From 8b7c559f6c619bab8a708358db15b2959623c833 Mon Sep 17 00:00:00 2001

From: Pino Toscano <ptoscano@redhat.com>

Date: Tue, 19 Feb 2019 14:54:31 +0100

Subject: [PATCH] v2v: add Var_expander

This helper module provides a facility to replace %{FOO}-like variables

in text strings with user-provided content.

(cherry picked from commit a27748d7000f417c16045967497208d275a09ce8)

---

 .gitignore                |   1 +

 v2v/Makefile.am           |  32 ++++++++++-

 v2v/dummy.c               |   2 +

 v2v/var_expander.ml       |  72 ++++++++++++++++++++++++

 v2v/var_expander.mli      |  82 +++++++++++++++++++++++++++

 v2v/var_expander_tests.ml | 113 ++++++++++++++++++++++++++++++++++++++

 6 files changed, 300 insertions(+), 2 deletions(-)

 create mode 100644 v2v/dummy.c

 create mode 100644 v2v/var_expander.ml

 create mode 100644 v2v/var_expander.mli

 create mode 100644 v2v/var_expander_tests.ml

diff --git a/.gitignore b/.gitignore

index 637bf7765..f2efcdde2 100644

--- a/.gitignore

+++ b/.gitignore

@@ -693,6 +693,7 @@ Makefile.in

 /v2v/uefi.ml

 /v2v/uefi.mli

 /v2v/v2v_unit_tests

+/v2v/var_expander_tests

 /v2v/virt-v2v

 /v2v/virt-v2v.1

 /v2v/virt-v2v-copy-to-local

diff --git a/v2v/Makefile.am b/v2v/Makefile.am

index 2312812fb..f196be81d 100644

--- a/v2v/Makefile.am

+++ b/v2v/Makefile.am

@@ -98,6 +98,7 @@ SOURCES_MLI = \

 	utils.mli \

 	v2v.mli \

 	vCenter.mli \

+	var_expander.mli \

 	windows.mli \

 	windows_virtio.mli

@@ -106,6 +107,7 @@ SOURCES_ML = \

 	types.ml \

 	uefi.ml \

 	utils.ml \

+	var_expander.ml \

 	python_script.ml \

 	name_from_disk.ml \

 	vCenter.ml \

@@ -442,7 +444,7 @@ TESTS += \

 endif

 if HAVE_OCAML_PKG_OUNIT

-TESTS += v2v_unit_tests

+TESTS += v2v_unit_tests var_expander_tests

 endif

 if ENABLE_APPLIANCE

@@ -651,7 +653,7 @@ EXTRA_DIST += \

 # Unit tests.

 check_PROGRAMS =

 if HAVE_OCAML_PKG_OUNIT

-check_PROGRAMS += v2v_unit_tests

+check_PROGRAMS += v2v_unit_tests var_expander_tests

 endif

 v2v_unit_tests_BOBJECTS = \

@@ -671,13 +673,28 @@ v2v_unit_tests_SOURCES = $(virt_v2v_SOURCES)

 v2v_unit_tests_CPPFLAGS = $(virt_v2v_CPPFLAGS)

 v2v_unit_tests_CFLAGS = $(virt_v2v_CFLAGS)

+var_expander_tests_BOBJECTS = \

+	var_expander.cmo \

+	var_expander_tests.cmo

+var_expander_tests_XOBJECTS = $(var_expander_tests_BOBJECTS:.cmo=.cmx)

+

+var_expander_tests_SOURCES = dummy.c

+var_expander_tests_CPPFLAGS = $(virt_v2v_CPPFLAGS)

+var_expander_tests_CFLAGS = $(virt_v2v_CFLAGS)

+

 if !HAVE_OCAMLOPT

 # Can't call this v2v_unit_tests_OBJECTS because automake gets confused.

 v2v_unit_tests_THEOBJECTS = $(v2v_unit_tests_BOBJECTS)

 v2v_unit_tests.cmo: OCAMLPACKAGES += -package oUnit

+

+var_expander_tests_THEOBJECTS = $(var_expander_tests_BOBJECTS)

+var_expander_tests.cmo: OCAMLPACKAGES += -package oUnit

 else

 v2v_unit_tests_THEOBJECTS = $(v2v_unit_tests_XOBJECTS)

 v2v_unit_tests.cmx: OCAMLPACKAGES += -package oUnit

+

+var_expander_tests_THEOBJECTS = $(var_expander_tests_XOBJECTS)

