ichthyo/LUMIERA.clone
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Block-Flow: veryfy proper handling of extent reuse

Browse source 
- use a checksum to prove that ctor / dtor of "content" is not invoked
- let the usage of active extents "wrap around" so that the mem block is re-used
- verify that the same data is still there
This commit is contained in:
Fischlurch 2023-07-12 04:53:30 +02:00
parent 6409e0eb36
commit f5813a1f29
3 changed files with 102 additions and 5 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
src/vault/mem/extent-family.hpp
View file

@ -276,8 +276,9 @@ namespace mem {
REQUIRE (idx < extents_.size());
REQUIRE (activeSlotCnt() > 0);
return start_ <= idx
and idx < after_;
return isWrapped()? (start_ <= idx and idx < extents_.size())
or idx < after_
: (start_ <= idx and idx < after_);
}
Extent&

79
tests/vault/mem/extent-family-test.cpp
View file

@ -28,7 +28,8 @@
#include "lib/test/run.hpp"
#include "vault/mem/extent-family.hpp"
//#include "lib/time/timevalue.hpp"
//#include "lib/format-cout.hpp"
//#include "lib/format-cout.hpp"////////////////////TODO
#include "lib/test/diagnostic-output.hpp"
//#include "lib/util.hpp"
#include <utility>
@ -69,6 +70,7 @@ namespace test {
simpleUsage();
use_and_drop();
iteration();
reuseUnclean();
wrapAround();
}
@ -126,9 +128,9 @@ namespace test {
{
Extents extents{5};
Iter it = extents.begin();
CHECK (isnil (it));
CHECK (isnil (it)); // no extents provided yet
extents.openNew(2); // allocate two Extents
extents.openNew(2); // allot two extents for active use
CHECK (it);
CHECK (0 == it.getIndex());
@ -165,6 +167,77 @@ namespace test {
/** @test verify that neither constructors nor destructors are invoked
* automatically when discarding or re-using extents.
*/
void
reuseUnclean()
{
struct Probe
{
short val;
Probe() : val(1 + rand() % 1000) { }
~Probe() { val = 0; }
};
using SpecialExtents = ExtentFamily<Probe, 100>;
SpecialExtents spex{3};
spex.openNew(2);
CHECK ( 0 == watch(spex).first());
CHECK ( 2 == watch(spex).last());
// implant a new Probe object into each »slot« of the new extent
auto& extent = *spex.begin();
for (Probe& probe : extent)
new(&probe) Probe;
auto calcChecksum = [](SpecialExtents::Extent& extent) -> size_t
{
size_t sum{0};
for (Probe& probe : extent)
sum += probe.val;
return sum;
};
size_t checksum = calcChecksum (*spex.begin());
// discard first extent, i.e. mark it as unused
// while the underlying memory block remains allocated
// and data within this block is not touched
spex.dropOld(1);
CHECK ( 1 == watch(spex).first());
CHECK ( 2 == watch(spex).last());
// the »begin« (i.e. the first active extent is now another memory block
CHECK (not isSameObject (extent, *spex.begin()));
size_t checkSecond = calcChecksum (*spex.begin());
CHECK (checkSecond != checksum);
// but the random data generated above still sits in the original (first) memory block
CHECK (checksum == calcChecksum (extent));
// now let the actively allotted extents "wrap around"...
spex.dropOld(1);
CHECK ( 2 == watch(spex).first());
CHECK ( 2 == watch(spex).last());
spex.openNew(2);
CHECK ( 2 == watch(spex).first());
CHECK ( 1 == watch(spex).last());
auto iter = spex.begin();
CHECK ( 2 == iter.getIndex());
++iter;
CHECK ( 0 == iter.getIndex());
CHECK (isSameObject(*iter, extent));
// and during all those allotting and dropping, data in the memory block was not touched,
// which also proves that constructors or destructors of the nominal "content" are not invoked
CHECK (checksum == calcChecksum (extent));
}
/** @test verify in detail how iteration wraps around to also reuse
* previously dropped extents, possibly rearranging the internal
* management-vector to allow growing new extents at the end.

23
wiki/thinkPad.ichthyo.mm
View file

@ -78795,6 +78795,29 @@ Date:&#160;&#160;&#160;Thu Apr 20 18:53:17 2023 +0200<br/>
<icon BUILTIN="button_ok"/>
</node>
</node>
<node COLOR="#338800" CREATED="1689130091868" ID="ID_1078761905" MODIFIED="1689130098882" TEXT="reuseUnclean">
<icon BUILTIN="button_ok"/>
<node COLOR="#338800" CREATED="1689130101082" ID="ID_602242804" MODIFIED="1689130136363" TEXT="spezielles Testobjekt">
<icon BUILTIN="button_ok"/>
<node CREATED="1689130113232" ID="ID_1068658762" MODIFIED="1689130120747" TEXT="ctor belegt ein Feld mit Random-Werten"/>
<node CREATED="1689130121418" ID="ID_745826511" MODIFIED="1689130134369" TEXT="dtor setzt das Feld auf 0 zur&#xfc;ck"/>
</node>
<node COLOR="#338800" CREATED="1689130137965" ID="ID_856848414" MODIFIED="1689130148696" TEXT="einen gr&#xf6;&#xdf;eren Block damit f&#xfc;llen">
<icon BUILTIN="button_ok"/>
</node>
<node COLOR="#338800" CREATED="1689130149324" ID="ID_102457936" MODIFIED="1689130158266" TEXT="Pr&#xfc;fsumme &#xfc;ber alle diese Random-Zahlen">
<icon BUILTIN="button_ok"/>
</node>
<node COLOR="#338800" CREATED="1689130159170" ID="ID_1023088377" MODIFIED="1689130180869" TEXT="dann die aktiven Extents &#x201e;rotieren&#x201c;">
<icon BUILTIN="button_ok"/>
</node>
<node COLOR="#435e98" CREATED="1689130236679" ID="ID_1843146082" MODIFIED="1689130275626" TEXT="der Block war zwischenzeitlich verworfen und wird nun neu belegt">
<icon BUILTIN="info"/>
</node>
<node COLOR="#338800" CREATED="1689130190886" ID="ID_1953109784" MODIFIED="1689130271958" TEXT="verifizieren (Pr&#xfc;fsummen) da&#xdf; die Daten im Block unver&#xe4;ndert sind">
<icon BUILTIN="button_ok"/>
</node>
</node>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1688863046274" ID="ID_121256425" MODIFIED="1688863054657" TEXT="iteration mit wrap-around">
<icon BUILTIN="flag-yellow"/>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1688863075348" ID="ID_619946525" MODIFIED="1688863105883" TEXT="Iteration in Normal-Stellung alloziert am Ende">