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Commite21db14

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Clarify the new Red-Black post-order traversal code a bit.

Coverity complained about the for(;;) loop, because it never actuallyiterated. It was used just to be able to use "break" to exit it early. Iagree with Coverity, that's a bit confusing, so refactor the code touse if-else instead.While we're at it, use a local variable to hold the "current" node. That'sshorter and clearer than referring to "iter->last_visited" all the time.

1 parent6591f42 commite21db14Copy full SHA for e21db14

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1 file changed

+24

-22

lines changed

src/backend/lib
- rbtree.c

1 file changed

+24

-22

lines changed

`‎src/backend/lib/rbtree.c`

Lines changed: 24 additions & 22 deletions

Original file line number	Diff line number	Diff line change
`@@ -781,27 +781,30 @@ static RBNode *`
`781`	`781`	`rb_inverted_iterator(RBTreeIterator*iter)`
`782`	`782`	`{`
`783`	`783`	`RBNode*came_from;`
	`784`	`+RBNode*current;`
	`785`	`+`
	`786`	`+current=iter->last_visited;`
`784`	`787`
`785`	`788`	`loop:`
`786`	`789`	`switch ((InvertedWalkNextStep)iter->next_step)`
`787`	`790`	`{`
`788`	`791`	`/* First call, begin from root */`
`789`	`792`	`caseNextStepBegin:`
`790`		`-iter->last_visited=iter->rb->root;`
	`793`	`+current=iter->rb->root;`
`791`	`794`	`iter->next_step=NextStepLeft;`
`792`	`795`	`gotoloop;`
`793`	`796`
`794`	`797`	`caseNextStepLeft:`
`795`		`-while (iter->last_visited->left!=RBNIL)`
`796`		`-iter->last_visited=iter->last_visited->left;`
	`798`	`+while (current->left!=RBNIL)`
	`799`	`+current=current->left;`
`797`	`800`
`798`	`801`	`iter->next_step=NextStepRight;`
`799`	`802`	`gotoloop;`
`800`	`803`
`801`	`804`	`caseNextStepRight:`
`802`		`-if (iter->last_visited->right!=RBNIL)`
	`805`	`+if (current->right!=RBNIL)`
`803`	`806`	`{`
`804`		`-iter->last_visited=iter->last_visited->right;`
	`807`	`+current=current->right;`
`805`	`808`	`iter->next_step=NextStepLeft;`
`806`	`809`	`gotoloop;`
`807`	`810`	`}`
`@@ -810,30 +813,29 @@ rb_inverted_iterator(RBTreeIterator *iter)`
`810`	`813`	`break;`
`811`	`814`
`812`	`815`	`caseNextStepUp:`
`813`		`-for (;;)`
	`816`	`+came_from=current;`
	`817`	`+current=current->parent;`
	`818`	`+if (current==NULL)`
	`819`	`+{`
	`820`	`+iter->is_over= true;`
	`821`	`+break;/* end of iteration */`
	`822`	`+}`
	`823`	`+elseif (came_from==current->right)`
	`824`	`+{`
	`825`	`+/* return current, then continue to go up */`
	`826`	`+break;`
	`827`	`+}`
	`828`	`+else`
`814`	`829`	`{`
`815`		`-came_from=iter->last_visited;`
`816`		`-iter->last_visited=iter->last_visited->parent;`
`817`		`-if (iter->last_visited==NULL)`
`818`		`-{`
`819`		`-iter->is_over= true;`
`820`		`-break;/* end of iteration */`
`821`		`-}`
`822`		`-`
`823`		`-if (came_from==iter->last_visited->right)`
`824`		`-{`
`825`		`-/* return current, then continue to go up */`
`826`		`-break;`
`827`		`-}`
`828`		`-`
`829`	`830`	`/* otherwise we came from the left */`
	`831`	`+Assert(came_from==current->left);`
`830`	`832`	`iter->next_step=NextStepRight;`
`831`	`833`	`gotoloop;`
`832`	`834`	`}`
`833`		`-break;`
`834`	`835`	`}`
`835`	`836`
`836`		`-returniter->last_visited;`
	`837`	`+iter->last_visited=current;`
	`838`	`+returncurrent;`
`837`	`839`	`}`
`838`	`840`
`839`	`841`	`/*`

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Commite21db14

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`‎src/backend/lib/rbtree.c`

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