1 // Copyright 2011 The Kyua Authors.
2 // All rights reserved.
3 //
4 // Redistribution and use in source and binary forms, with or without
5 // modification, are permitted provided that the following conditions are
6 // met:
7 //
8 // * Redistributions of source code must retain the above copyright
9 // notice, this list of conditions and the following disclaimer.
10 // * Redistributions in binary form must reproduce the above copyright
11 // notice, this list of conditions and the following disclaimer in the
12 // documentation and/or other materials provided with the distribution.
13 // * Neither the name of Google Inc. nor the names of its contributors
14 // may be used to endorse or promote products derived from this software
15 // without specific prior written permission.
16 //
17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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20 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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24 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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26 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28
29 #include "utils/stream.hpp"
30
31 #include <fstream>
32 #include <iostream>
33 #include <sstream>
34 #include <stdexcept>
35
36 #include "utils/format/macros.hpp"
37 #include "utils/fs/path.hpp"
38 #include "utils/sanity.hpp"
39
40 namespace fs = utils::fs;
41
42
43 namespace {
44
45
46 /// Constant that represents the path to stdout.
47 static const fs::path stdout_path("/dev/stdout");
48
49
50 /// Constant that represents the path to stderr.
51 static const fs::path stderr_path("/dev/stderr");
52
53
54 } // anonymous namespace
55
56
57 /// Opens a new file for output, respecting the stdout and stderr streams.
58 ///
59 /// \param path The path to the output file to be created.
60 ///
61 /// \return A pointer to a new output stream.
62 std::auto_ptr< std::ostream >
open_ostream(const fs::path & path)63 utils::open_ostream(const fs::path& path)
64 {
65 std::auto_ptr< std::ostream > out;
66 if (path == stdout_path) {
67 out.reset(new std::ofstream());
68 out->copyfmt(std::cout);
69 out->clear(std::cout.rdstate());
70 out->rdbuf(std::cout.rdbuf());
71 } else if (path == stderr_path) {
72 out.reset(new std::ofstream());
73 out->copyfmt(std::cerr);
74 out->clear(std::cerr.rdstate());
75 out->rdbuf(std::cerr.rdbuf());
76 } else {
77 out.reset(new std::ofstream(path.c_str()));
78 if (!(*out)) {
79 throw std::runtime_error(F("Cannot open output file %s") % path);
80 }
81 }
82 INV(out.get() != NULL);
83 return out;
84 }
85
86
87 /// Gets the length of a stream.
88 ///
89 /// \param is The input stream for which to calculate its length.
90 ///
91 /// \return The length of the stream. This is of size_t type instead of
92 /// directly std::streampos to simplify the caller. Some systems do not
93 /// support comparing a std::streampos directly to an integer (see
94 /// NetBSD 1.5.x), which is what we often want to do.
95 ///
96 /// \throw std::exception If calculating the length fails due to a stream error.
97 std::size_t
stream_length(std::istream & is)98 utils::stream_length(std::istream& is)
99 {
100 const std::streampos current_pos = is.tellg();
101 try {
102 is.seekg(0, std::ios::end);
103 const std::streampos length = is.tellg();
104 is.seekg(current_pos, std::ios::beg);
105 return static_cast< std::size_t >(length);
106 } catch (...) {
107 is.seekg(current_pos, std::ios::beg);
108 throw;
109 }
110 }
111
112
113 /// Reads a whole file into memory.
114 ///
115 /// \param path The file to read.
116 ///
117 /// \return A plain string containing the raw contents of the file.
118 ///
119 /// \throw std::runtime_error If the file cannot be opened.
120 std::string
read_file(const fs::path & path)121 utils::read_file(const fs::path& path)
122 {
123 std::ifstream input(path.c_str());
124 if (!input)
125 throw std::runtime_error(F("Failed to open '%s' for read") % path);
126 return read_stream(input);
127 }
128
129
130 /// Reads the whole contents of a stream into memory.
131 ///
132 /// \param input The input stream from which to read.
133 ///
134 /// \return A plain string containing the raw contents of the file.
135 std::string
read_stream(std::istream & input)136 utils::read_stream(std::istream& input)
137 {
138 std::ostringstream buffer;
139
140 char tmp[1024];
141 while (input.good()) {
142 input.read(tmp, sizeof(tmp));
143 if (input.good() || input.eof()) {
144 buffer.write(tmp, input.gcount());
145 }
146 }
147
148 return buffer.str();
149 }
150