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Move ElideMiddle() to its own source file.
Move the function to its own source file since it is no longer trivial (and will get optimized in future patches). + Add a new ElideMiddleInPlace() function that doesn't do anything if no elision is required + use it in status.cc. + Add a new elide_middle_perftest program to benchmark the performance of the function. On my machine, the 'avg' result is 159.9ms.
1 parent 60f901e commit 2d7ee52

10 files changed

+274
-127
lines changed

‎CMakeLists.txt

+3
Original file line numberDiff line numberDiff line change
@@ -135,6 +135,7 @@ add_library(libninja OBJECT
135135
src/deps_log.cc
136136
src/disk_interface.cc
137137
src/edit_distance.cc
138+
src/elide_middle.cc
138139
src/eval_env.cc
139140
src/graph.cc
140141
src/graphviz.cc
@@ -265,6 +266,7 @@ if(BUILD_TESTING)
265266
src/disk_interface_test.cc
266267
src/dyndep_parser_test.cc
267268
src/edit_distance_test.cc
269+
src/elide_middle_test.cc
268270
src/explanations_test.cc
269271
src/graph_test.cc
270272
src/json_test.cc
@@ -295,6 +297,7 @@ if(BUILD_TESTING)
295297
canon_perftest
296298
clparser_perftest
297299
depfile_parser_perftest
300+
elide_middle_perftest
298301
hash_collision_bench
299302
manifest_parser_perftest
300303
)

‎configure.py

+3
Original file line numberDiff line numberDiff line change
@@ -539,6 +539,7 @@ def has_re2c() -> bool:
539539
'dyndep',
540540
'dyndep_parser',
541541
'edit_distance',
542+
'elide_middle',
542543
'eval_env',
543544
'graph',
544545
'graphviz',
@@ -638,6 +639,7 @@ def has_re2c() -> bool:
638639
'disk_interface_test',
639640
'dyndep_parser_test',
640641
'edit_distance_test',
642+
'elide_middle_test',
641643
'explanations_test',
642644
'graph_test',
643645
'json_test',
@@ -683,6 +685,7 @@ def has_re2c() -> bool:
683685

684686
for name in ['build_log_perftest',
685687
'canon_perftest',
688+
'elide_middle_perftest',
686689
'depfile_parser_perftest',
687690
'hash_collision_bench',
688691
'manifest_parser_perftest',

‎src/elide_middle.cc

+65
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,65 @@
1+
// Copyright 2024 Google Inc. All Rights Reserved.
2+
//
3+
// Licensed under the Apache License, Version 2.0 (the "License");
4+
// you may not use this file except in compliance with the License.
5+
// You may obtain a copy of the License at
6+
//
7+
// http://www.apache.org/licenses/LICENSE-2.0
8+
//
9+
// Unless required by applicable law or agreed to in writing, software
10+
// distributed under the License is distributed on an "AS IS" BASIS,
11+
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12+
// See the License for the specific language governing permissions and
13+
// limitations under the License.
14+
15+
#include "elide_middle.h"
16+
17+
#include <assert.h>
18+
#include <string.h>
19+
20+
#include <regex>
21+
22+
void ElideMiddleInPlace(std::string& str, size_t max_width) {
23+
if (max_width <= 3) {
24+
str.assign("...", max_width);
25+
return;
26+
}
27+
const int kMargin = 3; // Space for "...".
28+
const static std::regex ansi_escape("\\x1b[^m]*m");
29+
std::string result = std::regex_replace(str, ansi_escape, "");
30+
if (result.size() <= max_width)
31+
return;
32+
33+
int32_t elide_size = (max_width - kMargin) / 2;
34+
35+
std::vector<std::pair<int32_t, std::string>> escapes;
36+
size_t added_len = 0; // total number of characters
37+
38+
std::sregex_iterator it(str.begin(), str.end(), ansi_escape);
39+
std::sregex_iterator end;
40+
while (it != end) {
41+
escapes.emplace_back(it->position() - added_len, it->str());
42+
added_len += it->str().size();
43+
++it;
44+
}
45+
46+
std::string new_status =
47+
result.substr(0, elide_size) + "..." +
48+
result.substr(result.size() - elide_size - ((max_width - kMargin) % 2));
49+
50+
added_len = 0;
51+
// We need to put all ANSI escape codes back in:
52+
for (const auto& escape : escapes) {
53+
int32_t pos = escape.first;
54+
if (pos > elide_size) {
55+
pos -= result.size() - max_width;
56+
if (pos < static_cast<int32_t>(max_width) - elide_size) {
57+
pos = max_width - elide_size - (max_width % 2 == 0 ? 1 : 0);
58+
}
59+
}
60+
pos += added_len;
61+
new_status.insert(pos, escape.second);
62+
added_len += escape.second.size();
63+
}
64+
str = std::move(new_status);
65+
}

