On 05/16/2017 10:55 PM, John Ferlan wrote: > > > On 05/16/2017 10:03 AM, Michal Privoznik wrote: >> This function takes a FD and determines whether the current >> position is in data section or in a hole. In addition to that, >> it also determines how much bytes are there remaining till the >> current section ends. >> >> Signed-off-by: Michal Privoznik <mprivozn@xxxxxxxxxx> >> --- >> src/libvirt_private.syms | 1 + >> src/util/virfile.c | 82 +++++++++++++++++++ >> src/util/virfile.h | 4 + >> tests/virfiletest.c | 203 +++++++++++++++++++++++++++++++++++++++++++++++ >> 4 files changed, 290 insertions(+) >> >> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms >> index bbe283529..4102a002b 100644 >> --- a/src/libvirt_private.syms >> +++ b/src/libvirt_private.syms >> @@ -1628,6 +1628,7 @@ virFileGetHugepageSize; >> virFileGetMountReverseSubtree; >> virFileGetMountSubtree; >> virFileHasSuffix; >> +virFileInData; >> virFileIsAbsPath; >> virFileIsDir; >> virFileIsExecutable; >> diff --git a/src/util/virfile.c b/src/util/virfile.c >> index ea44a647c..5b10f9489 100644 >> --- a/src/util/virfile.c >> +++ b/src/util/virfile.c >> @@ -3793,6 +3793,88 @@ virFileComparePaths(const char *p1, const char *p2) >> cleanup: >> VIR_FREE(res1); >> VIR_FREE(res2); >> + >> + return ret; >> +} >> + >> + > > Still undocumented. > > I know it got discussed a few times... I guess the odd thing I find > about "long long" is that all the stream mgmt lengths/sizes, etc. are > size_t. You also only test for smaller values only. Just saying... That's true for areas where we need to address individual bytes in buffers, e.g. virStreamRecv & virStreamSend. When it comes to file offsets like in virStorageVolDownload and virStorageVolUpload we use ULL. > > Please just add the function description *and* why a long long is being > used here. Also a brief summary of what's being done and of course that > lseek @cleanup: How about this: +/** + * virFileInData: + * @fd: file to check + * @inData: true if current position in the @fd is in data section + * @length: amount of bytes until the end of the current section + * + * With sparse files not every extent has to be physically stored on + * the disk. This results in so called data or hole sections. This + * functions checks whether the current position in the file @fd is + * in a data section (@inData = 1) or in a hole (@inData = 0). Also, + * it sets @length to match the number of bytes remaining until the + * end of the current section. + * + * As a special case, there is an implicit hole at the end of any + * file. In this case, the function sets @inData = 0, @length = 0. + * + * Upon its return, the position in the @fd is left unchanged, i.e. + * despite this function lseek()-ing back and forth it always + * restores the original position in the file. + * + * NB, @length is type of long long because it corresponds to off_t + * the best. + * + * Returns 0 on success, + * -1 otherwise. + */ Michal -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
