improve CCDB discovery

Author: rtbo

source/served/extension.d

@@ -21,7 +21,7 @@ import std.format : format;
 import std.functional : toDelegate;
 import std.meta : AliasSeq;
 import std.path : baseName, buildNormalizedPath, buildPath, chainPath, dirName,
-	globMatch, relativePath;
+	dirSeparator, globMatch, relativePath;
 import std.string : join;
 
 import io = std.stdio;
@@ -696,17 +696,31 @@ void delayedProjectActivation(WorkspaceD.Instance instance, string workspaceRoot
 
 string discoverCcdb(string root)
 {
+	import std.algorithm : count, sort;
+
 	trace("discovering CCDB in ", root);
 
 	if (fs.exists(chainPath(root, "compile_commands.json")))
 		return buildNormalizedPath(root, "compile_commands.json");
 
-	foreach (entry; tryDirEntries(root, "compile_commands.json", fs.SpanMode.breadth))
-	{
-		return buildNormalizedPath(entry.name);
-	}
+	string[] dbs = tryDirEntries(root, "compile_commands.json", fs.SpanMode.breadth)
+		.map!(e => buildNormalizedPath(e.name))
+		.array;
+
+	// using in priority:
+	//  - those which have fewer directory depth
+	//  - lexical order
+	dbs.sort!((a, b) {
+		const depthA = count(a, dirSeparator);
+		const depthB = count(b, dirSeparator);
+		if (depthA != depthB)
+			return depthA < depthB;
+		return a < b;
+	});
+
+	tracef("discovered following CCDB:%-(\n - %s%)", dbs);
 
-	return null;
+	return dbs.length ? dbs[0] : null;
 }
 
 void didLoadDubProject()