+var_expander_tests.cmx: OCAMLPACKAGES += -package oUnit

 endif

 v2v_unit_tests_DEPENDENCIES = \

@@ -696,6 +713,17 @@ v2v_unit_tests_LINK = \

 	  $(OCAMLLINKFLAGS) \

 	  $(v2v_unit_tests_THEOBJECTS) -o $@

+var_expander_tests_DEPENDENCIES = \

+	$(var_expander_tests_THEOBJECTS) \

+	../common/mlpcre/mlpcre.$(MLARCHIVE) \

+	$(top_srcdir)/ocaml-link.sh

+var_expander_tests_LINK = \

+	$(top_srcdir)/ocaml-link.sh -cclib '$(OCAMLCLIBS)' -- \

+	  $(OCAMLFIND) $(BEST) $(OCAMLFLAGS) \

+	  $(OCAMLPACKAGES) -package oUnit \

+	  $(OCAMLLINKFLAGS) \

+	  $(var_expander_tests_THEOBJECTS) -o $@

+

 # Dependencies.

 .depend: \

 	$(srcdir)/*.mli \

diff --git a/v2v/dummy.c b/v2v/dummy.c

new file mode 100644

index 000000000..ebab6198c

--- /dev/null

+++ b/v2v/dummy.c

@@ -0,0 +1,2 @@

+/* Dummy source, to be used for OCaml-based tools with no C sources. */

+enum { foo = 1 };

diff --git a/v2v/var_expander.ml b/v2v/var_expander.ml

new file mode 100644

index 000000000..24b9bafe3

--- /dev/null

+++ b/v2v/var_expander.ml

@@ -0,0 +1,72 @@

+(* virt-v2v

+ * Copyright (C) 2019 Red Hat Inc.

+ *

+ * This program is free software; you can redistribute it and/or modify

+ * it under the terms of the GNU General Public License as published by

+ * the Free Software Foundation; either version 2 of the License, or

+ * (at your option) any later version.

+ *

+ * This program is distributed in the hope that it will be useful,

+ * but WITHOUT ANY WARRANTY; without even the implied warranty of

+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+ * GNU General Public License for more details.

+ *

+ * You should have received a copy of the GNU General Public License along

+ * with this program; if not, write to the Free Software Foundation, Inc.,

+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

+ *)

+

+open Std_utils

+

+exception Invalid_variable of string

+

+let var_re = PCRE.compile "(^|[^%])%{([^}]+)}"

+

+let check_variable var =

+  String.iter (

+    function

+    | '0'..'9'

+    | 'a'..'z'

+    | 'A'..'Z'

+    | '_'

+    | '-' -> ()

+    | _ -> raise (Invalid_variable var)

+  ) var

+

+let scan_variables str =

+  let res = ref [] in

+  let offset = ref 0 in

+  while PCRE.matches ~offset:!offset var_re str; do

+    let var = PCRE.sub 2 in

+    check_variable var;

+    let _, end_ = PCRE.subi 0 in

+    List.push_back res var;

+    offset := end_

+  done;

+  List.remove_duplicates !res

+

+let replace_fn str fn =

+  let res = ref str in

+  let offset = ref 0 in

+  while PCRE.matches ~offset:!offset var_re !res; do

+    let var = PCRE.sub 2 in

+    check_variable var;

+    let start_, end_ = PCRE.subi 0 in

+    match fn var with

+    | None ->

+      offset := end_

+    | Some text ->

+      let prefix_len =

+        let prefix_start, prefix_end = PCRE.subi 1 in

+        prefix_end - prefix_start in

+      res := (String.sub !res 0 (start_ + prefix_len)) ^ text ^ (String.sub !res end_ (String.length !res - end_));

+      offset := start_ + prefix_len + String.length text

+  done;

+  !res

+

+let replace_list str lst =

+  let fn var =

+    try Some (List.assoc var lst)

+    with Not_found -> None

+  in

+  replace_fn str fn

diff --git a/v2v/var_expander.mli b/v2v/var_expander.mli

new file mode 100644

index 000000000..80aa33c2c

--- /dev/null

+++ b/v2v/var_expander.mli

@@ -0,0 +1,82 @@

+(* virt-v2v

+ * Copyright (C) 2019 Red Hat Inc.

