Skip to content

Commit

Permalink
fix: read_history() multiple times will add repeat histories to histo…
Browse files Browse the repository at this point in the history
…ry lists

Issue Description:

When sdcv found multiple items, whatever your choice is, sdcv will add
double the current history entries to history file. For example, if
current history is "a\nb", you search akjk and there's multiple results,
whatever you choose, even -1,  after this is done, the history file will
be rewritten to "a\nb\nakjk\na\nb", note here \n is newline character.
So if you have 500 lines of history, you search akjk and there's
multiple results, you choose -1, after done there's 1001 lines of
history.

How to reproduce:

You can download this dictionary file
https://github.com/skywind3000/ECDICT/releases/download/1.0.28/ecdict-stardict-28.zip
and put into your dictionary directory, on Arch, with AUR, you can
install from https://aur.archlinux.org/packages/stardict-ecdict. Then,
make sure you also add the dictionary name to ~/.config/sdcv_ordering if
you have one. Add some lines to your history file if you do not have.
Then search for "akjk" with sdcv, e,g, `sdcv akjk`, then it will prompt
you to choose, you can choose -1, then ctrl-d to exit. Expected result
is history file add akjk at the end. Actual result is history file now
contain original content + akjk + original content duplicate as I
described in the issue description.

Fix and reasons:

I'm a hobbyist and I'm not a professional, I haven't use C++ for years
so many of my writings is very likely wrong. After some trail and error,
I found that call read_history() multiple times will add repeat
histories to history lists. In the commit d2327e2, a new IReadLine
object is created (note name changes, also note I know this description
of a IReadLine object is wrong). Here's a permalink:
https://github.com/Dushistov/sdcv/blob/49c8094b53b7dd90efeabeaf276752a650a0f931/src/libwrapper.cpp#L418.
The problem of this new IReadLine object `choice_readline` is it called
read_history() again from ./src/readline.cpp constructor, because
there's already a IReadLine object `io` constructed at ./src/sdcv.cpp.
When read_history() is called twice, there's a "history lists" read from
history file first then append from history file again, so when you
destruct IReadLine object with write_history() in ./src/readline.cpp,
the history file contain duplicate content after write. Here are
permalinks:
https://github.com/Dushistov/sdcv/blob/49c8094b53b7dd90efeabeaf276752a650a0f931/src/readline.cpp#L88,
and
https://github.com/Dushistov/sdcv/blob/49c8094b53b7dd90efeabeaf276752a650a0f931/src/readline.cpp#L94.

So my fix is to just to use `io` IReadLine object and not to create a
new `choice_readline` object.

Misc:

During my trial and errors process, I made an example code to show
read_history()'s weird behavior. I did not dig deeper, I just guess
maybe there's some kind of werid history list as mentioned in
https://tiswww.cwru.edu/php/chet/readline/history.html#History-List-Management.

Here's the example code a.c, note you need to include stdio.h,
readline/history.h, and readline/readline.h. I did not include them here
because commit message seems will make them comment.
```c
...
int main (void)
{
	rl_readline_name="learn_readline";
	using_history();
	read_history("/home/xyz/test/learn_readline/history.txt");
	write_history("/home/xyz/test/learn_readline/history2.txt");
	{
		rl_readline_name="learn_readline";
		using_history();
		read_history("/home/xyz/test/learn_readline/history.txt");
		write_history("/home/xyz/test/learn_readline/history3.txt");
	}
	write_history("/home/xyz/test/learn_readline/history4.txt");
	return 0;
}
```
Here's the content of history.txt:
```
a
b
```
After build and run, as you can guess, history2.txt is same as
history.txt. But history3.txt and history4.txt content are:
```
a
b
a
b
```

Signed-off-by: Xiao Pan <[email protected]>
  • Loading branch information
flyxyz123 authored and Dushistov committed Aug 15, 2024
1 parent 49c8094 commit beebb0f
Showing 1 changed file with 1 addition and 2 deletions.
3 changes: 1 addition & 2 deletions src/libwrapper.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -415,10 +415,9 @@ search_result Library::process_phrase(const char *loc_str, IReadLine &io, bool f
colorize_output_ ? ESC_END : "");
}
int choise;
std::unique_ptr<IReadLine> choice_readline(create_readline_object());
for (;;) {
std::string str_choise;
choice_readline->read(_("Your choice[-1 to abort]: "), str_choise);
io.read(_("Your choice[-1 to abort]: "), str_choise);
sscanf(str_choise.c_str(), "%d", &choise);
if (choise >= 0 && choise < int(res_list.size())) {
sdcv_pager pager;
Expand Down

0 comments on commit beebb0f

Please sign in to comment.