cmake: Add aom_version.h generation.

BUG=https://bugs.chromium.org/p/aomedia/issues/detail?id=76

Change-Id: I9778eaa1dd67d36bae7953cbd8cbcd893f0aefac

build/cmake/aom_configure.cmake

@@ -117,26 +117,28 @@ set(CONFIG_BITSTREAM_DEBUG 0)
 set(CONFIG_TILE_GROUPS 0)
 set(CONFIG_EC_ADAPT 0)
 
-# TODO(tomfinegan): consume trailing whitespace after configure_file().
+# TODO(tomfinegan): consume trailing whitespace after configure_file() when
+# target platform check produces empty INLINE and RESTRICT values (aka empty
+# values require special casing).
 configure_file("${AOM_ROOT}/build/cmake/aom_config.h.cmake"
                "${CMAKE_CURRENT_BINARY_DIR}/aom_config.h")
 
 # Read the current git hash.
 find_package(Git)
+set(AOM_GIT_DESCRIPTION)
+set(AOM_GIT_HASH)
 if (GIT_FOUND)
-  # TODO(tomfinegan): Make this smart enough to write a proper version string
-  # when in a repo that is on a label and clean.
-  # TODO(tomfinegan): In addition to the one above, also make this a custom
-  # build rule so users don't have to re-run cmake to create accurately
-  # versioned cmake builds.
+  # TODO(tomfinegan): Add build rule so users don't have to re-run cmake to
+  # create accurately versioned cmake builds.
   execute_process(COMMAND ${GIT_EXECUTABLE}
                   --git-dir=${AOM_ROOT}/.git rev-parse HEAD
                   OUTPUT_VARIABLE AOM_GIT_HASH)
+  execute_process(COMMAND ${GIT_EXECUTABLE} --git-dir=${AOM_ROOT}/.git describe
+                  OUTPUT_VARIABLE AOM_GIT_DESCRIPTION ERROR_QUIET)
   # Consume the newline at the end of the git output.
-  string(STRIP ${AOM_GIT_HASH} AOM_GIT_HASH)
-else ()
-  set(AOM_GIT_HASH)
-endIf ()
+  string(STRIP "${AOM_GIT_HASH}" AOM_GIT_HASH)
+  string(STRIP "${AOM_GIT_DESCRIPTION}" AOM_GIT_DESCRIPTION)
+endif ()
 
 # TODO(tomfinegan): An alternative to dumping the configure command line to
 # aom_config.c is needed in cmake. Normal cmake generation runs do not make the
@@ -149,4 +151,19 @@ endIf ()
 # information available.
 set(AOM_CMAKE_CONFIG "cmake")
 configure_file("${AOM_ROOT}/build/cmake/aom_config.c.cmake"
-               "${CMAKE_CURRENT_BINARY_DIR}/aom_config.c")
+               "${AOM_CONFIG_DIR}/aom_config.c")
+
+# Find Perl.
+find_package(Perl)
+if (NOT PERL_FOUND)
+  message(FATAL_ERROR "Perl is required to build libaom.")
+endif ()
+
+# Generate aom_version.h.
+if ("${AOM_GIT_DESCRIPTION}" STREQUAL "")
+  set(AOM_GIT_DESCRIPTION "${AOM_ROOT}/CHANGELOG")
+endif ()
+execute_process(
+  COMMAND ${PERL_EXECUTABLE} "${AOM_ROOT}/build/cmake/aom_version.pl"
+  --version_data=${AOM_GIT_DESCRIPTION}
+  --version_filename=${AOM_CONFIG_DIR}/aom_version.h)

build/cmake/aom_version.pl

+#!/usr/bin/env perl
+##
+## Copyright (c) 2016, Alliance for Open Media. All rights reserved
+##
+## This source code is subject to the terms of the BSD 2 Clause License and
+## the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+## was not distributed with this source code in the LICENSE file, you can
+## obtain it at www.aomedia.org/license/software. If the Alliance for Open
+## Media Patent License 1.0 was not distributed with this source code in the
+## PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+##
+use strict;
+use warnings;
+use 5.010;
+use Getopt::Long;
+
+my $version_data;
+my $version_filename;
+GetOptions('version_data=s' => \$version_data,
+           'version_filename=s' => \$version_filename) or
+  die("Invalid arg(s): $!");
+
+if (!defined $version_data || length($version_data) == 0 ||
+    !defined $version_filename || length($version_filename) == 0) {
+  die("--version_data and --version_filename are required.");
+}
+
+# Determine if $version_data is a filename or a git tag/description.
+my $version_string;
+if (-r $version_data) {
+  # $version_data is the path to the CHANGELOG. Parse the most recent version.
+  my $changelog_filename = $version_data;
+  open(my $changelog_file, '<', $changelog_filename) or
+    die("Unable to open CHANGELOG @ $changelog_filename: $!.");
+
+  while (my $line = <$changelog_file>) {
+    my @split_line = split(" ", $line, 3);
+    next if @split_line < 2;
+    $version_string = $split_line[1];
+    last if substr($version_string, 0, 1) eq "v";
+  }
+  close($changelog_file);
+} else {
+  # $version_data is either a tag name or a full git description, one of:
+  # tagName OR tagName-commitsSinceTag-shortCommitHash
+  # In either case we want the first element of the array returned by split.
+  $version_string = (split("-", $version_data))[0];
+}
+
+if (substr($version_string, 0, 1) eq "v") {
+  $version_string = substr($version_string, 1);
+}
+
+my @version_components = split('\.', $version_string, 4);
+my $version_major = $version_components[0];
+my $version_minor = $version_components[1];
+my $version_patch = $version_components[2];
+
+my $version_extra = "";
+if (@version_components > 3) {
+  $version_extra = $version_components[3];
+}
+
+open(my $version_file, '>', $version_filename) or
+  die("Cannot open $version_filename: $!");
+
+my $version_packed = "((VERSION_MAJOR<<16)|(VERSION_MINOR<<8)|(VERSION_PATCH))";
+my $year = (localtime)[5] + 1900;
+my $lic_block = << "EOF";
+/*
+ * Copyright (c) $year, Alliance for Open Media. All rights reserved
+ *
+ * This source code is subject to the terms of the BSD 2 Clause License and
+ * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+ * was not distributed with this source code in the LICENSE file, you can
+ * obtain it at www.aomedia.org/license/software. If the Alliance for Open
+ * Media Patent License 1.0 was not distributed with this source code in the
+ * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+ */
+EOF
+
+select $version_file;
+print << "EOF";
+$lic_block
+#define VERSION_MAJOR $version_major
+#define VERSION_MINOR $version_minor
+#define VERSION_PATCH $version_patch
+#define VERSION_EXTRA \"$version_extra\"
+#define VERSION_PACKED $version_packed
+#define VERSION_STRING_NOSP \"v$version_string\"
+#define VERSION_STRING \" v$version_string\"
+EOF
+close($version_file);