‎src/elide_middle.h

+27
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,27 @@
1+
// Copyright 2024 Google Inc. All Rights Reserved.
2+
//
3+
// Licensed under the Apache License, Version 2.0 (the "License");
4+
// you may not use this file except in compliance with the License.
5+
// You may obtain a copy of the License at
6+
//
7+
// http://www.apache.org/licenses/LICENSE-2.0
8+
//
9+
// Unless required by applicable law or agreed to in writing, software
10+
// distributed under the License is distributed on an "AS IS" BASIS,
11+
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12+
// See the License for the specific language governing permissions and
13+
// limitations under the License.
14+
15+
#ifndef NINJA_ELIDE_MIDDLE_H_
16+
#define NINJA_ELIDE_MIDDLE_H_
17+
18+
#include <cstddef>
19+
#include <string>
20+
21+
/// Elide the given string @a str with '...' in the middle if the length
22+
/// exceeds @a max_width. Note that this handles ANSI color sequences
23+
/// properly (non-color related sequences are ignored, but using them
24+
/// would wreak the cursor position or terminal state anyway).
25+
void ElideMiddleInPlace(std::string& str, size_t max_width);
26+
27+
#endif // NINJA_ELIDE_MIDDLE_H_

‎src/elide_middle_perftest.cc

+72
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,72 @@
1+
// Copyright 2024 Google Inc. All Rights Reserved.
2+
//
3+
// Licensed under the Apache License, Version 2.0 (the "License");
4+
// you may not use this file except in compliance with the License.
5+
// You may obtain a copy of the License at
6+
//
7+
// http://www.apache.org/licenses/LICENSE-2.0
8+
//
9+
// Unless required by applicable law or agreed to in writing, software
10+
// distributed under the License is distributed on an "AS IS" BASIS,
11+
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12+
// See the License for the specific language governing permissions and
13+
// limitations under the License.
14+
15+
#include <stdint.h>
16+
#include <stdio.h>
17+
#include <stdlib.h>
18+
#include <string.h>
19+
20+
#include <vector>
21+
22+
#include "elide_middle.h"
23+
#include "metrics.h"
24+
25+
static const char* kTestInputs[] = {
26+
"01234567890123456789",
27+
"012345\x1B[0;35m67890123456789",
28+
"abcd\x1b[1;31mefg\x1b[0mhlkmnopqrstuvwxyz",
29+
};
30+
31+
int main() {
32+
std::vector<int> times;
33+
34+
int64_t kMaxTimeMillis = 5 * 1000;
35+
int64_t base_time = GetTimeMillis();
36+
37+
const int kRuns = 100;
38+
for (int j = 0; j < kRuns; ++j) {
39+
int64_t start = GetTimeMillis();
40+
if (start >= base_time + kMaxTimeMillis)
41+
break;
42+
43+
const int kNumRepetitions = 2000;
44+
for (int count = kNumRepetitions; count > 0; --count) {
45+
for (const char* input : kTestInputs) {
46+
size_t input_len = ::strlen(input);
47+
for (size_t max_width = input_len; max_width > 0; --max_width) {
48+
std::string str(input, input_len);
49+
ElideMiddleInPlace(str, max_width);
50+
}
51+
}
52+
}
53+
54+
int delta = (int)(GetTimeMillis() - start);
55+
times.push_back(delta);
56+
}
57+
58+
int min = times[0];
59+
int max = times[0];
60+
float total = 0;
61+
for (size_t i = 0; i < times.size(); ++i) {
62+
total += times[i];
63+
if (times[i] < min)
64+
min = times[i];
65+
else if (times[i] > max)
66+
max = times[i];
67+
}
68+
69+
printf("min %dms max %dms avg %.1fms\n", min, max, total / times.size());
70+
71+
return 0;
72+
}

