lnav/src/sql_util.cc

/**
 * Copyright (c) 2013, Timothy Stack
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * * Neither the name of Timothy Stack nor the names of its contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @file sql_util.cc
 */

#include "config.h"

#include <ctype.h>
#include <stdio.h>
#include <string.h>
#include <pcrecpp.h>

#include <vector>

#include "auto_mem.hh"
#include "sql_util.hh"
#include "lnav_log.hh"
#include "lnav_util.hh"
#include "pcrepp.hh"

using namespace std;

/**
 * Copied from -- http://www.sqlite.org/lang_keywords.html
 */
const char *sql_keywords[] = {
    "ABORT",
    "ACTION",
    "ADD",
    "AFTER",
    "ALL",
    "ALTER",
    "ANALYZE",
    "AND",
    "AS",
    "ASC",
    "ATTACH",
    "AUTOINCREMENT",
    "BEFORE",
    "BEGIN",
    "BETWEEN",
    "BY",
    "CASCADE",
    "CASE",
    "CAST",
    "CHECK",
    "COLLATE",
    "COLUMN",
    "COMMIT",
    "CONFLICT",
    "CONSTRAINT",
    "CREATE",
    "CROSS",
    "CURRENT_DATE",
    "CURRENT_TIME",
    "CURRENT_TIMESTAMP",
    "DATABASE",
    "DEFAULT",
    "DEFERRABLE",
    "DEFERRED",
    "DELETE",
    "DESC",
    "DETACH",
    "DISTINCT",
    "DROP",
    "EACH",
    "ELSE",
    "END",
    "ESCAPE",
    "EXCEPT",
    "EXCLUSIVE",
    "EXISTS",
    "EXPLAIN",
    "FAIL",
    "FOR",
    "FOREIGN",
    "FROM",
    "FULL",
    "GLOB",
    "GROUP BY",
    "HAVING",
    "IF",
    "IGNORE",
    "IMMEDIATE",
    "IN",
    "INDEX",
    "INDEXED",
    "INITIALLY",
    "INNER",
    "INSERT",
    "INSTEAD",
    "INTERSECT",
    "INTO",
    "IS",
    "ISNULL",
    "JOIN",
    "KEY",
    "LEFT",
    "LIKE",
    "LIMIT",
    "MATCH",
    "NATURAL",
    "NO",
    "NOT",
    "NOTNULL",
    "NULL",
    "OF",
    "OFFSET",
    "ON",
    "OR",
    "ORDER BY",
    "OUTER",
    "PLAN",
    "PRAGMA",
    "PRIMARY",
    "QUERY",
    "RAISE",
    "REFERENCES",
    "REGEXP",
    "REINDEX",
    "RELEASE",
    "RENAME",
    "REPLACE",
    "RESTRICT",
    "RIGHT",
    "ROLLBACK",
    "ROW",
    "SAVEPOINT",
    "SELECT",
    "SET",
    "TABLE",
    "TEMP",
    "TEMPORARY",
    "THEN",
    "TO",
    "TRANSACTION",
    "TRIGGER",
    "UNION",
    "UNIQUE",
    "UPDATE",
    "USING",
    "VACUUM",
    "VALUES",
    "VIEW",
    "VIRTUAL",
    "WHEN",
    "WHERE",
    "WITH",

    NULL
};

const char *sql_function_names[] = {
    /* http://www.sqlite.org/lang_aggfunc.html */
    "avg(",
    "count(",
    "group_concat(",
    "max(",
    "min(",
    "sum(",
    "total(",

    /* http://www.sqlite.org/lang_corefunc.html */
    "abs(",
    "changes()",
    "char(",
    "coalesce(",
    "glob(",
    "ifnull(",
    "instr(",
    "hex(",
    "last_insert_rowid()",
    "length(",
    "like(",
    "load_extension(",
    "lower(",
    "ltrim(",
    "nullif(",
    "printf(",
    "quote(",
    "random()",
    "randomblob(",
    "replace(",
    "round(",
    "rtrim(",
    "soundex(",
    "sqlite_compileoption_get(",
    "sqlite_compileoption_used(",
    "sqlite_source_id()",
    "sqlite_version()",
    "substr(",
    "total_changes()",
    "trim(",
    "typeof(",
    "unicode(",
    "upper(",
    "zeroblob(",

