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
|
// Copyright (c) 2015 Ryan Prichard
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
//
// ConsoleLine
//
// This data structure keep tracks of the previous CHAR_INFO content of an
// output line and determines when a line has changed. Detecting line changes
// is made complicated by terminal resizing.
//
#include "ConsoleLine.h"
#include <algorithm>
#include "../shared/WinptyAssert.h"
static CHAR_INFO blankChar(WORD attributes)
{
// N.B.: As long as we write to UnicodeChar rather than AsciiChar, there
// are no padding bytes that could contain uninitialized bytes. This fact
// is important for efficient comparison.
CHAR_INFO ret;
ret.Attributes = attributes;
ret.Char.UnicodeChar = L' ';
return ret;
}
static bool isLineBlank(const CHAR_INFO *line, int length, WORD attributes)
{
for (int col = 0; col < length; ++col) {
if (line[col].Attributes != attributes ||
line[col].Char.UnicodeChar != L' ') {
return false;
}
}
return true;
}
static inline bool areLinesEqual(
const CHAR_INFO *line1,
const CHAR_INFO *line2,
int length)
{
return memcmp(line1, line2, sizeof(CHAR_INFO) * length) == 0;
}
ConsoleLine::ConsoleLine() : m_prevLength(0)
{
}
void ConsoleLine::reset()
{
m_prevLength = 0;
m_prevData.clear();
}
// Determines whether the given line is sufficiently different from the
// previously seen line as to justify reoutputting the line. The function
// also sets the `ConsoleLine` to the given line, exactly as if `setLine` had
// been called.
bool ConsoleLine::detectChangeAndSetLine(const CHAR_INFO *const line, const int newLength)
{
ASSERT(newLength >= 1);
ASSERT(m_prevLength <= static_cast<int>(m_prevData.size()));
if (newLength == m_prevLength) {
bool equalLines = areLinesEqual(m_prevData.data(), line, newLength);
if (!equalLines) {
setLine(line, newLength);
}
return !equalLines;
} else {
if (m_prevLength == 0) {
setLine(line, newLength);
return true;
}
ASSERT(m_prevLength >= 1);
const WORD prevBlank = m_prevData[m_prevLength - 1].Attributes;
const WORD newBlank = line[newLength - 1].Attributes;
bool equalLines = false;
if (newLength < m_prevLength) {
// The line has become shorter. The lines are equal if the common
// part is equal, and if the newly truncated characters were blank.
equalLines =
areLinesEqual(m_prevData.data(), line, newLength) &&
isLineBlank(m_prevData.data() + newLength,
m_prevLength - newLength,
newBlank);
} else {
//
// The line has become longer. The lines are equal if the common
// part is equal, and if both the extra characters and any
// potentially reexposed characters are blank.
//
// Two of the most relevant terminals for winpty--mintty and
// jediterm--don't (currently) erase the obscured content when a
// line is cleared, so we should anticipate its existence when
// making a terminal wider and reoutput the line. See:
//
// * https://github.com/mintty/mintty/issues/480
// * https://github.com/JetBrains/jediterm/issues/118
//
ASSERT(newLength > m_prevLength);
equalLines =
areLinesEqual(m_prevData.data(), line, m_prevLength) &&
isLineBlank(m_prevData.data() + m_prevLength,
std::min<int>(m_prevData.size(), newLength) - m_prevLength,
prevBlank) &&
isLineBlank(line + m_prevLength,
newLength - m_prevLength,
prevBlank);
}
setLine(line, newLength);
return !equalLines;
}
}
void ConsoleLine::setLine(const CHAR_INFO *const line, const int newLength)
{
if (static_cast<int>(m_prevData.size()) < newLength) {
m_prevData.resize(newLength);
}
memcpy(m_prevData.data(), line, sizeof(CHAR_INFO) * newLength);
m_prevLength = newLength;
}
void ConsoleLine::blank(WORD attributes)
{
m_prevData.resize(1);
m_prevData[0] = blankChar(attributes);
m_prevLength = 1;
}
|
