1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef NETDUTILS_DUMPWRITER_H_
18 #define NETDUTILS_DUMPWRITER_H_
19 
20 #include <string>
21 
22 namespace android {
23 namespace netdutils {
24 
25 class DumpWriter {
26   public:
27     DumpWriter(int fd);
28 
29     void incIndent();
30     void decIndent();
31 
32     void println(const std::string& line);
33     template <size_t n>
println(const char line[n])34     void println(const char line[n]) {
35         println(std::string(line));
36     }
37     // Hint to the compiler that it should apply printf validation of
38     // arguments (beginning at position 3) of the format (specified in
39     // position 2). Note that position 1 is the implicit "this" argument.
40     void println(const char* fmt, ...) __attribute__((__format__(__printf__, 2, 3)));
blankline()41     void blankline() { println(""); }
42 
43   private:
44     uint8_t mIndentLevel;
45     int mFd;
46 };
47 
48 class ScopedIndent {
49   public:
50     ScopedIndent() = delete;
51     ScopedIndent(const ScopedIndent&) = delete;
52     ScopedIndent(ScopedIndent&&) = delete;
ScopedIndent(DumpWriter & dw)53     explicit ScopedIndent(DumpWriter& dw) : mDw(dw) { mDw.incIndent(); }
~ScopedIndent()54     ~ScopedIndent() { mDw.decIndent(); }
55     ScopedIndent& operator=(const ScopedIndent&) = delete;
56     ScopedIndent& operator=(ScopedIndent&&) = delete;
57 
58     // TODO: consider additional {inc,dec}Indent methods and a counter that
59     // can be used to unwind all pending increments on exit.
60 
61   private:
62     DumpWriter& mDw;
63 };
64 
65 }  // namespace netdutils
66 }  // namespace android
67 
68 #endif  // NETDUTILS_DUMPWRITER_H_
69