    /* http://www.sqlite.org/lang_datefunc.html */
    "date(",
    "time(",
    "datetime(",
    "julianday(",
    "strftime(",

    NULL
};

static int handle_db_list(void *ptr,
                          int ncols,
                          char **colvalues,
                          char **colnames)
{
    struct sqlite_metadata_callbacks *smc;

    smc = (struct sqlite_metadata_callbacks *)ptr;

    smc->smc_db_list[colvalues[1]] = std::vector<std::string>();

    return smc->smc_database_list(ptr, ncols, colvalues, colnames);
}

struct table_list_data {
    struct sqlite_metadata_callbacks *tld_callbacks;
    db_table_map_t::iterator *        tld_iter;
};

static int handle_table_list(void *ptr,
                             int ncols,
                             char **colvalues,
                             char **colnames)
{
    struct table_list_data *tld = (struct table_list_data *)ptr;

    (*tld->tld_iter)->second.push_back(colvalues[0]);

    return tld->tld_callbacks->smc_table_list(tld->tld_callbacks,
                                              ncols,
                                              colvalues,
                                              colnames);
}

int walk_sqlite_metadata(sqlite3 *db, struct sqlite_metadata_callbacks &smc)
{
    auto_mem<char, sqlite3_free> errmsg;
    int retval;

    retval = sqlite3_exec(db,
                          "pragma collation_list",
                          smc.smc_collation_list,
                          &smc,
                          errmsg.out());
    if (retval != SQLITE_OK) {
        log_error("could not get collation list -- %s", errmsg.in());
        return retval;
    }

    retval = sqlite3_exec(db,
                          "pragma database_list",
                          handle_db_list,
                          &smc,
                          errmsg.out());
    if (retval != SQLITE_OK) {
        log_error("could not get DB list -- %s", errmsg.in());
        return retval;
    }

    for (db_table_map_t::iterator iter = smc.smc_db_list.begin();
         iter != smc.smc_db_list.end();
         ++iter) {
        struct table_list_data       tld = { &smc, &iter };
        auto_mem<char, sqlite3_free> query;

        query = sqlite3_mprintf("SELECT name,sql FROM %Q.sqlite_master "
                                "WHERE type in ('table', 'view')",
                                iter->first.c_str());

        retval = sqlite3_exec(db,
                              query,
                              handle_table_list,
                              &tld,
                              errmsg.out());
        if (retval != SQLITE_OK) {
            log_error("could not get table list -- %s", errmsg.in());
            return retval;
        }

        for (db_table_list_t::iterator table_iter = iter->second.begin();
             table_iter != iter->second.end();
             ++table_iter) {
            auto_mem<char, sqlite3_free> table_query;
            std::string &table_name = *table_iter;

            table_query = sqlite3_mprintf(
                "pragma %Q.table_info(%Q)",
                iter->first.c_str(),
                table_name.c_str());
            if (table_query == NULL) {
                return SQLITE_NOMEM;
            }

            retval = sqlite3_exec(db,
                                  table_query,
                                  smc.smc_table_info,
                                  &smc,
                                  errmsg.out());
            if (retval != SQLITE_OK) {
                log_error("could not get table info -- %s", errmsg.in());
                return retval;
            }

            table_query = sqlite3_mprintf(
                "pragma %Q.foreign_key_list(%Q)",
                iter->first.c_str(),
                table_name.c_str());
            if (table_query == NULL) {
                return SQLITE_NOMEM;
            }

            retval = sqlite3_exec(db,
                                  table_query,
                                  smc.smc_foreign_key_list,
                                  &smc,
                                  errmsg.out());
            if (retval != SQLITE_OK) {
                log_error("could not get foreign key list -- %s", errmsg.in());
                return retval;
            }
        }
    }

    return retval;
}

static int schema_collation_list(void *ptr,
                                 int ncols,
                                 char **colvalues,
                                 char **colnames)
{
    return 0;
}

static int schema_db_list(void *ptr,
                          int ncols,
                          char **colvalues,
                          char **colnames)
{
    struct sqlite_metadata_callbacks *smc = (sqlite_metadata_callbacks *)ptr;
    string &schema_out = *((string *)smc->smc_userdata);
    auto_mem<char, sqlite3_free> attach_sql;

