[DB] Move header -> source function to DB.

Summary:
Implement heuristics to get from corresponding source files for header files.
We already had initial implementation for CaptureCompilationDatabase - moved it and extended it
to handle C/C++/objC/objC++

Reviewed By: jberdine

Differential Revision: D4231864

fbshipit-source-id: 4516287

infer/src/base/DB.ml

@@ -131,6 +131,30 @@ let source_file_is_cpp_model file =
       string_is_prefix Config.relative_cpp_models_dir path
   | _ -> false
 
+let source_file_exists_cache = Hashtbl.create 256
+
+let source_file_path_exists abs_path =
+  try Hashtbl.find source_file_exists_cache abs_path
+  with Not_found ->
+    let result = Sys.file_exists  abs_path in
+    Hashtbl.add source_file_exists_cache abs_path result;
+    result
+
+
+let source_file_of_header header_file =
+  let abs_path = source_file_to_abs_path header_file in
+  let source_file_exts = ["c"; "cc"; "cpp"; "cxx"; "m"; "mm"] in
+  let header_file_exts = ["h"; "hh"; "hpp"; "hxx"] in
+  let file_no_ext, ext_opt = Core.Std.Filename.split_extension abs_path in
+  let file_opt = match ext_opt with
+    | Some ext when IList.mem string_equal ext header_file_exts -> (
+        let possible_files = IList.map (fun ext -> file_no_ext ^ "." ^ ext) source_file_exts in
+        try Some (IList.find source_file_path_exists possible_files)
+        with Not_found -> None
+      )
+    | _ -> None in
+  Option.map source_file_from_abs_path file_opt
+
 (** {2 Source Dirs} *)
 
 (** source directory: the directory inside the results dir corresponding to a source file *)

infer/src/base/DB.mli

@@ -120,6 +120,10 @@ val source_file_is_infer_model : source_file -> bool
 (** Returns true if the file is a C++ model *)
 val source_file_is_cpp_model : source_file -> bool
 
+(** Return approximate source file corresponding to the parameter if it's header file and
+    file exists. returns None otherwise *)
+val source_file_of_header : source_file -> source_file option
+
 (** {2 Source Dirs} *)
 
 (** source directory: the directory inside the results dir corresponding to a source file *)

infer/src/integration/CaptureCompilationDatabase.ml

@@ -17,18 +17,7 @@ let capture_text =
   else "translating"
 
 let replace_header_file_with_source_file file_path =
-  let file_path = DB.source_file_to_abs_path file_path in
-  let possible_file_replacements file_path =
-    IList.map (fun suffix -> (Filename.chop_extension file_path) ^ suffix ) [".m"; ".mm"] in
-  let file =
-    if Filename.check_suffix file_path ".h" || Filename.check_suffix file_path ".hh" then
-      try
-        IList.find Sys.file_exists (possible_file_replacements file_path)
-      with Not_found ->
-        Logging.out "Couldn't find any replacement source file for file %s " file_path;
-        file_path
-    else file_path in
-  DB.source_file_from_abs_path file
+  Option.default file_path (DB.source_file_of_header file_path)
 
 (** Read the files to compile from the changed files index. *)
 let should_capture_file_from_index () =