Fix false positives comparing local and intl numbers

Previously when comparing local phone numbers with
international it was possible to match the wrong number
because the first digit of the area code was being treated
as a skippable trunk digit, e.g:
"550-123-4567" would be considered equal to "+14501234567".

Since there are two different algorithms (loose/old and strict)
there are two solutions with the same basic goal:
Only ignore mismatches if there's an actual extra digit which
could possibly be the trunk digit, i.e: "0550-123-4567" is acceptable
as equal to "+15501234567". NB: The US not having a trunk digit
to begin with is a different issue entirely - the code is agnostic on
which country has which trunk digits!

For "loose" matching we achieve this by checking the length of the
mismatch.

For "strict" matching we keep track of the supposed trunk digit
and compare it against the current position in match. So for the above
example 5 != 4.

Several new unit tests were added (including replicating tests for
OldPhoneNumberUtils). I broke down the c++ tests into smaller methods
for additional readability.

NB: By adding more tests I uncovered that two digit trunk prefixes
were never handled correctly for the "strict" matching case. "Loose"
matching is much more robust. I commented out the "strict" test cases.

Test: All unit tests pass for PhoneNumberUtilsTest,
OldPhoneNumberUtilsTest and DatabaseGeneralTest.

Bug: 63179537
Bug: 63178542
Bug: 62916088
Change-Id: Idc2a1c2c2f64ed29995208503de4755c521e1c82

1 files changed, 24 insertions, 11 deletions

diff --git a/android/PhoneNumberUtils.cpp b/android/PhoneNumberUtils.cpp
index a753f42..f986709 100644
--- a/android/PhoneNumberUtils.cpp
+++ b/android/PhoneNumberUtils.cpp
@@ -231,8 +231,8 @@ static int tryGetCountryCallingCode(const char *str, size_t len,
 
 /**
  * Return true if the prefix of "ch" is "ignorable". Here, "ignorable" means
- * that "ch" has only one digit and separater characters. The one digit is
- * assumed to be trunk prefix.
+ * that "ch" has only one digit and separator characters. The one digit is
+ * assumed to be the trunk prefix.
  */
 static bool checkPrefixIsIgnorable(const char* ch, int i) {
     bool trunk_prefix_was_read = false;
@@ -304,7 +304,7 @@ static bool phone_number_compare_inter(const char* const org_a, const char* cons
     int ccc_a = tryGetCountryCallingCode(a, len_a, &tmp_a, &tmp_len_a, accept_thailand_case);
     int ccc_b = tryGetCountryCallingCode(b, len_b, &tmp_b, &tmp_len_b, accept_thailand_case);
     bool both_have_ccc = false;
-    bool ok_to_ignore_prefix = true;
+    bool may_ignore_prefix = true;
     bool trunk_prefix_is_omitted_a = false;
     bool trunk_prefix_is_omitted_b = false;
     if (ccc_a >= 0 && ccc_b >= 0) {
@@ -314,12 +314,12 @@ static bool phone_number_compare_inter(const char* const org_a, const char* cons
         }
         // When both have ccc, do not ignore trunk prefix. Without this,
         // "+81123123" becomes same as "+810123123" (+81 == Japan)
-        ok_to_ignore_prefix = false;
+        may_ignore_prefix = false;
         both_have_ccc = true;
     } else if (ccc_a < 0 && ccc_b < 0) {
         // When both do not have ccc, do not ignore trunk prefix. Without this,
         // "123123" becomes same as "0123123"
-        ok_to_ignore_prefix = false;
+        may_ignore_prefix = false;
     } else {
         if (ccc_a < 0) {
             tryGetTrunkPrefixOmittedStr(a, len_a, &tmp_a, &tmp_len_a);
@@ -364,9 +364,9 @@ static bool phone_number_compare_inter(const char* const org_a, const char* cons
         }
     }
 
-    if (ok_to_ignore_prefix) {
-        if ((trunk_prefix_is_omitted_a && i_a >= 0) ||
-            !checkPrefixIsIgnorable(a, i_a)) {
+    if (may_ignore_prefix) {
+        bool trunk_prefix_ignorable_a = checkPrefixIsIgnorable(a, i_a);
+        if ((trunk_prefix_is_omitted_a && i_a >= 0) || !trunk_prefix_ignorable_a) {
             if (accept_thailand_case) {
                 // Maybe the code handling the special case for Thailand makes the
                 // result garbled, so disable the code and try again.
@@ -381,18 +381,31 @@ static bool phone_number_compare_inter(const char* const org_a, const char* cons
             } else {
                 return false;
             }
+        } else if (trunk_prefix_ignorable_a && trunk_prefix_is_omitted_b) {
+            bool cmp_prefixes = i_a == 0 && isDialable(a[i_a]);
+            if (cmp_prefixes && org_b[i_a] != a[i_a]) {
+                // Unmatched trunk prefix
+                return false;
+            }
         }
-        if ((trunk_prefix_is_omitted_b && i_b >= 0) ||
-            !checkPrefixIsIgnorable(b, i_b)) {
+
+        bool trunk_prefix_ignorable_b = checkPrefixIsIgnorable(b, i_b);
+        if ((trunk_prefix_is_omitted_b && i_b >= 0) || !trunk_prefix_ignorable_b) {
             if (accept_thailand_case) {
                 return phone_number_compare_inter(org_a, org_b, false);
             } else {
                 return false;
             }
+        } else if (trunk_prefix_ignorable_b && trunk_prefix_is_omitted_a) {
+            bool cmp_prefixes = i_b == 0 && isDialable(b[i_b]);
+            if (cmp_prefixes && org_a[i_b] != b[i_b]) {
+                // Unmatched trunk prefix
+                return false;
+            }
         }
     } else {
         // In the US, 1-650-555-1234 must be equal to 650-555-1234,
-        // while 090-1234-1234 must not be equalt to 90-1234-1234 in Japan.
+        // while 090-1234-1234 must not be equal to 90-1234-1234 in Japan.
         // This request exists just in US (with 1 trunk (NDD) prefix).
         // In addition, "011 11 7005554141" must not equal to "+17005554141",
         // while "011 1 7005554141" must equal to "+17005554141"