‎src/elide_middle_test.cc

+101
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,101 @@
1+
// Copyright 2024 Google Inc. All Rights Reserved.
2+
//
3+
// Licensed under the Apache License, Version 2.0 (the "License");
4+
// you may not use this file except in compliance with the License.
5+
// You may obtain a copy of the License at
6+
//
7+
// http://www.apache.org/licenses/LICENSE-2.0
8+
//
9+
// Unless required by applicable law or agreed to in writing, software
10+
// distributed under the License is distributed on an "AS IS" BASIS,
11+
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12+
// See the License for the specific language governing permissions and
13+
// limitations under the License.
14+
15+
#include "elide_middle.h"
16+
17+
#include "test.h"
18+
19+
namespace {
20+
21+
std::string ElideMiddle(const std::string& str, size_t width) {
22+
std::string result = str;
23+
ElideMiddleInPlace(result, width);
24+
return result;
25+
}
26+
27+
} // namespace
28+
29+
30+
TEST(ElideMiddle, NothingToElide) {
31+
std::string input = "Nothing to elide in this short string.";
32+
EXPECT_EQ(input, ElideMiddle(input, 80));
33+
EXPECT_EQ(input, ElideMiddle(input, 38));
34+
EXPECT_EQ("", ElideMiddle(input, 0));
35+
EXPECT_EQ(".", ElideMiddle(input, 1));
36+
EXPECT_EQ("..", ElideMiddle(input, 2));
37+
EXPECT_EQ("...", ElideMiddle(input, 3));
38+
}
39+
40+
TEST(ElideMiddle, ElideInTheMiddle) {
41+
std::string input = "01234567890123456789";
42+
EXPECT_EQ("...9", ElideMiddle(input, 4));
43+
EXPECT_EQ("0...9", ElideMiddle(input, 5));
44+
EXPECT_EQ("012...789", ElideMiddle(input, 9));
45+
EXPECT_EQ("012...6789", ElideMiddle(input, 10));
46+
EXPECT_EQ("0123...6789", ElideMiddle(input, 11));
47+
EXPECT_EQ("01234567...23456789", ElideMiddle(input, 19));
48+
EXPECT_EQ("01234567890123456789", ElideMiddle(input, 20));
49+
}
50+
51+
// A few ANSI escape sequences. These macros make the following
52+
// test easier to read and understand.
53+
#define MAGENTA "\x1B[0;35m"
54+
#define NOTHING "\33[m"
55+
#define RED "\x1b[1;31m"
56+
#define RESET "\x1b[0m"
57+
58+
TEST(ElideMiddle, ElideAnsiEscapeCodes) {
59+
std::string input = "012345" MAGENTA "67890123456789";
60+
EXPECT_EQ("012..." MAGENTA "6789", ElideMiddle(input, 10));
61+
EXPECT_EQ("012345" MAGENTA "67...23456789", ElideMiddle(input, 19));
62+
63+
EXPECT_EQ("Nothing " NOTHING " string.",
64+
ElideMiddle("Nothing " NOTHING " string.", 18));
65+
EXPECT_EQ("0" NOTHING "12...6789",
66+
ElideMiddle("0" NOTHING "1234567890123456789", 10));
67+
68+
input = "abcd" RED "efg" RESET "hlkmnopqrstuvwxyz";
69+
EXPECT_EQ("", ElideMiddle(input, 0));
70+
EXPECT_EQ(".", ElideMiddle(input, 1));
71+
EXPECT_EQ("..", ElideMiddle(input, 2));
72+
EXPECT_EQ("...", ElideMiddle(input, 3));
73+
EXPECT_EQ("..." RED RESET "z", ElideMiddle(input, 4));
74+
EXPECT_EQ("a..." RED RESET "z", ElideMiddle(input, 5));
75+
EXPECT_EQ("a..." RED RESET "yz", ElideMiddle(input, 6));
76+
EXPECT_EQ("ab..." RED RESET "yz", ElideMiddle(input, 7));
77+
EXPECT_EQ("ab..." RED RESET "xyz", ElideMiddle(input, 8));
78+
EXPECT_EQ("abc..." RED RESET "xyz", ElideMiddle(input, 9));
79+
EXPECT_EQ("abc..." RED RESET "wxyz", ElideMiddle(input, 10));
80+
EXPECT_EQ("abcd" RED "..." RESET "wxyz", ElideMiddle(input, 11));
81+
EXPECT_EQ("abcd" RED "..." RESET "vwxyz", ElideMiddle(input, 12));
82+
83+
EXPECT_EQ("abcd" RED "ef..." RESET "uvwxyz", ElideMiddle(input, 15));
84+
EXPECT_EQ("abcd" RED "ef..." RESET "tuvwxyz", ElideMiddle(input, 16));
85+
EXPECT_EQ("abcd" RED "efg" RESET "...tuvwxyz", ElideMiddle(input, 17));
86+
EXPECT_EQ("abcd" RED "efg" RESET "...stuvwxyz", ElideMiddle(input, 18));
87+
EXPECT_EQ("abcd" RED "efg" RESET "h...stuvwxyz", ElideMiddle(input, 19));
88+
89+
input = "abcdef" RED "A" RESET "BC";
90+
EXPECT_EQ("..." RED RESET "C", ElideMiddle(input, 4));
91+
EXPECT_EQ("a..." RED RESET "C", ElideMiddle(input, 5));
92+
EXPECT_EQ("a..." RED RESET "BC", ElideMiddle(input, 6));
93+
EXPECT_EQ("ab..." RED RESET "BC", ElideMiddle(input, 7));
94+
EXPECT_EQ("ab..." RED "A" RESET "BC", ElideMiddle(input, 8));
95+
EXPECT_EQ("abcdef" RED "A" RESET "BC", ElideMiddle(input, 9));
96+
}
97+
98+
#undef RESET
99+
#undef RED
100+
#undef NOTHING
101+
#undef MAGENTA

