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refactor: move skip methods to abstract parser #2948

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merged 1 commit into from
Mar 19, 2024
Merged

refactor: move skip methods to abstract parser #2948

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166 changes: 166 additions & 0 deletions ...ud-spanner/src/main/java/com/google/cloud/spanner/connection/AbstractStatementParser.java
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Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,7 @@
import java.util.concurrent.Callable;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.annotation.Nullable;

/**
* Internal class for the Spanner Connection API.
Expand Down Expand Up @@ -696,4 +697,169 @@ static int countOccurrencesOf(char c, String string) {
public boolean checkReturningClause(String sql) {
return checkReturningClauseInternal(sql);
}

/**
* Returns true for characters that can be used as the first character in unquoted identifiers.
*/
boolean isValidIdentifierFirstChar(char c) {
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All the methods that are added here, are only copy-pasted from PostgreSQLStatementParser. We do this as step 1 for a larger refactoring, so the next steps are easier to follow and review.

return Character.isLetter(c) || c == UNDERSCORE;
}

/** Returns true for characters that can be used in unquoted identifiers. */
boolean isValidIdentifierChar(char c) {
return isValidIdentifierFirstChar(c) || Character.isDigit(c) || c == DOLLAR;
}

/** Reads a dollar-quoted string literal from position index in the given sql string. */
String parseDollarQuotedString(String sql, int index) {
// Look ahead to the next dollar sign (if any). Everything in between is the quote tag.
StringBuilder tag = new StringBuilder();
while (index < sql.length()) {
char c = sql.charAt(index);
if (c == DOLLAR) {
return tag.toString();
}
if (!isValidIdentifierChar(c)) {
break;
}
tag.append(c);
index++;
}
return null;
}

/**
* Skips the next character, literal, identifier, or comment in the given sql string from the
* given index. The skipped characters are added to result if it is not null.
*/
int skip(String sql, int currentIndex, @Nullable StringBuilder result) {
char currentChar = sql.charAt(currentIndex);
if (currentChar == SINGLE_QUOTE || currentChar == DOUBLE_QUOTE) {
appendIfNotNull(result, currentChar);
return skipQuoted(sql, currentIndex, currentChar, result);
} else if (currentChar == DOLLAR) {
String dollarTag = parseDollarQuotedString(sql, currentIndex + 1);
if (dollarTag != null) {
appendIfNotNull(result, currentChar, dollarTag, currentChar);
return skipQuoted(
sql, currentIndex + dollarTag.length() + 1, currentChar, dollarTag, result);
}
} else if (currentChar == HYPHEN
&& sql.length() > (currentIndex + 1)
&& sql.charAt(currentIndex + 1) == HYPHEN) {
return skipSingleLineComment(sql, currentIndex, result);
} else if (currentChar == SLASH
&& sql.length() > (currentIndex + 1)
&& sql.charAt(currentIndex + 1) == ASTERISK) {
return skipMultiLineComment(sql, currentIndex, result);
}

appendIfNotNull(result, currentChar);
return currentIndex + 1;
}

/** Skips a single-line comment from startIndex and adds it to result if result is not null. */
static int skipSingleLineComment(String sql, int startIndex, @Nullable StringBuilder result) {
int endIndex = sql.indexOf('\n', startIndex + 2);
if (endIndex == -1) {
endIndex = sql.length();
} else {
// Include the newline character.
endIndex++;
}
appendIfNotNull(result, sql.substring(startIndex, endIndex));
return endIndex;
}

/** Skips a multi-line comment from startIndex and adds it to result if result is not null. */
static int skipMultiLineComment(String sql, int startIndex, @Nullable StringBuilder result) {
// Current position is start + '/*'.length().
int pos = startIndex + 2;
// PostgreSQL allows comments to be nested. That is, the following is allowed:
// '/* test /* inner comment */ still a comment */'
int level = 1;
while (pos < sql.length()) {
if (sql.charAt(pos) == SLASH && sql.length() > (pos + 1) && sql.charAt(pos + 1) == ASTERISK) {
level++;
}
if (sql.charAt(pos) == ASTERISK && sql.length() > (pos + 1) && sql.charAt(pos + 1) == SLASH) {
level--;
if (level == 0) {
pos += 2;
appendIfNotNull(result, sql.substring(startIndex, pos));
return pos;
}
}
pos++;
}
appendIfNotNull(result, sql.substring(startIndex));
return sql.length();
}

