diff mbox series

[03/21] Simplify generation of symbol whitelist regex.

Message ID 20200423154441.170531-4-gprocida@google.com
State Superseded
Headers
Series Simplify regex and suppression parsing. |

Commit Message

Giuliano Procida April 23, 2020, 3:44 p.m. UTC 
  The code to build the symbol whitelist regex uses things like seekp
and tellp to generate regexes like "^foo$|^bar$".

This patch simplifies the code, for further enhancement, resulting in
generated regexes like "^(foo|bar)$".

There should be no change in behaviour, unless whitelisted symbol
names contain special regex characters.

	* include/abg-regex.h (generate_from_strings): Declare new
	function to build a regex from some strings, representing a
	membership test.
	* src/abg-regex.cc (generate_from_strings): Implement new
	function to build a regex from some strings, representing a
	membership test, in a straightfoward fashion.
	* src/abg-tools-utils.cc
	(gen_suppr_spec_from_kernel_abi_whitelists): Replace
	regex-building code with a call to generate_from_strings.
	* tests/test-kmi-whitelist.cc: Update regexes in test.

Signed-off-by: Giuliano Procida <gprocida@google.com>
---
 include/abg-regex.h         |  6 ++++++
 src/abg-regex.cc            | 28 ++++++++++++++++++++++++++++
 src/abg-tools-utils.cc      | 10 +++-------
 tests/test-kmi-whitelist.cc | 10 +++++-----
 4 files changed, 42 insertions(+), 12 deletions(-)
diff mbox series

Patch

diff --git a/include/abg-regex.h b/include/abg-regex.h
index 84c386a9..2f638ef2 100644
--- a/include/abg-regex.h
+++ b/include/abg-regex.h
@@ -27,6 +27,9 @@ 
 
 #include <regex.h>
 
+#include <string>
+#include <vector>
+
 #include "abg-cxx-compat.h"
 #include "abg-sptr-utils.h"
 
@@ -55,6 +58,9 @@  struct regex_t_deleter
   }
 };//end struct regex_deleter
 
+std::string
+generate_from_strings(const std::vector<std::string>& strs);
+
 }// end namespace regex
 
 /// Specialization of sptr_utils::build_sptr for regex_t.
diff --git a/src/abg-regex.cc b/src/abg-regex.cc
index 13f5841d..79a89033 100644
--- a/src/abg-regex.cc
+++ b/src/abg-regex.cc
@@ -23,6 +23,7 @@ 
 /// Some specialization for shared pointer utility templates.
 ///
 
+#include <sstream>
 #include "abg-sptr-utils.h"
 #include "abg-regex.h"
 
@@ -52,4 +53,31 @@  regex::regex_t_sptr
 sptr_utils::build_sptr<regex_t>()
 {return sptr_utils::build_sptr(new regex_t);}
 
+namespace regex
+{
+
+/// Generate a regex pattern equivalent to testing set membership.
+///
+/// A string will match the resulting pattern regex, if and only if it
+/// was present in the vector.
+///
+/// @param strs a vector of strings
+///
+/// @return a regex pattern
+std::string
+generate_from_strings(const std::vector<std::string>& strs)
+{
+  if (strs.empty())
+    return "^_^";
+  std::ostringstream os;
+  std::vector<std::string>::const_iterator i = strs.begin();
+  os << "^(" << *i++;
+  while (i != strs.end())
+    os << "|" << *i++;
+  os << ")$";
+  return os.str();
+}
+
+}//end namespace regex
+
 }//end namespace abigail
diff --git a/src/abg-tools-utils.cc b/src/abg-tools-utils.cc
index a06e8615..11486a21 100644
--- a/src/abg-tools-utils.cc
+++ b/src/abg-tools-utils.cc
@@ -61,6 +61,8 @@ 
 #include "abg-dwarf-reader.h"
 #include "abg-internal.h"
 #include "abg-cxx-compat.h"
+#include "abg-regex.h"
+
 // <headers defining libabigail's API go under here>
 ABG_BEGIN_EXPORT_DECLARATIONS
 
@@ -2002,13 +2004,7 @@  gen_suppr_spec_from_kernel_abi_whitelists
 
       // Build a regular expression representing the union of all
       // the function and variable names expressed in the white list.
-      std::stringstream regex_ss;
-      regex_ss << "^";
-      std::copy(whitelisted_names.begin(), whitelisted_names.end(),
-		std::ostream_iterator<std::string>(regex_ss, "$|^"));
-      regex_ss.seekp(0, std::ios::end);
-      const std::string& regex =
-	  regex_ss.str().substr(0, static_cast<size_t>(regex_ss.tellp()) - 2);
+      const std::string regex = regex::generate_from_strings(whitelisted_names);
 
       // Build a suppression specification which *keeps* functions
       // whose ELF symbols match the regular expression contained
diff --git a/tests/test-kmi-whitelist.cc b/tests/test-kmi-whitelist.cc
index 2aa0f463..bcc5adee 100644
--- a/tests/test-kmi-whitelist.cc
+++ b/tests/test-kmi-whitelist.cc
@@ -96,7 +96,7 @@  TEST_CASE("WhitelistWithASingleEntry", "[whitelists]")
   suppressions_type suppr
       = gen_suppr_spec_from_kernel_abi_whitelists(abi_whitelist_paths);
   REQUIRE(!suppr.empty());
-  test_suppressions_are_consistent(suppr, "^test_symbol$");
+  test_suppressions_are_consistent(suppr, "^(test_symbol)$");
 }
 
 TEST_CASE("WhitelistWithADuplicateEntry", "[whitelists]")
@@ -106,7 +106,7 @@  TEST_CASE("WhitelistWithADuplicateEntry", "[whitelists]")
   suppressions_type suppr
       = gen_suppr_spec_from_kernel_abi_whitelists(abi_whitelist_paths);
   REQUIRE(!suppr.empty());
-  test_suppressions_are_consistent(suppr, "^test_symbol$");
+  test_suppressions_are_consistent(suppr, "^(test_symbol)$");
 }
 
 TEST_CASE("TwoWhitelists", "[whitelists]")
@@ -118,7 +118,7 @@  TEST_CASE("TwoWhitelists", "[whitelists]")
       gen_suppr_spec_from_kernel_abi_whitelists(abi_whitelist_paths);
   REQUIRE(!suppr.empty());
   test_suppressions_are_consistent(suppr,
-				   "^test_another_symbol$|^test_symbol$");
+				   "^(test_another_symbol|test_symbol)$");
 }
 
 TEST_CASE("TwoWhitelistsWithDuplicates", "[whitelists]")
@@ -130,7 +130,7 @@  TEST_CASE("TwoWhitelistsWithDuplicates", "[whitelists]")
       = gen_suppr_spec_from_kernel_abi_whitelists(abi_whitelist_paths);
   REQUIRE(!suppr.empty());
   test_suppressions_are_consistent(suppr,
-				   "^test_another_symbol$|^test_symbol$");
+				   "^(test_another_symbol|test_symbol)$");
 }
 
 TEST_CASE("WhitelistWithTwoSections", "[whitelists]")
@@ -140,5 +140,5 @@  TEST_CASE("WhitelistWithTwoSections", "[whitelists]")
   suppressions_type suppr
       = gen_suppr_spec_from_kernel_abi_whitelists(abi_whitelist_paths);
   REQUIRE(!suppr.empty());
-  test_suppressions_are_consistent(suppr, "^test_symbol1$|^test_symbol2$");
+  test_suppressions_are_consistent(suppr, "^(test_symbol1|test_symbol2)$");
 }