[libcamera-devel] [PATCH v4 1/3] meson: Shared Object version handling

[Kieran Bingham]

The libcamera project is not yet ready to declare ABI nor API stability,
but it will benefit the community to be able to provide more regular
release cycles to determine 'versioned' points of history.

Ideally, these releases will be made at any ABI breakage, but can be
made at arbitary time based points along the way.

To support releases which may not be ABI stable, declare the soversion
of both the libcamera and libcamera-base library to be dependant upon
both the major minor and patch component of the project version.

As part of this, introduce a new 'Versions' summary section to highlight
the different version components that may become apparent within any
given build.

Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

---

v4:
 - Use EXCLUDE_SYMLINKS
 - Reduce redundant information from Versions summary
 - -nvm appended when the sources do not match the project version.
 - Fixed the update of the libcamera source version from the project
   version in event of mismatch

v3:
 - fix typo
 - Use libcamera_version directly for SONAME.
 - Fix ordering of EXCLUDE_PATTERNS
 - Use meson.project_version() in the event the git versions
   are incorrect.
 - No need to present libcamera_version anymore
   - Guaranteed to be the same as 'project_version'

 Documentation/Doxyfile.in      |  2 ++
 meson.build                    | 32 ++++++++++++++++++++++++++++++++
 src/libcamera/base/meson.build |  1 +
 src/libcamera/meson.build      |  1 +
 4 files changed, 36 insertions(+)

diff --git a/Documentation/Doxyfile.in b/Documentation/Doxyfile.in
index 88dfcddaebf6..e4f0cd426d39 100644
--- a/Documentation/Doxyfile.in
+++ b/Documentation/Doxyfile.in
@@ -66,6 +66,8 @@ EXCLUDE_SYMBOLS        = libcamera::BoundMethodArgs \
                          *::details \
                          std::*
 
+EXCLUDE_SYMLINKS       = YES
+
 HTML_OUTPUT            = api-html
 
 GENERATE_LATEX         = NO
diff --git a/meson.build b/meson.build
index 2c6173b4f97e..9b0966cb04c9 100644
--- a/meson.build
+++ b/meson.build
@@ -26,6 +26,38 @@ endif
 
 libcamera_version = libcamera_git_version.split('+')[0]
 
+# A shallow clone, or a clone without a reachable tag equivalent to the
+# meson.project_version() could leave the project in a mis-described state.
+# Produce a warning in this event, and fix to a best effort.
+if libcamera_version != meson.project_version()
+    warning('The sources disagree about the version: '
+            + libcamera_version + ' != ' + meson.project_version())
+
+    summary({'libcamera git version' : libcamera_git_version,
+             'Source version match' : false,
+            },
+            bool_yn : true, section : 'Versions')
+
+    libcamera_git_version = libcamera_git_version.replace(libcamera_version,
+                                                          meson.project_version())
+    libcamera_version = meson.project_version()
+
+    # Append a marker to show we have modified this version string
+    libcamera_git_version += '-nvm'
+endif
+
+# Until we make ABI compatible releases, the full libcamera version is used as
+# the soname. No ABI/API compatibility is guaranteed between releases. (x.x.x)
+#
+# When automatic ABI based detection is used to increment the version, this
+# will bump the minor number. (x.x)
+#
+# When we declare a stable ABI/API we will provide a 1.0 release and the
+# soversion at that point will be the 'major' release value. (x)
+libcamera_soversion = libcamera_version
+
+summary({ 'Sources': libcamera_git_version, }, section : 'Versions')
+
 # This script generates the .tarball-version file on a 'meson dist' command.
 meson.add_dist_script('utils/run-dist.sh')
 
diff --git a/src/libcamera/base/meson.build b/src/libcamera/base/meson.build
index 7a75914ab2a8..7a7fd7e4ca87 100644
--- a/src/libcamera/base/meson.build
+++ b/src/libcamera/base/meson.build
@@ -51,6 +51,7 @@ libcamera_base_args = [ '-DLIBCAMERA_BASE_PRIVATE' ]
 libcamera_base_lib = shared_library('libcamera-base',
                                     [libcamera_base_sources, libcamera_base_headers],
                                     version : libcamera_version,
+                                    soversion : libcamera_soversion,
                                     name_prefix : '',
                                     install : true,
                                     cpp_args : libcamera_base_args,
diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
index 7fcbb2ddc9e7..5f39d2e2c60a 100644
--- a/src/libcamera/meson.build
+++ b/src/libcamera/meson.build
@@ -161,6 +161,7 @@ libcamera_deps = [
 libcamera = shared_library('libcamera',
                            libcamera_sources,
                            version : libcamera_version,
+                           soversion : libcamera_soversion,
                            name_prefix : '',
                            install : true,
                            include_directories : includes,
-- 
2.34.1