[DB] kill abs_source_file_from_path

Summary:
`abs_source_file_from_path` is dangerous because
1. It's not trying to make path relative to `project_root` - you can't compare two files created with two different methods
2. It's making relative paths relative to `getcwd` instead of `project_root` which is different from `from_string` function.

Also remove unused `DB.inode_equal`

Reviewed By: cristianoc

Differential Revision: D4204891

fbshipit-source-id: c4c2f99

infer/src/base/DB.ml

@@ -56,10 +56,6 @@ let source_file_from_string path =
   else
     Absolute path
 
-(** convert a path to a source file, turning it into an absolute path if necessary *)
-let abs_source_file_from_path fname =
-  Absolute (filename_to_absolute fname)
-
 let rel_path_from_abs_path root fname =
   let relative_complemented_fname = filename_to_relative root fname in
   if string_is_prefix root fname &&
@@ -100,11 +96,6 @@ let source_file_line_count source_file =
   let abs_path = source_file_to_abs_path source_file in
   count_newlines abs_path
 
-let inode_equal sf1 sf2 =
-  let stat1 = Unix.stat (source_file_to_abs_path sf1) in
-  let stat2 = Unix.stat (source_file_to_abs_path sf2) in
-  stat1.st_dev = stat2.st_dev && stat1.st_ino = stat2.st_ino
-
 let source_file_to_rel_path fname =
   match fname with
   | RelativeProjectRoot path -> path

infer/src/base/DB.mli

@@ -95,15 +95,9 @@ val source_file_line_count : source_file -> int
 (** equality of source files *)
 val source_file_equal : source_file -> source_file -> bool
 
-(** equality of the files on disk *)
-val inode_equal : source_file -> source_file -> bool
-
 (** empty source file *)
 val source_file_empty : source_file
 
-(** convert a path to a source file, turning it into an absolute path if necessary *)
-val abs_source_file_from_path : string -> source_file
-
 val source_file_from_abs_path : string -> source_file
 
 (** string encoding of a source file (including path) as a single filename *)