    attach_sql = sqlite3_mprintf("ATTACH DATABASE %Q AS %Q;\n",
        colvalues[2], colvalues[1]);

    schema_out += attach_sql;

    return 0;
}

static int schema_table_list(void *ptr,
                             int ncols,
                             char **colvalues,
                             char **colnames)
{
    struct sqlite_metadata_callbacks *smc = (sqlite_metadata_callbacks *)ptr;
    string &schema_out = *((string *)smc->smc_userdata);
    auto_mem<char, sqlite3_free> create_sql;

    create_sql = sqlite3_mprintf("%s;\n", colvalues[1]);

    schema_out += create_sql;

    return 0;
}

static int schema_table_info(void *ptr,
                             int ncols,
                             char **colvalues,
                             char **colnames)
{
    return 0;
}

static int schema_foreign_key_list(void *ptr,
                                   int ncols,
                                   char **colvalues,
                                   char **colnames)
{
    return 0;
}

void dump_sqlite_schema(sqlite3 *db, std::string &schema_out)
{
    struct sqlite_metadata_callbacks schema_sql_meta_callbacks = {
        schema_collation_list,
        schema_db_list,
        schema_table_list,
        schema_table_info,
        schema_foreign_key_list,
        &schema_out
    };

    walk_sqlite_metadata(db, schema_sql_meta_callbacks);
}

void attach_sqlite_db(sqlite3 *db, const std::string &filename)
{
    static pcrecpp::RE db_name_converter("[^\\w]");

    auto_mem<sqlite3_stmt> stmt(sqlite3_finalize);

    if (sqlite3_prepare_v2(db,
                           "ATTACH DATABASE ? as ?",
                           -1,
                           stmt.out(),
                           NULL) != SQLITE_OK) {
        log_error("could not prepare DB attach statement -- %s",
            sqlite3_errmsg(db));
        return;
    }

    if (sqlite3_bind_text(stmt.in(), 1,
                          filename.c_str(), filename.length(),
                          SQLITE_TRANSIENT) != SQLITE_OK) {
        log_error("could not bind DB attach statement -- %s",
            sqlite3_errmsg(db));
        return;
    }

    size_t base_start = filename.find_last_of("/\\");
    string db_name;

    if (base_start == string::npos) {
        db_name = filename;
    }
    else {
        db_name = filename.substr(base_start + 1);
    }

    db_name_converter.GlobalReplace("_", &db_name);

    if (sqlite3_bind_text(stmt.in(), 2,
                          db_name.c_str(), db_name.length(),
                          SQLITE_TRANSIENT) != SQLITE_OK) {
        log_error("could not bind DB attach statement -- %s",
            sqlite3_errmsg(db));
        return;
    }

    if (sqlite3_step(stmt.in()) != SQLITE_DONE) {
        log_error("could not execute DB attach statement -- %s",
            sqlite3_errmsg(db));
        return;
    }
}

ssize_t sql_strftime(char *buffer, size_t buffer_size, time_t time, int millis,
    char sep)
{
    struct tm gmtm;
    int year, month, index = 0;

    secs2tm(&time, &gmtm);
    year = gmtm.tm_year + 1900;
    month = gmtm.tm_mon + 1;
    buffer[index++] = '0' + ((year / 1000) % 10);
    buffer[index++] = '0' + ((year /  100) % 10);
    buffer[index++] = '0' + ((year /   10) % 10);
    buffer[index++] = '0' + ((year /    1) % 10);
    buffer[index++] = '-';
    buffer[index++] = '0' + ((month / 10) % 10);
    buffer[index++] = '0' + ((month /  1) % 10);
    buffer[index++] = '-';
    buffer[index++] = '0' + ((gmtm.tm_mday / 10) % 10);
    buffer[index++] = '0' + ((gmtm.tm_mday /  1) % 10);
    buffer[index++] = sep;
    buffer[index++] = '0' + ((gmtm.tm_hour / 10) % 10);
    buffer[index++] = '0' + ((gmtm.tm_hour /  1) % 10);
    buffer[index++] = ':';
    buffer[index++] = '0' + ((gmtm.tm_min / 10) % 10);
    buffer[index++] = '0' + ((gmtm.tm_min /  1) % 10);
    buffer[index++] = ':';
    buffer[index++] = '0' + ((gmtm.tm_sec / 10) % 10);
    buffer[index++] = '0' + ((gmtm.tm_sec /  1) % 10);
    buffer[index++] = '.';
    buffer[index++] = '0' + ((millis / 100) % 10);
    buffer[index++] = '0' + ((millis /  10) % 10);
    buffer[index++] = '0' + ((millis /   1) % 10);
    buffer[index] = '\0';