/** Skips a quoted string from startIndex. */
private int skipQuoted(
String sql, int startIndex, char startQuote, @Nullable StringBuilder result) {
return skipQuoted(sql, startIndex, startQuote, null, result);
}

/**
* Skips a quoted string from startIndex. The quote character is assumed to be $ if dollarTag is
* not null.
*/
private int skipQuoted(
String sql,
int startIndex,
char startQuote,
String dollarTag,
@Nullable StringBuilder result) {
int currentIndex = startIndex + 1;
while (currentIndex < sql.length()) {
char currentChar = sql.charAt(currentIndex);
if (currentChar == startQuote) {
if (currentChar == DOLLAR) {
// Check if this is the end of the current dollar quoted string.
String tag = parseDollarQuotedString(sql, currentIndex + 1);
if (tag != null && tag.equals(dollarTag)) {
appendIfNotNull(result, currentChar, dollarTag, currentChar);
return currentIndex + tag.length() + 2;
}
} else if (sql.length() > currentIndex + 1 && sql.charAt(currentIndex + 1) == startQuote) {
// This is an escaped quote (e.g. 'foo''bar')
appendIfNotNull(result, currentChar);
appendIfNotNull(result, currentChar);
currentIndex += 2;
continue;
} else {
appendIfNotNull(result, currentChar);
return currentIndex + 1;
}
}
currentIndex++;
appendIfNotNull(result, currentChar);
}
throw SpannerExceptionFactory.newSpannerException(
ErrorCode.INVALID_ARGUMENT, "SQL statement contains an unclosed literal: " + sql);
}

/** Appends the given character to result if result is not null. */
private void appendIfNotNull(@Nullable StringBuilder result, char currentChar) {
if (result != null) {
result.append(currentChar);
}
}

/** Appends the given suffix to result if result is not null. */
private static void appendIfNotNull(@Nullable StringBuilder result, String suffix) {
if (result != null) {
result.append(suffix);
}
}

/** Appends the given prefix, tag, and suffix to result if result is not null. */
private static void appendIfNotNull(
@Nullable StringBuilder result, char prefix, String tag, char suffix) {
if (result != null) {
result.append(prefix).append(tag).append(suffix);
}
}
}
147 changes: 0 additions & 147 deletions ...-spanner/src/main/java/com/google/cloud/spanner/connection/PostgreSQLStatementParser.java
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,6 @@
import java.util.HashSet;
import java.util.Set;
import java.util.regex.Pattern;
import javax.annotation.Nullable;

@InternalApi
public class PostgreSQLStatementParser extends AbstractStatementParser {
Expand Down Expand Up @@ -136,23 +135,6 @@ String removeCommentsAndTrimInternal(String sql) {
return res.toString().trim();
}

String parseDollarQuotedString(String sql, int index) {
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This and the other methods here that appear to be deleted, are just moved to AbstractStatementParser, which is the super class of this class. That means that functionally, nothing changes.

// Look ahead to the next dollar sign (if any). Everything in between is the quote tag.
StringBuilder tag = new StringBuilder();
while (index < sql.length()) {
char c = sql.charAt(index);
if (c == DOLLAR) {
return tag.toString();
}
if (!isValidIdentifierChar(c)) {
break;
}
tag.append(c);
index++;
}
return null;
}

/** PostgreSQL does not support statement hints. */
@Override
String removeStatementHint(String sql) {
Expand Down Expand Up @@ -220,135 +202,6 @@ public Set<String> getQueryParameters(String sql) {
return parameters;
}

