[DB] Cleanup code related to --changed-files-index

Summary:
Clean up code related to --changed-files-index option:
1. Store DB.SourceFileSet.t in DB.changed_source_files_set
2. Refactor rest of the code to use it
3. Bunch of minor changes to make code more consise

Reviewed By: jberdine

Differential Revision: D4238736

fbshipit-source-id: 51e5684

infer/src/backend/clusterMakefile.ml

@@ -25,12 +25,7 @@ let source_file_to_pname fname =
 
 let cluster_should_be_analyzed cluster =
   let fname = DB.source_dir_to_string cluster in
-  let in_ondemand_config =
-    match Lazy.force Ondemand.dirs_to_analyze with
-    | None ->
-        None
-    | Some set ->
-        Some (StringSet.mem fname set) in
+  let in_ondemand_config = Option.map (StringSet.mem fname) Ondemand.dirs_to_analyze in
   let check_modified () =
     let modified =
       DB.file_was_updated_after_start (DB.filename_from_string fname) in

infer/src/backend/ondemand.ml

@@ -14,23 +14,16 @@ open! Utils
 module L = Logging
 module F = Format
 
-(** Read the directories to analyze from the ondemand file. *)
-let read_dirs_to_analyze () =
-  match DB.read_changed_files_index with
-  | None ->
-      None
-  | Some lines ->
-      let res = ref StringSet.empty in
-      let do_line line =
-        let rel_file = DB.source_file_to_rel_path (DB.source_file_from_string line) in
-        let source_dir = DB.source_dir_from_source_file (DB.source_file_from_string rel_file) in
-        res := StringSet.add (DB.source_dir_to_string source_dir) !res in
-      IList.iter do_line lines;
-      Some !res
-
 (** Directories to analyze from the ondemand file. *)
 let dirs_to_analyze =
-  lazy (read_dirs_to_analyze ())
+  let process_changed_files changed_files =
+    DB.SourceFileSet.fold
+      (fun source_file source_dir_set ->
+         let source_dir = DB.source_dir_from_source_file source_file in
+         StringSet.add (DB.source_dir_to_string source_dir) source_dir_set
+      )
+      changed_files StringSet.empty in
+  Option.map process_changed_files DB.changed_source_files_set
 
 type analyze_ondemand = DB.source_file -> Procdesc.t -> unit
 

infer/src/backend/ondemand.mli

@@ -12,7 +12,7 @@ open! Utils
 (** Module for on-demand analysis. *)
 
 (** Optional set of source dirs to analyze in on-demand mode. *)
-val dirs_to_analyze : StringSet.t option Lazy.t
+val dirs_to_analyze : StringSet.t option
 
 type analyze_ondemand = DB.source_file -> Procdesc.t -> unit
 

infer/src/base/DB.ml

@@ -419,8 +419,10 @@ let fold_paths_matching ~dir ~p ~init ~f =
 let paths_matching dir p =
   fold_paths_matching ~dir ~p ~init:[] ~f:(fun x xs -> x :: xs)
 
-let read_changed_files_index =
-  match Config.changed_files_index with
-  | None -> None
-  | Some fname ->
-      read_file (source_file_to_abs_path (source_file_from_string fname))
+let changed_source_files_set =
+  Option.map_default read_file None Config.changed_files_index |>
+  Option.map (
+    IList.fold_left
+      (fun changed_files line -> SourceFileSet.add (source_file_from_string line) changed_files)
+      SourceFileSet.empty
+  )

infer/src/base/DB.mli

@@ -174,4 +174,5 @@ val fold_paths_matching :
 (** Return all file paths recursively under the given directory which match the given predicate *)
 val paths_matching : string -> (string -> bool) -> string list
 
-val read_changed_files_index : string list option
+(** Set of files read from --changed-files-index file, None if option not specified *)
+val changed_source_files_set :  SourceFileSet.t option

infer/src/integration/CaptureCompilationDatabase.ml

@@ -16,24 +16,22 @@ let capture_text =
   if Config.analyzer = Config.Linters then "linting"
   else "translating"
 
-let replace_header_file_with_source_file file_path =
-  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 () =
-  match DB.read_changed_files_index with
+  match DB.changed_source_files_set with
   | None ->
       (match Config.changed_files_index with
        | Some index ->
            Process.print_error_and_exit "Error reading the changed files index %s.\n%!" index
        | None -> function _ -> true)
-  | Some lines ->
-      let index_files_set = IList.fold_left
-          (fun changed_files line ->
-             let file = replace_header_file_with_source_file (DB.source_file_from_string line) in
-             DB.SourceFileSet.add file changed_files)
-          DB.SourceFileSet.empty lines in
-      function source_file -> DB.SourceFileSet.mem source_file index_files_set
+  | Some files_set ->
+      function source_file ->
+        DB.SourceFileSet.mem source_file files_set ||
+        (* as fallback try to capture corresponding source file for headers *)
+        Option.map_default
+          (fun src -> DB.SourceFileSet.mem src files_set)
+          false
+          (DB.source_file_of_header source_file)
 
 (** The buck targets are assumed to start with //, aliases are not supported. *)
 let check_args_for_targets args =