Univalue: Do not build JSON escape list at runtime #4715

pull jgarzik wants to merge 1 commits into bitcoin:master from jgarzik:2014_univalue_warn changing 5 files +344 −20

jgarzik commented at 4:17 PM on August 17, 2014: contributor

No need to waste startup time building something that can be done at compile time.

This also resolves a clang++ warning originally reported in #4714, univalue/univalue_write.cpp:33:12: warning: array subscript is of type 'char' [-Wchar-subscripts] escapes['"'] = """; ^~~~

etc.
isghe commented at 4:43 PM on August 17, 2014: contributor

It should be ok having compile time assert, asserting that: [code] compile_time_assert (0 == strcmp (escapes[static_cast<unsigned char>('"')], "\"")); [/code] etc..

or at least a runtime assert on them.

And yes it looks we are missing a compile time initialisation like: [code] escapes[static_cast<unsigned char>('"')] = "\""; [/code] etc..
in .gitignore:None in f30b421531 outdated
```
  27 | @@ -28,6 +28,8 @@ src/m4/ltsugar.m4
  28 |  src/m4/ltversion.m4
  29 |  src/m4/lt~obsolete.m4
  30 |  
  31 | +src/univalue/gen
```
sipa commented at 12:20 AM on August 18, 2014:

gen.cpp?

jgarzik commented at 3:24 AM on August 18, 2014:

No, gen.cpp is not a generated file to be ignored. It definitely should be checked into git.
in src/univalue/univalue_escapes.h:None in f30b421531 outdated
```
   0 | @@ -0,0 +1,262 @@
   1 | +// Automatically generated file. Do not modify.
```
laanwj commented at 7:18 AM on August 18, 2014:

Please add instructions on how to regenerate the file, or at least a mention of what is used to generate it.

jgarzik commented at 2:37 PM on August 18, 2014:

Updated.

laanwj commented at 3:27 PM on August 18, 2014:

I think it's useful to refer to gen.cpp in the generated file as well. After all, someone maintaining this will stumble on this file first.
laanwj commented at 7:21 AM on August 18, 2014: member

Ut ACK, a silly 256 lookup table can be included in the executable, no need to build it at runtime (we do the same for hex digits, base64 decode table etc...).
laanwj added the label Improvement on Aug 18, 2014

Univalue: Do not build JSON escape list at runtime

No need to waste startup time building something that can be done
at compile time.

This also resolves a clang++ warning originally reported in #4714,
univalue/univalue_write.cpp:33:12: warning: array subscript is of type 'char
escapes['"'] = "\\"";
^~~~

etc.

3cceba7abb

BitcoinPullTester commented at 4:02 PM on August 18, 2014: none

Automatic sanity-testing: PASSED, see http://jenkins.bluematt.me/pull-tester/p4715_3cceba7abb22133fcaea8d4f7aaed345f0e48009/ for binaries and test log. This test script verifies pulls every time they are updated. It, however, dies sometimes and fails to test properly. If you are waiting on a test, please check timestamps to verify that the test.log is moving at http://jenkins.bluematt.me/pull-tester/current/ Contact BlueMatt on freenode if something looks broken.
jgarzik merged this on Aug 19, 2014
jgarzik closed this on Aug 19, 2014
jgarzik referenced this in commit 0367329549 on Aug 19, 2014
jgarzik deleted the branch on Aug 24, 2014
MarcoFalke locked this on Sep 8, 2021

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#4714 univalue: avoid warning: array subscript is of type 'char'