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Specify the behavior for dealing with already compressed files more |
| 2 |
strictly, by requiring them not to be compressed twice if compressed |
| 3 |
using the same format already. This replaces the previous vague |
| 4 |
statement of 'behaving sensibly if already compressed'. This statement |
| 5 |
had a number of problems. |
| 6 |
|
| 7 |
Firstly, it was entirely vague on what 'sensible behavior' is. Most |
| 8 |
of the developers seemed to presume it means decompressing the file |
| 9 |
and compressing it again. However, without a clearly defined list |
| 10 |
of compression formats to support, this is impossible to implement |
| 11 |
properly. |
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|
| 13 |
Secondly, different package managers disagreed on the implementation. |
| 14 |
For example, Portage recompressed the file, with the implementation |
| 15 |
originally supporting .Z, .gz and .bz2, and later gaining support for |
| 16 |
.lzma and .xz (independently of EAPI support for those formats). |
| 17 |
PkgCore and Paludis never supported controllable compression, so they |
| 18 |
always installed the files in original format. |
| 19 |
|
| 20 |
The new wording aims to be more precise and strict while preserving |
| 21 |
the spirit of the original and allowing the behavior currently exhibited |
| 22 |
by the package manager implementations. Most notably, it accounts for |
| 23 |
the possibility of the same file being iterated over by the compression |
| 24 |
routine twice. |
| 25 |
|
| 26 |
It does not require the package manager to recognize arbitrary |
| 27 |
compressed file formats, making the current implementations compliant |
| 28 |
with it. At the same time, it implies that the developers need to |
| 29 |
account for the package manager not handling the particular compressed |
| 30 |
file format used upstream, and appropriately needing to decompress |
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the file in order to fully respect controllable compression. |
| 32 |
--- |
| 33 |
pkg-mgr-commands.tex | 6 +++--- |
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1 file changed, 3 insertions(+), 3 deletions(-) |
| 35 |
|
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diff --git a/pkg-mgr-commands.tex b/pkg-mgr-commands.tex |
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index 1e414d4..9c07a0f 100644 |
| 38 |
--- a/pkg-mgr-commands.tex |
| 39 |
+++ b/pkg-mgr-commands.tex |
| 40 |
@@ -774,9 +774,9 @@ times or if an item is a symlink. |
| 41 |
|
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\featurelabel{docompress} In EAPIs listed in table~\ref{tab:staging-area-commands} as supporting |
| 43 |
controllable compression, the package manager may optionally compress a subset of the files under |
| 44 |
-the \t{ED} directory. The package manager shall ensure that its compression mechanisms behave |
| 45 |
-sensibly even if a file is already compressed. For compression, the initial values of the two lists |
| 46 |
-are as follows: |
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+the \t{ED} directory. The package manager shall ensure that its compression mechanisms do not |
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+compress the file twice if it is already compressed using the same compressed file format. |
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+For compression, the initial values of the two lists are as follows: |
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|
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\begin{compactitem} |
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\item The inclusion list contains \t{/usr/share/doc}, \t{/usr/share/info} and \t{/usr/share/man}. |
| 53 |
-- |
| 54 |
2.19.0 |
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