Comments and more improvement. #3
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… whats happening.
| @@ -129,8 +143,8 @@ bool MapzenVectorTileJson::LoadTile(std::vector<glm::ivec3> tileCoords) { | |||
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| //timeout specification for select() call | |||
| //select() will unblock either when a fd is ready or tileout is reached | |||
| timeout.tv_sec = 0; | |||
| timeout.tv_usec = 100; | |||
| timeout.tv_sec = 1; //enough time for fd to be ready reading data... could be optimized. | |||
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Does this mean it waits 1 second? Most tiles should be done well before then (if they are performing well...).
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Ya. so select will either halt the thread for 1 second or continue if a file descriptor is ready.
So worst case if no tile url is responding it will timeout in 1 second... and try again .. I can remove the try again portion and return false ...
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Ah, sorry, so this is a timeOUT? If it hits the timeout and needs to retry, is there a retry limit? (3 is a good default rule of thumb)
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Ya right now it will keep on trying.. I will put a limit on that.
Which reminds me ... we should have a header with all such "MAGIC" number const/#define macros defined. What say @blair1618 and @patriciogonzalezvivo
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Updated |
| return false; | ||
| } | ||
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| //wait and repeat until curl has something to report to the kernel wrt file descriptors | ||
| // TODO: if no internet, then this gets stuck... put a timeout here. |
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added a very basic logic to timeout if fdset never sets a valid fdmax (can happen with super slow internet or no internet or service down)
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Cool - connectivity is something we will want to think carefully about across the library. Both on mobile generally and in NYC specifically, uneven connectivity is a common issue (bad coverage, subway, etc.). Also just requires a lot of real-world testing.
…ync between the producer (tile data being generated) and consumer (tiles being rendered). Can work on a producer-consumer sync when the time is right.
…ync between the producer (tile data being generated) and consumer (tiles being rendered). Can work on a producer-consumer sync when the time is right.
1. Implements libCurl multi interface with select() and file descriptor setting and error checking.
2. Implements relevant timeout:
2a. Timeout for not able to contact the service
2b. Timeout for not able to retrieve the data in 1 sec from the service.
3. Implements simple std::thread for fetching of tiles from service.
4. Implements CheckDataExists for DataSource class.
more logic to not do extra processing. A lot more comments to explain whats happening.