atris commented on code in PR #10897:
URL: https://github.com/apache/pinot/pull/10897#discussion_r1228567126
##########
pinot-common/src/main/java/org/apache/pinot/common/utils/RegexpPatternConverterUtils.java:
##########
@@ -18,16 +18,23 @@
*/
package org.apache.pinot.common.utils;
+import com.google.common.collect.ImmutableSet;
+import java.util.Set;
+
/**
* Utility for converting regex patterns.
*/
public class RegexpPatternConverterUtils {
private RegexpPatternConverterUtils() {
}
- /* Represents all metacharacters to be processed */
- public static final String[] REGEXP_METACHARACTERS =
- {"\\", "^", "$", ".", "{", "}", "[", "]", "(", ")", "*", "+", "?", "|",
"<", ">", "-", "&", "/"};
+ /*
+ * Represents all metacharacters to be processed.
+ * This excludes the \ (back slash) character as that doubles up as an
escape character as well.
+ * So it is handled separately in the conversion logic.
+ */
+ public static final Set<String> REGEXP_METACHARACTERS = ImmutableSet.of(
Review Comment:
Why the move to a set? Since the number of characters is small, isn't an
array more space efficient?
##########
pinot-common/src/main/java/org/apache/pinot/common/utils/RegexpPatternConverterUtils.java:
##########
@@ -64,24 +71,42 @@ public static String likeToRegexpLike(String likePattern) {
break;
}
- String escaped = escapeMetaCharacters(likePattern.substring(start, end));
- StringBuilder sb = new StringBuilder(escaped.length() + 2);
+ likePattern = likePattern.substring(start, end);
+ StringBuilder sb = new StringBuilder();
sb.append(prefix);
- sb.append(escaped);
- sb.append(suffix);
+ // handling SQL wildcards by replacing them with corresponding regex
equivalents
+ // we ignore them if the SQL wildcards are escaped
int i = 0;
- while (i < sb.length()) {
- char c = sb.charAt(i);
+ boolean isPrevCharBackSlash = false;
+ while (i < likePattern.length()) {
+ char c = likePattern.charAt(i);
if (c == '_') {
- sb.replace(i, i + 1, ".");
+ sb.append(isPrevCharBackSlash ? c : ".");
} else if (c == '%') {
- sb.replace(i, i + 1, ".*");
- i++;
+ sb.append(isPrevCharBackSlash ? c : ".*");
Review Comment:
Why was this logic moved out of escapeMetaCharacters?
##########
pinot-common/src/main/java/org/apache/pinot/common/utils/RegexpPatternConverterUtils.java:
##########
@@ -64,24 +71,42 @@ public static String likeToRegexpLike(String likePattern) {
break;
}
- String escaped = escapeMetaCharacters(likePattern.substring(start, end));
- StringBuilder sb = new StringBuilder(escaped.length() + 2);
+ likePattern = likePattern.substring(start, end);
+ StringBuilder sb = new StringBuilder();
sb.append(prefix);
- sb.append(escaped);
- sb.append(suffix);
+ // handling SQL wildcards by replacing them with corresponding regex
equivalents
+ // we ignore them if the SQL wildcards are escaped
int i = 0;
- while (i < sb.length()) {
- char c = sb.charAt(i);
+ boolean isPrevCharBackSlash = false;
+ while (i < likePattern.length()) {
+ char c = likePattern.charAt(i);
if (c == '_') {
- sb.replace(i, i + 1, ".");
+ sb.append(isPrevCharBackSlash ? c : ".");
} else if (c == '%') {
- sb.replace(i, i + 1, ".*");
- i++;
+ sb.append(isPrevCharBackSlash ? c : ".*");
+ } else if (REGEXP_METACHARACTERS.contains(String.valueOf(c))) {
+ sb.append('\\').append(c);
+ } else {
+ if (isPrevCharBackSlash) {
+ // this means the previous character is a \
+ // but it was not used for escaping SQL wildcards
+ // so let's escape this \ in the output
+ // this case is separately handled outside of the meta characters
list
+ sb.append('\\');
Review Comment:
Why can this be not merged with line 89?
##########
pinot-common/src/main/java/org/apache/pinot/common/utils/RegexpPatternConverterUtils.java:
##########
@@ -64,24 +71,42 @@ public static String likeToRegexpLike(String likePattern) {
break;
}
- String escaped = escapeMetaCharacters(likePattern.substring(start, end));
- StringBuilder sb = new StringBuilder(escaped.length() + 2);
+ likePattern = likePattern.substring(start, end);
+ StringBuilder sb = new StringBuilder();
sb.append(prefix);
- sb.append(escaped);
- sb.append(suffix);
+ // handling SQL wildcards by replacing them with corresponding regex
equivalents
+ // we ignore them if the SQL wildcards are escaped
int i = 0;
- while (i < sb.length()) {
- char c = sb.charAt(i);
+ boolean isPrevCharBackSlash = false;
+ while (i < likePattern.length()) {
+ char c = likePattern.charAt(i);
if (c == '_') {
- sb.replace(i, i + 1, ".");
Review Comment:
NIT: Lets use constant named variables instead of symbols here
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