private int skip(String sql, int currentIndex, @Nullable StringBuilder result) {
char currentChar = sql.charAt(currentIndex);
if (currentChar == SINGLE_QUOTE || currentChar == DOUBLE_QUOTE) {
appendIfNotNull(result, currentChar);
return skipQuoted(sql, currentIndex, currentChar, result);
} else if (currentChar == DOLLAR) {
String dollarTag = parseDollarQuotedString(sql, currentIndex + 1);
if (dollarTag != null) {
appendIfNotNull(result, currentChar, dollarTag, currentChar);
return skipQuoted(
sql, currentIndex + dollarTag.length() + 1, currentChar, dollarTag, result);
}
} else if (currentChar == HYPHEN
&& sql.length() > (currentIndex + 1)
&& sql.charAt(currentIndex + 1) == HYPHEN) {
return skipSingleLineComment(sql, currentIndex, result);
} else if (currentChar == SLASH
&& sql.length() > (currentIndex + 1)
&& sql.charAt(currentIndex + 1) == ASTERISK) {
return skipMultiLineComment(sql, currentIndex, result);
}

appendIfNotNull(result, currentChar);
return currentIndex + 1;
}

static int skipSingleLineComment(String sql, int currentIndex, @Nullable StringBuilder result) {
int endIndex = sql.indexOf('\n', currentIndex + 2);
if (endIndex == -1) {
endIndex = sql.length();
} else {
// Include the newline character.
endIndex++;
}
appendIfNotNull(result, sql.substring(currentIndex, endIndex));
return endIndex;
}

static int skipMultiLineComment(String sql, int startIndex, @Nullable StringBuilder result) {
// Current position is start + '/*'.length().
int pos = startIndex + 2;
// PostgreSQL allows comments to be nested. That is, the following is allowed:
// '/* test /* inner comment */ still a comment */'
int level = 1;
while (pos < sql.length()) {
if (sql.charAt(pos) == SLASH && sql.length() > (pos + 1) && sql.charAt(pos + 1) == ASTERISK) {
level++;
}
if (sql.charAt(pos) == ASTERISK && sql.length() > (pos + 1) && sql.charAt(pos + 1) == SLASH) {
level--;
if (level == 0) {
pos += 2;
appendIfNotNull(result, sql.substring(startIndex, pos));
return pos;
}
}
pos++;
}
appendIfNotNull(result, sql.substring(startIndex));
return sql.length();
}

private int skipQuoted(
String sql, int startIndex, char startQuote, @Nullable StringBuilder result) {
return skipQuoted(sql, startIndex, startQuote, null, result);
}

private int skipQuoted(
String sql,
int startIndex,
char startQuote,
String dollarTag,
@Nullable StringBuilder result) {
int currentIndex = startIndex + 1;
while (currentIndex < sql.length()) {
char currentChar = sql.charAt(currentIndex);
if (currentChar == startQuote) {
if (currentChar == DOLLAR) {
// Check if this is the end of the current dollar quoted string.
String tag = parseDollarQuotedString(sql, currentIndex + 1);
if (tag != null && tag.equals(dollarTag)) {
appendIfNotNull(result, currentChar, dollarTag, currentChar);
return currentIndex + tag.length() + 2;
}
} else if (sql.length() > currentIndex + 1 && sql.charAt(currentIndex + 1) == startQuote) {
// This is an escaped quote (e.g. 'foo''bar')
appendIfNotNull(result, currentChar);
appendIfNotNull(result, currentChar);
currentIndex += 2;
continue;
} else {
appendIfNotNull(result, currentChar);
return currentIndex + 1;
}
}
currentIndex++;
appendIfNotNull(result, currentChar);
}
throw SpannerExceptionFactory.newSpannerException(
ErrorCode.INVALID_ARGUMENT, "SQL statement contains an unclosed literal: " + sql);
}

private void appendIfNotNull(@Nullable StringBuilder result, char currentChar) {
if (result != null) {
result.append(currentChar);
}
}

private static void appendIfNotNull(@Nullable StringBuilder result, String suffix) {
if (result != null) {
result.append(suffix);
}
}

private void appendIfNotNull(
@Nullable StringBuilder result, char prefix, String tag, char suffix) {
if (result != null) {
result.append(prefix).append(tag).append(suffix);
}
}

private boolean isValidIdentifierFirstChar(char c) {
return Character.isLetter(c) || c == UNDERSCORE;
}

private boolean isValidIdentifierChar(char c) {
return isValidIdentifierFirstChar(c) || Character.isDigit(c) || c == DOLLAR;
}

private boolean checkCharPrecedingReturning(char ch) {
return (ch == SPACE)
|| (ch == SINGLE_QUOTE)
Expand Down