[#220] Support environment variables in clangd options

Author: ddscharfe

bundles/org.eclipse.cdt.lsp.clangd/META-INF/MANIFEST.MF

@@ -29,9 +29,10 @@ Require-Bundle: org.eclipse.cdt.lsp;bundle-version="0.0.0",
  org.eclipse.ui.editors;bundle-version="0.0.0",
  org.eclipse.ui.ide;bundle-version="0.0.0",
  org.eclipse.ui.workbench;bundle-version="0.0.0",
- org.eclipse.ui.workbench.texteditor;bundle-version="0.0.0"
-Bundle-Activator: org.eclipse.cdt.lsp.internal.clangd.editor.ClangdPlugin
+ org.eclipse.ui.workbench.texteditor;bundle-version="0.0.0",
+ org.eclipse.core.variables
 Service-Component: OSGI-INF/org.eclipse.cdt.lsp.clangd.BuiltinClangdOptionsDefaults.xml,
  OSGI-INF/org.eclipse.cdt.lsp.internal.clangd.ClangdConfigurationAccess.xml,
  OSGI-INF/org.eclipse.cdt.lsp.internal.clangd.ClangdFallbackManager.xml,
  OSGI-INF/org.eclipse.cdt.lsp.internal.clangd.ClangdMetadataDefaults.xml
+Bundle-Activator: org.eclipse.cdt.lsp.internal.clangd.editor.ClangdPlugin

bundles/org.eclipse.cdt.lsp.clangd/src/org/eclipse/cdt/lsp/internal/clangd/ClangdLanguageServerProvider.java

@@ -19,14 +19,17 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
+import java.util.stream.Collectors;
 
 import org.eclipse.cdt.lsp.clangd.ClangdConfiguration;
 import org.eclipse.cdt.lsp.clangd.ClangdFallbackFlags;
 import org.eclipse.cdt.lsp.editor.Configuration;
 import org.eclipse.cdt.lsp.editor.LanguageServerEnable;
 import org.eclipse.cdt.lsp.server.ICLanguageServerProvider;
 import org.eclipse.core.resources.IProject;
+import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.ServiceCaller;
+import org.eclipse.core.variables.VariablesPlugin;
 
 public final class ClangdLanguageServerProvider implements ICLanguageServerProvider {
 
@@ -47,10 +50,19 @@ public Object getInitializationOptions(URI rootUri) {
 	@Override
 	public List<String> getCommands(URI rootUri) {
 		List<String> result = new ArrayList<>();
-		configuration.call(c -> result.addAll(c.commands(rootUri)));
+		configuration.call(c -> result.addAll(c.commands(rootUri).stream()
+				.map(ClangdLanguageServerProvider::resolveVariables).collect(Collectors.toList())));
 		return result;
 	}
 
+	private static String resolveVariables(String cmd) {
+		try {
+			return VariablesPlugin.getDefault().getStringVariableManager().performStringSubstitution(cmd);
+		} catch (CoreException e) {
+			return cmd;
+		}
+	}
+
 	@Override
 	public boolean isEnabledFor(IProject project) {
 		boolean[] enabled = new boolean[1];