+ *

+ * This program is free software; you can redistribute it and/or modify

+ * it under the terms of the GNU General Public License as published by

+ * the Free Software Foundation; either version 2 of the License, or

+ * (at your option) any later version.

+ *

+ * This program is distributed in the hope that it will be useful,

+ * but WITHOUT ANY WARRANTY; without even the implied warranty of

+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+ * GNU General Public License for more details.

+ *

+ * You should have received a copy of the GNU General Public License along

+ * with this program; if not, write to the Free Software Foundation, Inc.,

+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

+ *)

+

+(** Simple variable expander.

+

+    This module provides the support to expand variables in strings,

+    specified in the form of [%{name}].

+

+    For example:

+

+{v

+let str = "variable-%{INDEX} in %{INDEX} replaced %{INDEX} times"

+let index = ref 0

+let fn = function

+  | "INDEX" ->

+    incr index;

+    Some (string_of_int !index)

+  | _ -> None

+in

+let str = Var_expander.replace_fn str fn

+(* now str is "variable-1 in 2 replaced 3 times" *)

+v}

+

+    The names of variables can contain only ASCII letters (uppercase,

+    and lowercase), digits, underscores, and dashes.

+

+    The replacement is done in a single pass: this means that if a

+    variable is replaced with the text of a variable, that new text

+    is kept as is in the final output.  In practice:

+

+{v

+let str = "%{VAR}"

+let str = Var_expander.replace_list str [("VAR", "%{VAR}")]

+(* now str is "%{VAR}" *)

+v}

+*)

+

+exception Invalid_variable of string

+(** Invalid variable name error.

+

+    In case a variable contains characters not allowed, then this

+    exception with the actual unacceptable variable. *)

+

+val scan_variables : string -> string list

+(** Scan the pattern string for all the variables available.

+

+    This can raise {!Invalid_variable} in case there are invalid

+    variable names. *)

+

+val replace_fn : string -> (string -> string option) -> string

+(** Replaces a string expanding all the variables.

+

+    The replacement function specify how a variable is replaced;

+    if [None] is returned, then that variable is not replaced.

+

+    This can raise {!Invalid_variable} in case there are invalid

+    variable names. *)

+

+val replace_list : string -> (string * string) list -> string

+(** Replaces a string expanding all the variables.

+

+    The replacement list specify how a variable is replaced;

+    if it is not specified in the list, then that variable is not

+    replaced.

+

+    This can raise {!Invalid_variable} in case there are invalid

+    variable names. *)

diff --git a/v2v/var_expander_tests.ml b/v2v/var_expander_tests.ml

new file mode 100644

index 000000000..35b628369

--- /dev/null

+++ b/v2v/var_expander_tests.ml

@@ -0,0 +1,113 @@

+(* virt-v2v

+ * Copyright (C) 2019 Red Hat Inc.

+ *

+ * This program is free software; you can redistribute it and/or modify

+ * it under the terms of the GNU General Public License as published by

+ * the Free Software Foundation; either version 2 of the License, or

+ * (at your option) any later version.

+ *

+ * This program is distributed in the hope that it will be useful,

+ * but WITHOUT ANY WARRANTY; without even the implied warranty of

+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+ * GNU General Public License for more details.

+ *

+ * You should have received a copy of the GNU General Public License along

+ * with this program; if not, write to the Free Software Foundation, Inc.,

+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

+ *)

+

+open Printf

+open OUnit

+

+open Std_utils

+

+let assert_equal_string = assert_equal ~printer:identity

+let assert_equal_stringlist = assert_equal ~printer:(fun x -> "(" ^ (String.escaped (String.concat "," x)) ^ ")")

+

+let replace_none_fn _ = None

+let replace_empty_fn _ = Some ""

+

+let test_no_replacement () =

+  assert_equal_string "" (Var_expander.replace_fn "" replace_none_fn);

+  assert_equal_string "x" (Var_expander.replace_fn "x" replace_none_fn);

+  assert_equal_string "%{}" (Var_expander.replace_fn "%{}" replace_none_fn);

+  assert_equal_string "%{EMPTY}" (Var_expander.replace_fn "%{EMPTY}" replace_none_fn);

+  assert_equal_string "%{EMPTY} %{no}" (Var_expander.replace_fn "%{EMPTY} %{no}" replace_none_fn);

