Support for searching for previous event in the Events Table

[bhufmann]

• Add a 'previous' button in the column search cells right beside the
  'next' button
• Use keyboard short-cut SHIFT+ENTER to search previous event

fixes #412

Signed-off-by: Bernd Hufmann Bernd.Hufmann@ericsson.com

[bhufmann]

@muddana-satish could you please review this change? The latest nightly build has the corresponding back-end code implementation.

https://download.eclipse.org/tracecompass.incubator/trace-server/rcp/

[ghost]

Looks good to me.

I don't know if we want to fix it in this but we no longer need the 'isFiltered' flag. Also we don't need additional information from the api like 'tags'.

[bhufmann]

I updated the patch according to the review comments.

I also noticed a general bug with the searching. The AgGrid keeps a cache of size maxBlocksInCachecacheBlockSize (in our case (5200)=1000), where each block of cacheBlockSize events are fetched from the back-end. These 5 blocks, however, are not necessarily consecutive blocks, it depends on user's navigation. In the search feature, where we do this.gridApi.forEachNode(...) to move to the next match, the whole cache is looped through. It could happen that the first matched event in the cache is not inside the current block and the table moves somewhere else in the table where the next matched event in the cache is found. I corrected that in this PR as well.

[PatrickTasse]

Some more suggestions perhaps for future enhancement:

• It should be possible to use Enter/Shift+Enter when the table itself has focus
• There should be a visual feedback while we are searching the next/previous index, not only when we are waiting to fill the table at the found index
• It should not lose current table selection if there is no found index