    return index;
}

static void sqlite_logger(void *dummy, int code, const char *msg)
{
    lnav_log_level_t level;

    switch (code) {
    case SQLITE_OK:
        level = LOG_LEVEL_DEBUG;
        break;
#ifdef SQLITE_NOTICE
    case SQLITE_NOTICE:
        level = LOG_LEVEL_INFO;
        break;
#endif
#ifdef SQLITE_WARNING
    case SQLITE_WARNING:
        level = LOG_LEVEL_WARNING;
        break;
#endif
    default:
        level = LOG_LEVEL_ERROR;
        break;
    }

    log_msg(level, __FILE__, __LINE__, "%s", msg);
}

void sql_install_logger(void)
{
#ifdef SQLITE_CONFIG_LOG
    sqlite3_config(SQLITE_CONFIG_LOG, sqlite_logger, NULL);
#endif
}

bool sql_ident_needs_quote(const char *ident)
{
    for (int lpc = 0; ident[lpc]; lpc++) {
        if (!isalnum(ident[lpc]) && ident[lpc] != '_') {
            return true;
        }
    }

    return false;
}

char *sql_quote_ident(const char *ident)
{
    bool needs_quote = false;
    size_t quote_count = 0;
    char *retval;

    for (int lpc = 0; ident[lpc]; lpc++) {
        if ((lpc == 0 && isdigit(ident[lpc])) ||
                (!isalnum(ident[lpc]) && ident[lpc] != '_')) {
            needs_quote = true;
        }
        else if (ident[lpc] == '"') {
            quote_count += 1;
        }
    }

    if ((retval = (char *)sqlite3_malloc(
        strlen(ident) + quote_count * 2 + (needs_quote ? 2: 0) + 1)) == NULL) {
        retval = NULL;
    }
    else {
        char *curr = retval;

        if (needs_quote) {
            curr[0] = '"';
            curr += 1;
        }
        for (size_t lpc = 0; ident[lpc] != '\0'; lpc++) {
            switch (ident[lpc]) {
            case '"':
                curr[0] = '"';
                curr += 1;
            default:
                curr[0] = ident[lpc];
                break;
            }
            curr += 1;
        }
        if (needs_quote) {
            curr[0] = '"';
            curr += 1;
        }

        *curr = '\0';
    }

    return retval;
}

void sql_compile_script(sqlite3 *db,
                        const char *src_name,
                        const char *script_orig,
                        std::vector<sqlite3_stmt *> &stmts,
                        std::vector<std::string> &errors) {
    const char *script = script_orig;

    while (script != NULL && script[0]) {
        auto_mem<sqlite3_stmt> stmt(sqlite3_finalize);
        int line_number = 1;
        const char *tail;
        int retcode;

        while (isspace(*script) && script[0]) {
            script += 1;
        }
        for (const char *ch = script_orig; ch < script && ch[0]; ch++) {
            if (*ch == '\n') {
                line_number += 1;
            }
        }

        retcode = sqlite3_prepare_v2(db,
                                     script,
                                     -1,
                                     stmt.out(),
                                     &tail);
        log_debug("retcode %d  %p %p", retcode, script, tail);
        if (retcode != SQLITE_OK) {
            const char *errmsg = sqlite3_errmsg(db);
            auto_mem<char> full_msg;

            if (asprintf(full_msg.out(), "error:%s:%d:%s", src_name,
                         line_number, errmsg) == -1) {
                log_error("unable to allocate error message");
                break;
            }
            errors.push_back(full_msg.in());
            break;
        } else if (script == tail) {
            break;
        } else if (stmt == NULL) {

