Mercurial > public > mercurial-scm > hg
comparison mercurial/util.py @ 30437:64d7275445d0
util: expose an "available" API on compression engines
When the zstd compression engine is introduced, it won't work in all
installations, namely pure Python installs. So, we need a mechanism to
declare whether a compression engine is available. We don't want to
conditionally register the compression engine because it is sometimes
useful to know when a compression engine name or encountered data is
valid but just not available versus unknown.
| author | Gregory Szorc <gregory.szorc@gmail.com> |
|---|---|
| date | Thu, 10 Nov 2016 23:03:48 -0800 |
| parents | 1156ec81f709 |
| children | 90933e4e44fd |
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| 30436:788ea4ac4388 | 30437:64d7275445d0 |
|---|---|
| 3045 | 3045 |
| 3046 This method must be implemented. | 3046 This method must be implemented. |
| 3047 """ | 3047 """ |
| 3048 raise NotImplementedError() | 3048 raise NotImplementedError() |
| 3049 | 3049 |
| 3050 def available(self): | |
| 3051 """Whether the compression engine is available. | |
| 3052 | |
| 3053 The intent of this method is to allow optional compression engines | |
| 3054 that may not be available in all installations (such as engines relying | |
| 3055 on C extensions that may not be present). | |
| 3056 """ | |
| 3057 return True | |
| 3058 | |
| 3050 def bundletype(self): | 3059 def bundletype(self): |
| 3051 """Describes bundle identifiers for this engine. | 3060 """Describes bundle identifiers for this engine. |
| 3052 | 3061 |
| 3053 If this compression engine isn't supported for bundles, returns None. | 3062 If this compression engine isn't supported for bundles, returns None. |
| 3054 | 3063 |