Cache the results of is_exe_in_path.

Review Request #11823 — Created Sept. 27, 2021 and submitted

Information
chipx86
RBTools
master
Reviewers
rbtools 
is_exe_in_path() may be called multiple times with the same executable

name, particularly when running from unit tests. Since an executable is

unlikely to appear or disappear within the lifetime of a process run in

a way that impacts RBTools, it's not worth re-scanning the whole path

every time we need to know if an executable is available.


This change adds caching behavior to is_exe_in_path(). Now, a repeated

call with the same executable name (with or without a .exe file

extension) will return the prior cached result.
All unit tests pass.
Summary 
Cache the results of is_eze_in_path.
Description From Last Updated

Might be a little simpler as: if name not in _exe_in_path_cache: ... _exe_in_path_cache[name] = found return _exe_in_path_cache[name]

 daviddavid
david
david 
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      rbtools/utils/filesystem.py
      


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    Might be a little simpler as:
    

    

    if name not in _exe_in_path_cache:
    ...
    _exe_in_path_cache[name] = found

return _exe_in_path_cache[name]

    
  
    
 
    

 
    
  


    
 
    
 
      

  


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      This is a pretty common pattern when using a dictionary as a cache. You avoid the repeated lookups in the dictionary by assuming the key is present, and then only writing to the dictionary if not. Saves a dictionary lookup. This code isn't a bottleneck, but the pattern's a good one.
      

      Another option is I could switch to @lru_cache, but it's only in Python 3 (without depending on a backport for 2).
      
 
      

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      OK, sure.
      
 
      

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david




   

   







  

 



 

  


   

   

    
 
david


    
   


  

  

  



    




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    Ship It!
    
  
    
 
    

 
    
  


    
 
    
 
      

  

 
    


    

 
    

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david




   

   







  

 



 

  


   

   

    
 
david


    
   


  

  

  



    




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    Ship It!
    
  
    
 
    

 
    
  


    
 
    
 
      

  

 
    


    

 
    

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chipx86




   

   

  

 



 

  


   

   

    
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  Status:
  

  Closed (submitted)

  
 




 
Change Summary:

 
Pushed to master (dc70d35)





 


 










  

 









     

    

   

  

  

   
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