Make decl_names_equal more accurate
Commit Message
This utility function compares qualified names component-wise with
special handling of components that are anonymous names.
The code is incorrect for some cases when there are different numbers
of components on each side. Also, the control flow in the loop body is
more complex than it needs to be.
This commit simplifies the control flow, fixes the comparison bugs and
adds some extra tests to cover these cases.
* src/abg-tools-utils.cc (decl_names_equal): Move {l,r}_pos2
declarations into the loop and make {l,r}_length const. Avoid
chance of arithmetic on string::npos values. Rework
logic so there is a single test for "names compare equal" and
a single test for different numbers of name components.
* tests/test-tools-utils.cc (main): Add nine more tests.
Signed-off-by: Giuliano Procida <gprocida@google.com>
---
src/abg-tools-utils.cc | 72 +++++++++++++++------------------------
tests/test-tools-utils.cc | 10 ++++++
2 files changed, 38 insertions(+), 44 deletions(-)
Comments
Giuliano Procida <gprocida@google.com> a écrit:
> This utility function compares qualified names component-wise with
> special handling of components that are anonymous names.
>
> The code is incorrect for some cases when there are different numbers
> of components on each side. Also, the control flow in the loop body is
> more complex than it needs to be.
I am not sure the result is radically simpler. But I agree it fixes the
problem.
Just for the record, I believe this much shorter change also fixes the
issue:
diff --git a/src/abg-tools-utils.cc b/src/abg-tools-utils.cc
index dfbec87..919b50f 100644
--- a/src/abg-tools-utils.cc
+++ b/src/abg-tools-utils.cc
@@ -540,7 +540,7 @@ decl_names_equal(const string& l, const string& r)
ANONYMOUS_ENUM_INTERNAL_NAME) == 0))
{
if (l_pos2 == l.npos || r_pos2 == r.npos)
- return true;
+ return (l_pos2 == l.npos) == (r_pos2 == r.npos);
l_pos1 = l_pos2 + 2;
r_pos1 = r_pos2 + 2;
But as I don't have any strong opinion either way, I am going with your
patch.
> This commit simplifies the control flow, fixes the comparison bugs and
> adds some extra tests to cover these cases.
>
> * src/abg-tools-utils.cc (decl_names_equal): Move {l,r}_pos2
> declarations into the loop and make {l,r}_length const. Avoid
> chance of arithmetic on string::npos values. Rework
> logic so there is a single test for "names compare equal" and
> a single test for different numbers of name components.
> * tests/test-tools-utils.cc (main): Add nine more tests.
>
> Signed-off-by: Giuliano Procida <gprocida@google.com>
Applied to master, thanks!
Cheers,
@@ -510,61 +510,45 @@ get_anonymous_enum_internal_name_prefix()
bool
decl_names_equal(const string& l, const string& r)
{
- string::size_type l_pos1 = 0, l_pos2 = 0, r_pos1 = 0, r_pos2 = 0;
- string::size_type l_length = l.length(), r_length = r.length();
+ string::size_type l_pos1 = 0, r_pos1 = 0;