+  assert_equal_string "a %{EMPTY} b" (Var_expander.replace_fn "a %{EMPTY} b" replace_none_fn);

+  ()

+

+let test_replacements () =

+  assert_equal_string "" (Var_expander.replace_fn "%{EMPTY}" replace_empty_fn);

+  assert_equal_string "x " (Var_expander.replace_fn "x %{EMPTY}" replace_empty_fn);

+  assert_equal_string "xy" (Var_expander.replace_fn "x%{EMPTY}y" replace_empty_fn);

+  assert_equal_string "x<->y" (Var_expander.replace_fn "x%{FOO}y" (function | "FOO" -> Some "<->" | _ -> None));

+  assert_equal_string "a x b" (Var_expander.replace_fn "a %{FOO} b" (function | "FOO" -> Some "x" | _ -> None));

+  assert_equal_string "%{FOO} x" (Var_expander.replace_fn "%{FOO} %{BAR}" (function | "BAR" -> Some "x" | _ -> None));

+  assert_equal_string "%{FOO}" (Var_expander.replace_fn "%{BAR}" (function | "BAR" -> Some "%{FOO}" | _ -> None));

+  assert_equal_string "%{FOO} x" (Var_expander.replace_fn "%{BAR} %{FOO}" (function | "BAR" -> Some "%{FOO}" | "FOO" -> Some "x" | _ -> None));

+  begin

+    let str = "%{INDEX}, %{INDEX}, %{INDEX}" in

+    let index = ref 0 in

+    let fn = function

+      | "INDEX" ->

+        incr index;

+        Some (string_of_int !index)

+      | _ -> None

+    in

+    assert_equal_string "1, 2, 3" (Var_expander.replace_fn str fn)

+  end;

+  ()

+

+let test_escape () =

+  assert_equal_string "%%{FOO}" (Var_expander.replace_fn "%%{FOO}" replace_empty_fn);

+  assert_equal_string "x %%{FOO} x" (Var_expander.replace_fn "%{FOO} %%{FOO} %{FOO}" (function | "FOO" -> Some "x" | _ -> None));

+  ()

+

+let test_list () =

+  assert_equal_string "x %{NONE}" (Var_expander.replace_list "%{FOO} %{NONE}" [("FOO", "x")]);

+  ()

+

+let test_scan_variables () =

+  let assert_invalid_variable var =

+    let str = "%{" ^ var ^ "}" in

+    assert_raises (Var_expander.Invalid_variable var)

+                  (fun () -> Var_expander.scan_variables str)

+  in

+  assert_equal_stringlist [] (Var_expander.scan_variables "");

+  assert_equal_stringlist [] (Var_expander.scan_variables "foo");

+  assert_equal_stringlist ["FOO"] (Var_expander.scan_variables "%{FOO}");

+  assert_equal_stringlist ["FOO"; "BAR"] (Var_expander.scan_variables "%{FOO} %{BAR}");

+  assert_equal_stringlist ["FOO"; "BAR"] (Var_expander.scan_variables "%{FOO} %{BAR} %{FOO}");

+  assert_equal_stringlist ["FOO"; "BAR"] (Var_expander.scan_variables "%{FOO} %%{ESCAPED} %{BAR}");

+  assert_invalid_variable "FOO/BAR";

+  ()

+

+let test_errors () =

+  let assert_invalid_variable var =

+    let str = "%{" ^ var ^ "}" in

+    assert_raises (Var_expander.Invalid_variable var)

+                  (fun () -> Var_expander.replace_fn str replace_none_fn)

+  in

+  assert_invalid_variable "FOO/BAR";

+  assert_invalid_variable "FOO:BAR";

+  assert_invalid_variable "FOO(BAR";

+  assert_invalid_variable "FOO)BAR";

+  assert_invalid_variable "FOO@BAR";

+  ()

+

+(* Suites declaration. *)

+let suite =

+  TestList ([

+    "basic" >::: [

+      "no_replacement" >:: test_no_replacement;

+      "replacements" >:: test_replacements;

+      "escape" >:: test_escape;

+      "list" >:: test_list;

+      "scan_variables" >:: test_scan_variables;

+      "errors" >:: test_errors;

+    ];

+  ])

+

+let () =

+  ignore (run_test_tt_main suite);

+  Printf.fprintf stderr "\n"

-- 

2.18.4