Handle variety scenarios that a mtable parser enters an infinite loop #1719
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By nature, a mtable regex parser can enter an infinite loop. This change
is for avoiding entering infinite loop resulted from a simple
programming mistake.
Following conditions for entering infinite loop are satisfied:
+ matching the pattern succeeds,
+ the next table is not given, and
+ The input file pos doesn't advance.
Following parser for an empty file satisfies the condition:
--langdef=FOO
--_tabledef-FOO=main
--kinddef-FOO=e,eof,the end of file
--_mtable-regex-FOO=main//eof/e/
This commit advances the input pos forcefully when detecting the
conditions are met.
Signed-off-by: Masatake YAMATO <yamato@redhat.com>
The combination of an input file and an empty regex pattern (//)
caused an error with the following message:
ctags: could not read tag line from ./input.foo at line 1
This commit accepts the combination.
Signed-off-by: Masatake YAMATO <yamato@redhat.com>
When ctags reaches the end of the input file, ctags runs mtable and mline parsers. Reaching the end can happens twice. As the result ctags may run a mtable (or mline) parser twice for the same input file. This is a bug. See createTagsWithFallback1. It calls createTagsForFile. During running this function, reaching the end can happens once. After calling createTagsForFile, createTagsWithFallback1 calls readLineFromInputFile in a loop. Reaching the end can happens once again. To avoid the bug, we need a mechanism to limit running the parsers for the same input only once. This commit uses File.allLines as a flag. ctags verifies File.allLines is not NULL before running the parsers. If it is NULL, skip the running. Signed-off-by: Masatake YAMATO <yamato@redhat.com>
…empty pattern. This case is for tests the following commits: * mtable-lregex: avoid entering infinite loop when reaching EOF * mtable-lregex: accept empty output pattern in tags file * mtable|mline-lregex avoid running a parser twice for the same input file Signed-off-by: Masatake YAMATO <yamato@redhat.com>
By nature, a mtable regex parser can enter an infinite loop. This change is for avoiding entering infinite loop resulted from a simple programming mistake. This commit limits the depth of stack where tables are pushed. Signed-off-by: Masatake YAMATO <yamato@redhat.com>
…n so long time By nature, a mtable regex parser can enter an infinite loop. This change is for avoiding entering infinite loop resulted from a simple programming mistake. When a parser doesn't consume an input stream so long time, we can assume it enters an infinite loop. In such cases, ctags stops running the parser for the input with warning. This commit deals with the following case: A. a parser doesn't advance the input position repeatedly, and B. its table stack doesn't grow so deep but it switches the tables. Signed-off-by: Masatake YAMATO <yamato@redhat.com>
Signed-off-by: Masatake YAMATO <yamato@redhat.com>
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Pattern matching should be done with sliding the input position. The advance of the sliding being zero means a parser entering an infinite loop. With this commit, the mline lregex meta parser checks the advance everytime matching is successful; if the advance is zero, the meta parser warns it. Signed-off-by: Masatake YAMATO <yamato@redhat.com>
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( I have to do the same overhauling the mline meta parser.)