        } else {
            stmts.push_back(stmt.release());
        }

        script = tail;
    }
}

void sql_execute_script(sqlite3 *db,
                        const std::vector<sqlite3_stmt *> &stmts,
                        std::vector<std::string> &errors)
{
    map<string, string> lvars;

    for (sqlite3_stmt *stmt : stmts) {
        bool done = false;
        int param_count;

        sqlite3_clear_bindings(stmt);

        param_count = sqlite3_bind_parameter_count(stmt);
        for (int lpc = 0; lpc < param_count; lpc++) {
            const char *name;

            name = sqlite3_bind_parameter_name(stmt, lpc + 1);
            if (name[0] == '$') {
                map<string, string>::iterator iter;
                const char *env_value;

                if ((iter = lvars.find(&name[1])) != lvars.end()) {
                    sqlite3_bind_text(stmt, lpc + 1,
                                      iter->second.c_str(), -1,
                                      SQLITE_TRANSIENT);
                } else if ((env_value = getenv(&name[1])) != NULL) {
                    sqlite3_bind_text(stmt, lpc + 1,
                                      env_value, -1,
                                      SQLITE_TRANSIENT);
                } else {
                    sqlite3_bind_null(stmt, lpc + 1);
                }
            } else {
                sqlite3_bind_null(stmt, lpc + 1);
            }
        }
        while (!done) {
            int retcode = sqlite3_step(stmt);
            switch (retcode) {
                case SQLITE_OK:
                case SQLITE_DONE:
                    done = true;
                    break;

                case SQLITE_ROW: {
                    int ncols = sqlite3_column_count(stmt);

                    for (int lpc = 0; lpc < ncols; lpc++) {
                        const char *name = sqlite3_column_name(stmt, lpc);
                        const char *value = (const char *)
                                sqlite3_column_text(stmt, lpc);

                        lvars[name] = value;
                    }
                    break;
                }

                default: {
                    const char *errmsg;

                    errmsg = sqlite3_errmsg(db);
                    errors.push_back(errmsg);
                    break;
                }
            }
        }

        sqlite3_reset(stmt);
    }
}

void sql_execute_script(sqlite3 *db,
                        const char *src_name,
                        const char *script,
                        std::vector<std::string> &errors)
{
    vector<sqlite3_stmt *> stmts;

    sql_compile_script(db, src_name, script, stmts, errors);
    if (errors.empty()) {
        sql_execute_script(db, stmts, errors);
    }

    for (sqlite3_stmt *stmt : stmts) {
        sqlite3_finalize(stmt);
    }
}

static struct {
    int sqlite_type;
    const char *collator;
    const char *sample;
} TYPE_TEST_VALUE[] = {
        { SQLITE3_TEXT, NULL, "foobar" },
        { SQLITE_INTEGER, NULL, "123" },
        { SQLITE_FLOAT, NULL, "123.0" },
        { SQLITE_TEXT, "ipaddress", "127.0.0.1" },

        { SQLITE_NULL }
};

int guess_type_from_pcre(const string &pattern, const char **collator)
{
    try {
        pcrepp re(pattern.c_str());
        vector<int> matches;
        int retval = SQLITE3_TEXT;

        log_debug("guess pattern %s", pattern.c_str());

        *collator = NULL;
        for (int lpc = 0; TYPE_TEST_VALUE[lpc].sqlite_type != SQLITE_NULL; lpc++) {
            pcre_context_static<30> pc;
            pcre_input pi(TYPE_TEST_VALUE[lpc].sample);

            if (re.match(pc, pi, PCRE_ANCHORED) &&
                pc[0]->c_begin == 0 && pc[0]->length() == (int) pi.pi_length) {
                matches.push_back(lpc);
            }
        }

        log_debug("match size %d", matches.size());
        if (matches.size() == 1) {
            retval = TYPE_TEST_VALUE[matches.front()].sqlite_type;
            *collator = TYPE_TEST_VALUE[matches.front()].collator;
        }

        return retval;
    } catch (pcrepp::error &e) {
        return SQLITE3_TEXT;
    }
}

