1 files changed, 63 insertions, 0 deletions
diff --git a/modules/llvm.py b/modules/llvm.py
index 8d549fd..2625038 100644
--- a/modules/llvm.py
+++ b/modules/llvm.py
@@ -1,6 +1,8 @@
 import os
 import re
 
+from functools import partial
+
 from linaropy.git.worktree import Worktree
 
 
@@ -98,6 +100,10 @@ class LLVMSourceConfig(object):
         self.llvmSourceTree = Worktree(proj, sourcePath)
         self.subprojs = subprojs
 
+    def get_path(self):
+        """Get the path corresponding to this source config."""
+        return self.llvmSourceTree.repodir
+
     def get_enabled_subprojects(self):
         """Get a list of the subprojects enabled in this configuration."""
         enabled = []
@@ -263,6 +269,63 @@ class LLVMSourceConfig(object):
         worktree.clean(False)
 
 
+class LLVMBuildConfig(object):
+    """Class for managing an LLVM build directory.
+
+    It should know how to configure a build directory (with CMake) and how to
+    run a build command. The directory must already exist, but it may be empty.
+    """
+
+    def __init__(self, sourceConfig, buildDir=None):
+        """Create an LLVMBuildConfig."""
+        self.sourceConfig = sourceConfig
+        self.buildDir = buildDir
+
+    def cmake(self, commandConsumer, cmakeFlags, generator):
+        """
+        Generate the CMake command needed for configuring the build directory
+        with the given flags and generator, and pass it to the 'commandConsumer'.
+
+        The command will always explicitly enable or disable the build of
+        specific subprojects to mirror the source config. This is important
+        because projects can always be added or removed from the source config,
+        and CMake doesn't by default pick up the new situation (so we might end
+        up trying to build subprojects that were removed, or not build
+        subprojects that were added).
+
+        The 'commandConsumer' should have a 'consume' method taking two
+        parameters: the command to be consumed (in the form of a list) and the
+        directory where the command should be run. Any exceptions that may be
+        raised by that method should be handled by the calling code.
+        """
+        cmakeSubprojFlags = self.__get_subproj_flags()
+        command = ["cmake", "-G", generator] + cmakeSubprojFlags + \
+            cmakeFlags + [self.sourceConfig.get_path()]
+        commandConsumer.consume(command, self.buildDir)
+
+    def __get_subproj_flags(self):
+        """
+        Get the CMake flags needed to explicitly enable or disable the build of
+        each specific subproject, depending on whether it is enabled or disabled
+        in the source config.
+        """
+        def append_cmake_var(cmakeVars, subproj, enabled):
+            if subproj.cmake_var is None:
+                return
+
+            if enabled:
+                status = "ON"
+            else:
+                status = "OFF"
+            cmakeVars.append("-D{}={}".format(subproj.cmake_var, status))
+
+        cmakeSubprojFlags = []
+        self.sourceConfig.for_each_subproj(partial(append_cmake_var,
+                                                   cmakeSubprojFlags))
+
+        return cmakeSubprojFlags
+
+
 # FIXME: repo.pushToBranch doesn't work, because it doesn't handle remote
 # branches properly. Furthermore, there's no support for getting the remote URL,
 # so we need to resort to raw git commands. We may also consider moving the