1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
|
#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"
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;
};
struct wbuffer {
size_t refcount, size;
char *data;
};
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.
/// @return The newly-allocated `WStream` instance
WStream * wstream_new(size_t maxmem)
{
WStream *rv = xmalloc(sizeof(WStream));
rv->maxmem = maxmem;
rv->stream = NULL;
rv->curmem = 0;
rv->pending_reqs = 0;
rv->freed = false;
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;
}
/// 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)
{
WriteData *data;
uv_buf_t uvbuf;
uv_write_t *req;
// This should not be called after a wstream was freed
assert(!wstream->freed);
if (wstream->curmem + buffer->size > wstream->maxmem) {
return false;
}
buffer->refcount++;
wstream->curmem += buffer->size;
data = xmalloc(sizeof(WriteData));
data->wstream = wstream;
data->buffer = buffer;
req = xmalloc(sizeof(uv_write_t));
req->data = data;
uvbuf.base = buffer->data;
uvbuf.len = buffer->size;
wstream->pending_reqs++;
uv_write(req, wstream->stream, &uvbuf, 1, write_cb);
return true;
}
/// 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 copy If true, the data will be copied into the WBuffer
/// @return The allocated WBuffer instance
WBuffer *wstream_new_buffer(char *data, size_t size, bool copy)
{
WBuffer *rv = xmalloc(sizeof(WBuffer));
rv->size = size;
rv->refcount = 0;
if (copy) {
rv->data = xmemdup(data, size);
} else {
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;
if (!--data->buffer->refcount) {
// Free the data written to the stream
free(data->buffer->data);
free(data->buffer);
}
data->wstream->pending_reqs--;
if (data->wstream->freed && data->wstream->pending_reqs == 0) {
// Last pending write, free the wstream;
free(data->wstream);
}
free(data);
}
|
