On 03/06/2017 05:04 AM, Daniel P. Berrange wrote:
On Mon, Mar 06, 2017 at 10:21:28AM +0100, Bjoern Walk wrote:
Daniel P. Berrange <berrange@xxxxxxxxxx> [2017-03-03, 10:50AM +0100]:
This documents the preferred conventions for naming files,
structs, enums, typedefs and functions.
Signed-off-by: Daniel P. Berrange <berrange@xxxxxxxxxx>
---
HACKING | 71 ++++++++++++++++++++++++++++++++++++++++++++
docs/hacking.html.in | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++
docs/hacking2.xsl | 4 +++
3 files changed, 158 insertions(+)
diff --git a/HACKING b/HACKING
index fff003b..16be5cf 100644
--- a/HACKING
+++ b/HACKING
@@ -239,6 +239,77 @@ on the subject, on Richard Jones' guide to working with open source projects
<http://people.redhat.com/rjones/how-to-supply-code-to-open-source-projects/>.
+Naming conventions
+==================
+When reading libvirt code, a number of different naming conventions will be
+evident due to various changes in thinking over the course of the project's
+lifetime. The conventions documented below should be followed when creating
+any entirely new files in libvirt. When working on existing files, while it is
+desirable to apply these conventions, keeping a consistent style with existing
+code in that particular file is generally more important. The overall guiding
+rule is that every file, enum, struct, function, and typedef name must have a
+'vir' or 'VIR' prefix. All local scope variable names are exempt, and global
+variables are exempt, unless exported in a header file.
+
+*File names*
+
+File naming varies depending on the subdirectory. The preferred style is to
+have a 'vir' prefix, followed by a name which matches the name of the
+functions / objects inside the file. For example, a file containing an object
+'virHashtable' is stored in files 'virhashtable.c' and 'virhashtable.h'.
+Sometimes, methods which would otherwise be declared 'static' need to be
+exported for use by a test suite. For this purpose a second header file should
+be added with a suffix of 'priv'. e.g. 'virhashtablepriv.h'. USe of
+underscores in file names is discouraged when using the 'vir' prefix style.
+The 'vir' prefix naming applies to src/util, src/rpc and tests/ directories.
+Most other directories do not follow this convention.
+
+
+
+*Enum type & field names*
+
+All enums should have a 'vir' prefix in their typedef name, and each following
+word should have its first letter in uppercase. The enum name should match the
+typedef name with a leading underscore. The enum member names should be in all
+uppercase, and use an underscore to separate each word. The enum member name
+prefix should match the enum typedef name.
+
+ typedef enum _virSocketType virSocketType;
+ enum _virSocketType {
+ VIR_SOCKET_TYPE_IPV4,
+ VIR_SOCKET_TYPE_IPV6,
+ };
+
+
+*Struct type names*
+
+All structs should have a 'vir' prefix in their typedef name, and each
+following word should have its first letter in uppercase. The struct name
+should be the same as the typedef name with a leading underscore. A second
+typedef should be given for a pointer to the struct with a 'Ptr' suffix.
+
+ typedef struct _virHashTable virHashTable;
+ typedef virHashTable *virHashTablePtr;
+ struct _virHashTable {
+ ...
+ };
+
I personally would prefer this style:
typedef struct _virHashTable {
...
} virHashTable, *virHashTablePtr;
This is done for example in src/conf/device_conf.h. Subjectively, it is
much easier to read, but objectively, it is more concise and enhances
discoverability. For example, in src/conf/domain_conf.h the typedef are
at the beginning of the file separated from the definition of the
struct. If I want to look up a virDomainDiskDefPtr it requires two
jumps.
We should change device_conf.h really - it is different from pretty much
everywhere else in the libvirt codebase.
There are others too. I've always disliked the separate typedefs and
extra _virBlah struct name, so quite awhile back I posted some patches
that used the more compact style in new struct definitions as a way of
suggesting that we use that instead, and they passed review. So I did
several more that way, and those passed as well (although I do remember
one dissenting opinion for one patch).
But if we're going to formalize struct definitions in a coding standards
document, then I'm willing to throw in the towel - to avoid leading
unsuspecting copy-pasters in the wrong direction, I just sent a patch
that changes all "compact format" struct definitions to the more verbose
format in the document.
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