+ const string::size_type l_length = l.length(), r_length = r.length();
while (l_pos1 < l_length && r_pos1 < r_length)
{
- l_pos2 = l.find("::", l_pos1);
- r_pos2 = r.find("::", r_pos1);
+ string::size_type l_pos2 = l.find("::", l_pos1);
+ string::size_type r_pos2 = r.find("::", r_pos1);
+ if (l_pos2 == string::npos)
+ l_pos2 = l_length;
+ if (r_pos2 == string::npos)
+ r_pos2 = r_length;
- if ((l.compare(l_pos1,
- ANONYMOUS_STRUCT_INTERNAL_NAME_LEN,
- ANONYMOUS_STRUCT_INTERNAL_NAME) == 0
- && r.compare(r_pos1,
+ if (l.compare(l_pos1, l_pos2 - l_pos1, r,
+ r_pos1, r_pos2 - r_pos1)
+ && (l.compare(l_pos1,
ANONYMOUS_STRUCT_INTERNAL_NAME_LEN,
- ANONYMOUS_STRUCT_INTERNAL_NAME) == 0)
- ||
- (l.compare(l_pos1,
- ANONYMOUS_UNION_INTERNAL_NAME_LEN,
- ANONYMOUS_UNION_INTERNAL_NAME) == 0
- && r.compare(r_pos1,
+ ANONYMOUS_STRUCT_INTERNAL_NAME)
+ || r.compare(r_pos1,
+ ANONYMOUS_STRUCT_INTERNAL_NAME_LEN,
+ ANONYMOUS_STRUCT_INTERNAL_NAME))
+ && (l.compare(l_pos1,
ANONYMOUS_UNION_INTERNAL_NAME_LEN,
- ANONYMOUS_UNION_INTERNAL_NAME) == 0)
- ||
- (l.compare(l_pos1,
- ANONYMOUS_ENUM_INTERNAL_NAME_LEN,
- ANONYMOUS_ENUM_INTERNAL_NAME) == 0
- && r.compare(r_pos1,
+ ANONYMOUS_UNION_INTERNAL_NAME)
+ || r.compare(r_pos1,
+ ANONYMOUS_UNION_INTERNAL_NAME_LEN,
+ ANONYMOUS_UNION_INTERNAL_NAME))
+ && (l.compare(l_pos1,
ANONYMOUS_ENUM_INTERNAL_NAME_LEN,
- ANONYMOUS_ENUM_INTERNAL_NAME) == 0))
- {
- if (l_pos2 == l.npos || r_pos2 == r.npos)
- return true;
-
- l_pos1 = l_pos2 + 2;
- r_pos1 = r_pos2 + 2;
- continue;
- }
-
- if (l_pos2 == l.npos || r_pos2 == r.npos)
- {
- if (l_pos2 != r_pos2)
- return false;
-
- return !l.compare(l_pos1, l_pos2, r,
- r_pos1, r_pos2);
- }
-
- if (l.compare(l_pos1, l_pos2 - l_pos1, r,
- r_pos1, r_pos2 - r_pos1))
+ ANONYMOUS_ENUM_INTERNAL_NAME)
+ || r.compare(r_pos1,
+ ANONYMOUS_ENUM_INTERNAL_NAME_LEN,
+ ANONYMOUS_ENUM_INTERNAL_NAME)))
return false;
- l_pos1 = l_pos2 + 2;
- r_pos1 = r_pos2 + 2;
+ l_pos1 = l_pos2 == l_length ? l_pos2 : l_pos2 + 2;
+ r_pos1 = r_pos2 == r_length ? r_pos2 : r_pos2 + 2;
}
- return true;
+ return (l_pos1 == l_length) == (r_pos1 == r_length);
}
/// If a given file is a symbolic link, get the canonicalized absolute
@@ -86,5 +86,15 @@ main(int, char**)
ABG_ASSERT(decl_names_equal("S0::m2", "S0::m12") == false);
+ ABG_ASSERT(!decl_names_equal("S0::S1", "S0"));
+ ABG_ASSERT(!decl_names_equal("S0", "S0::S1"));
+ ABG_ASSERT(!decl_names_equal("S1::S0", "S0::S1"));
+ ABG_ASSERT(!decl_names_equal("__anonymous_struct__::S0", "__anonymous_struct__"));
+ ABG_ASSERT(!decl_names_equal("__anonymous_struct__", "__anonymous_struct__::S1"));
+ ABG_ASSERT(!decl_names_equal("__anonymous_struct__::S0", "__anonymous_struct__::S1"));
+ ABG_ASSERT(!decl_names_equal("S0::__anonymous_struct__", "__anonymous_struct__"));
+ ABG_ASSERT(!decl_names_equal("__anonymous_struct__", "S1::__anonymous_struct__"));
+ ABG_ASSERT(!decl_names_equal("S0::__anonymous_struct__", "S1::__anonymous_struct__"));
+
return 0;
}