‎src/line_printer.cc

+3-2
Original file line numberDiff line numberDiff line change
@@ -28,6 +28,7 @@
2828
#include <sys/time.h>
2929
#endif
3030

31+
#include "elide_middle.h"
3132
#include "util.h"
3233

3334
using namespace std;
@@ -81,7 +82,7 @@ void LinePrinter::Print(string to_print, LineType type) {
8182
CONSOLE_SCREEN_BUFFER_INFO csbi;
8283
GetConsoleScreenBufferInfo(console_, &csbi);
8384

84-
to_print = ElideMiddle(to_print, static_cast<size_t>(csbi.dwSize.X));
85+
ElideMiddleInPlace(to_print, static_cast<size_t>(csbi.dwSize.X));
8586
if (supports_color_) { // this means ENABLE_VIRTUAL_TERMINAL_PROCESSING
8687
// succeeded
8788
printf("%s\x1B[K", to_print.c_str()); // Clear to end of line.
@@ -108,7 +109,7 @@ void LinePrinter::Print(string to_print, LineType type) {
108109
// line-wrapping.
109110
winsize size;
110111
if ((ioctl(STDOUT_FILENO, TIOCGWINSZ, &size) == 0) && size.ws_col) {
111-
to_print = ElideMiddle(to_print, size.ws_col);
112+
ElideMiddleInPlace(to_print, size.ws_col);
112113
}
113114
printf("%s", to_print.c_str());
114115
printf("\x1B[K"); // Clear to end of line.

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