffer(buffer);
return false;
}
/// Creates a WBuffer object for holding output data. Instances of this
/// object can be reused across WStream instances, and the memory is freed
/// automatically when no longer needed(it tracks the number of references
/// internally)
///
/// @param data Data stored by the WBuffer
/// @param size The size of the data array
/// @param refcount The number of references for the WBuffer. This will be used
/// by WStream instances to decide when a WBuffer should be freed.
/// @param cb Pointer to function that will be responsible for freeing
/// the buffer data(passing 'free' will work as expected).
/// @return The allocated WBuffer instance
WBuffer *wstream_new_buffer(char *data,
size_t size,
size_t refcount,
wbuffer_data_finalizer cb)
{
WBuffer *rv = xmalloc(sizeof(WBuffer));
rv->size = size;
rv->refcount = refcount;
rv->cb = cb;
rv->data = data;
return rv;
}
static void write_cb(uv_write_t *req, int status)
{
WriteData *data = req->data;
free(req);
data->wstream->curmem -= data->buffer->size;
release_wbuffer(data->buffer);
data->wstream->pending_reqs--;
if (data->wstream->cb) {
data->wstream->cb(data->wstream,
data->wstream->data,
data->wstream->pending_reqs,
status);
}
if (data->wstream->freed && data->wstream->pending_reqs == 0) {
// Last pending write, free the wstream;
free(data->wstream);
}
free(data);
}
static void release_wbuffer(WBuffer *buffer)
{
if (!--buffer->refcount) {
if (buffer->cb) {
buffer->cb(buffer->data);
}
free(buffer);
}
}
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