1//===- split-file.cpp - Input splitting utility ---------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Split input into multipe parts separated by regex '^(.|//)--- ' and extract
10// the specified part.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/ADT/DenseMap.h"
15#include "llvm/ADT/StringExtras.h"
16#include "llvm/ADT/StringRef.h"
17#include "llvm/Support/CommandLine.h"
18#include "llvm/Support/FileOutputBuffer.h"
19#include "llvm/Support/FileSystem.h"
20#include "llvm/Support/LineIterator.h"
21#include "llvm/Support/MemoryBuffer.h"
22#include "llvm/Support/Path.h"
23#include "llvm/Support/ToolOutputFile.h"
24#include "llvm/Support/WithColor.h"
25#include <string>
26#include <system_error>
27
28using namespace llvm;
29
30static cl::OptionCategory cat("split-file Options");
31
32static cl::opt<std::string> input(cl::Positional, cl::desc("filename"),
33 cl::cat(cat));
34
35static cl::opt<std::string> output(cl::Positional, cl::desc("directory"),
36 cl::value_desc("directory"), cl::cat(cat));
37
38static cl::opt<bool> leadingLines("leading-lines",
39 cl::desc("Preserve line numbers"),
40 cl::cat(cat));
41
42static cl::opt<bool> noLeadingLines("no-leading-lines",
43 cl::desc("Don't preserve line numbers (default)"),
44 cl::cat(cat));
45
46static StringRef toolName;
47static int errorCount;
48
49[[noreturn]] static void fatal(StringRef filename, const Twine &message) {
50 if (filename.empty())
51 WithColor::error(OS&: errs(), Prefix: toolName) << message << '\n';
52 else
53 WithColor::error(OS&: errs(), Prefix: toolName) << filename << ": " << message << '\n';
54 exit(status: 1);
55}
56
57static void error(StringRef filename, int64_t line, const Twine &message) {
58 ++errorCount;
59 errs() << filename << ':' << line << ": ";
60 WithColor::error(OS&: errs()) << message << '\n';
61}
62
63namespace {
64struct Part {
65 const char *begin = nullptr;
66 const char *end = nullptr;
67 int64_t leadingLines = 0;
68};
69} // namespace
70
71static int handle(MemoryBuffer &inputBuf, StringRef input) {
72 DenseMap<StringRef, Part> partToBegin;
73 StringRef lastPart, separator;
74 StringRef EOL = inputBuf.getBuffer().detectEOL();
75 for (line_iterator i(inputBuf, /*SkipBlanks=*/false, '\0'); !i.is_at_eof();) {
76 const int64_t lineNo = i.line_number();
77 const StringRef line = *i++;
78 const size_t markerLen = line.starts_with(Prefix: "//") ? 6 : 5;
79 if (!(line.size() >= markerLen &&
80 line.substr(Start: markerLen - 4).starts_with(Prefix: "--- ")))
81 continue;
82 separator = line.substr(Start: 0, N: markerLen);
83 const StringRef partName = line.substr(Start: markerLen);
84 if (partName.empty()) {
85 error(filename: input, line: lineNo, message: "empty part name");
86 continue;
87 }
88 if (isSpace(C: partName.front()) || isSpace(C: partName.back())) {
89 error(filename: input, line: lineNo, message: "part name cannot have leading or trailing space");
90 continue;
91 }
92
93 auto res = partToBegin.try_emplace(Key: partName);
94 if (!res.second) {
95 error(filename: input, line: lineNo,
96 message: "'" + separator + partName + "' occurs more than once");
97 continue;
98 }
99 if (!lastPart.empty())
100 partToBegin[lastPart].end = line.data();
101 Part &cur = res.first->second;
102 if (!i.is_at_eof())
103 cur.begin = i->data();
104 // If --leading-lines is specified, numEmptyLines is 0. Append newlines so
105 // that the extracted part preserves line numbers.
106 cur.leadingLines = leadingLines ? i.line_number() - 1 : 0;
107
108 lastPart = partName;
109 }
110 if (lastPart.empty())
111 fatal(filename: input, message: "no part separator was found");
112 if (errorCount)
113 return 1;
114 partToBegin[lastPart].end = inputBuf.getBufferEnd();
115
116 std::vector<std::unique_ptr<ToolOutputFile>> outputFiles;
117 SmallString<256> partPath;
118 for (auto &keyValue : partToBegin) {
119 partPath.clear();
120 sys::path::append(path&: partPath, a: output, b: keyValue.first);
121 std::error_code ec =
122 sys::fs::create_directories(path: sys::path::parent_path(path: partPath));
123 if (ec)
124 fatal(filename: input, message: ec.message());
125 auto f = std::make_unique<ToolOutputFile>(args: partPath.str(), args&: ec,
126 args: llvm::sys::fs::OF_Text);
127 if (!f)
128 fatal(filename: input, message: ec.message());
129
130 Part &part = keyValue.second;
131 for (int64_t i = 0; i != part.leadingLines; ++i)
132 (*f).os() << EOL;
133 if (part.begin)
134 (*f).os().write(Ptr: part.begin, Size: part.end - part.begin);
135 outputFiles.push_back(x: std::move(f));
136 }
137
138 for (std::unique_ptr<ToolOutputFile> &outputFile : outputFiles)
139 outputFile->keep();
140 return 0;
141}
142
143int main(int argc, const char **argv) {
144 toolName = sys::path::stem(path: argv[0]);
145 cl::HideUnrelatedOptions(Categories: {&cat});
146 cl::ParseCommandLineOptions(
147 argc, argv,
148 Overview: "Split input into multiple parts separated by regex '^(.|//)--- ' and "
149 "extract the part specified by '^(.|//)--- <part>'\n",
150 Errs: nullptr,
151 /*EnvVar=*/nullptr,
152 /*LongOptionsUseDoubleDash=*/true);
153
154 if (input.empty())
155 fatal(filename: "", message: "input filename is not specified");
156 if (output.empty())
157 fatal(filename: "", message: "output directory is not specified");
158 ErrorOr<std::unique_ptr<MemoryBuffer>> bufferOrErr =
159 MemoryBuffer::getFileOrSTDIN(Filename: input, /*IsText=*/true);
160 if (std::error_code ec = bufferOrErr.getError())
161 fatal(filename: input, message: ec.message());
162
163 // Delete output if it is a file or an empty directory, so that we can create
164 // a directory.
165 sys::fs::file_status status;
166 if (std::error_code ec = sys::fs::status(path: output, result&: status))
167 if (ec.value() != static_cast<int>(std::errc::no_such_file_or_directory))
168 fatal(filename: output, message: ec.message());
169 if (status.type() != sys::fs::file_type::file_not_found &&
170 status.type() != sys::fs::file_type::directory_file &&
171 status.type() != sys::fs::file_type::regular_file)
172 fatal(filename: output, message: "output cannot be a special file");
173 if (std::error_code ec = sys::fs::remove(path: output, /*IgnoreNonExisting=*/true))
174 if (ec.value() != static_cast<int>(std::errc::directory_not_empty) &&
175 ec.value() != static_cast<int>(std::errc::file_exists))
176 fatal(filename: output, message: ec.message());
177 return handle(inputBuf&: **bufferOrErr, input);
178}
179