/* XXX figure out how to do this with the template */
void sqlite_close_wrapper(void *mem)
{
    sqlite3_close((sqlite3 *)mem);
}

int sqlite_authorizer(void *pUserData, int action_code, const char *detail1,
                      const char *detail2, const char *detail3,
                      const char *detail4)
{
    if (action_code == SQLITE_ATTACH)
    {
        return SQLITE_DENY;
    }
    return SQLITE_OK;
}

static string sql_keyword_re(void)
{
    string retval = "(?:";

    for (int lpc = 0; sql_keywords[lpc]; lpc++) {
        if (lpc > 0) {
            retval.append("|");
        }
        retval.append("\\b");
        retval.append(sql_keywords[lpc]);
        retval.append("\\b");
    }
    retval += ")";

    return retval;
}

string_attr_type SQL_KEYWORD_ATTR("sql_keyword");
string_attr_type SQL_IDENTIFIER_ATTR("sql_ident");
string_attr_type SQL_FUNCTION_ATTR("sql_func");
string_attr_type SQL_STRING_ATTR("sql_string");
string_attr_type SQL_OPERATOR_ATTR("sql_oper");
string_attr_type SQL_PAREN_ATTR("sql_paren");
string_attr_type SQL_GARBAGE_ATTR("sql_garbage");

void annotate_sql_statement(attr_line_t &al)
{
    static string keyword_re_str =
        R"(\A)" + sql_keyword_re() + R"(|\.schema|\.msgformats)";

    static struct {
        pcrepp re;
        string_attr_type_t type;
    } PATTERNS[] = {
        { {keyword_re_str.c_str(), PCRE_CASELESS}, &SQL_KEYWORD_ATTR },
        { {R"(\A'[^']*('(?:'[^']*')*|$))"}, &SQL_STRING_ATTR },
        { {R"(\A(\$?\b[a-z_]\w*)|\"([^\"]+)\"|\[([^\]]+)])", PCRE_CASELESS}, &SQL_IDENTIFIER_ATTR },
        { {R"(\A(\*|<|>|=|!|\-|\+|\|\|))"}, &SQL_OPERATOR_ATTR },
        { {R"(\A\(|\))"}, &SQL_PAREN_ATTR },
        { {R"(\A.)"}, &SQL_GARBAGE_ATTR },
    };

    static pcrepp ws_pattern(R"(\A\s+)");

    pcre_context_static<30> pc;
    pcre_input pi(al.get_string());
    string &line = al.get_string();
    string_attrs_t &sa = al.get_attrs();

    while (pi.pi_next_offset < line.length()) {
        if (ws_pattern.match(pc, pi, PCRE_ANCHORED)) {
            continue;
        }
        for (auto &pat : PATTERNS) {
            if (pat.re.match(pc, pi, PCRE_ANCHORED)) {
                pcre_context::capture_t *cap = pc.all();
                struct line_range lr(cap->c_begin, cap->c_end);

                sa.emplace_back(lr, pat.type);
                break;
            }
        }
    }

    string_attrs_t::const_iterator iter;
    int start = 0;

    while ((iter = find_string_attr(sa, &SQL_IDENTIFIER_ATTR, start)) != sa.end()) {
        string_attrs_t::const_iterator piter;
        bool found_open = false;
        ssize_t lpc;

        for (lpc = iter->sa_range.lr_end; lpc < line.length(); lpc++) {
            if (line[lpc] == '(') {
                found_open = true;
                break;
            } else if (!isspace(line[lpc])) {
                break;
            }
        }

        if (found_open) {
            ssize_t pstart = lpc + 1;
            int depth = 1;

            while (depth > 0 &&
                   (piter = find_string_attr(sa, &SQL_PAREN_ATTR, pstart)) != sa.end()) {
                if (line[piter->sa_range.lr_start] == '(') {
                    depth += 1;
                } else {
                    depth -= 1;
                }
                pstart = piter->sa_range.lr_end;
            }

            line_range func_range{iter->sa_range.lr_start};
            if (piter == sa.end()) {
                func_range.lr_end = line.length();
            } else {
                func_range.lr_end = piter->sa_range.lr_end;
            }
            sa.emplace_back(func_range, &SQL_FUNCTION_ATTR);
        }

        start = iter->sa_range.lr_end;
    }

    remove_string_attr(sa, &SQL_PAREN_ATTR);
}