path: root/libdbpp/tablepatch.cpp

#include "tablepatch.h"
#include "connection.h"
#include "modifycommand.h"
#include "selectcommand.h" // IWYU pragma: keep
#include "sqlWriter.h"
#include <boost/format.hpp>
#include <boost/format/format_fwd.hpp>
#include <buffer.h>
#include <memory>
#include <safeMapFind.h>
#include <utility>

DB::PatchResult
DB::Connection::patchTable(TablePatch * tp)
{
	if (tp->pk.empty()) {
		throw PatchCheckFailure();
	}
	if (!inTx()) {
		throw TransactionRequired();
	}
	TransactionScope tx(*this);
	bool ownedExpr = false;
	if (!tp->srcExpr && !tp->src.empty()) {
		tp->srcExpr = new DB::StaticSqlWriter(tp->src);
		ownedExpr = true;
	}
	DB::PatchResult r {tp->doDeletes ? patchDeletes(tp) : 0, tp->doUpdates ? patchUpdates(tp) : 0,
			tp->doInserts ? patchInserts(tp) : 0};
	if (ownedExpr) {
		delete tp->srcExpr;
		tp->srcExpr = nullptr;
	}
	return r;
}

template<typename Container>
static inline void
push(const boost::format &, typename Container::const_iterator &)
{
}

template<typename Container, typename Value, typename... Values>
static inline void
push(boost::format & f, typename Container::const_iterator & i, const Value & v, Values &&... vs)
{
	f % v(i);
	push<Container>(f, i, std::forward<Values>(vs)...);
}

template<typename Separator, typename Container, typename... Ps>
static inline unsigned int
appendIf(AdHoc::Buffer & buf, const Container & c,
		const std::function<bool(const typename Container::const_iterator)> & sel, const Separator & sep,
		const std::string & fmts, Ps &&... ps)
{
	auto fmt = AdHoc::Buffer::getFormat(fmts);
	unsigned int x = 0;
	for (auto i = c.begin(); i != c.end(); ++i) {
		if (sel(i)) {
			if (x > 0) {
				buf.appendbf("%s", sep);
			}
			push<Container>(fmt, i, std::forward<Ps>(ps)...);
			buf.append(fmt.str());
			x += 1;
		}
	}
	return x;
}

template<typename Separator, typename Container, typename... Ps>
static inline unsigned int
append(AdHoc::Buffer & buf, const Container & c, const Separator & sep, const std::string & fmts, Ps &&... ps)
{
	return appendIf(
			buf, c,
			[](auto) {
				return true;
			},
			sep, fmts, std::forward<Ps>(ps)...);
}

template<typename Container>
static inline typename Container::key_type
self(const typename Container::const_iterator & i)
{
	return *i;
}
#define selfCols self<decltype(DB::TablePatch::cols)>
#define isNotKey(tp) \
	[tp](auto i) { \
		return !AdHoc::containerContains((tp)->pk, *i); \
	}

static void
patchDeletesSelect(AdHoc::Buffer & toDelSql, DB::TablePatch * tp)
{
	toDelSql.append(" WHERE ");
	append(toDelSql, tp->pk, " AND ", " b.%s IS NULL", selfCols);
	if (tp->where) {
		toDelSql.append(" AND ");
		tp->where->writeSql(toDelSql);
	}
	if (tp->order) {
		toDelSql.append(" ORDER BY ");
		tp->order->writeSql(toDelSql);
	}
}

unsigned int
DB::Connection::patchDeletes(TablePatch * tp)
{
	if (tp->beforeDelete) {
		AdHoc::Buffer toDelSql;
		toDelSql.append("SELECT ");
		append(toDelSql, tp->cols, ", ", "a.%s", selfCols);
		toDelSql.appendbf(" FROM %s a LEFT OUTER JOIN ", tp->dest);
		tp->srcExpr->writeSql(toDelSql);
		toDelSql.append(" b ON ");
		append(toDelSql, tp->pk, " AND ", " a.%s = b.%s", selfCols, selfCols);
		patchDeletesSelect(toDelSql, tp);
		auto del = select(toDelSql);
		unsigned int offset = 0;
		tp->srcExpr->bindParams(del.get(), offset);
		if (tp->where) {
			tp->where->bindParams(del.get(), offset);
		}
		if (tp->order) {
			tp->order->bindParams(del.get(), offset);
		}
		tp->beforeDelete(del);
	}
	AdHoc::Buffer toDelSql;
	switch (bulkDeleteStyle()) {
		case BulkDeleteStyle::UsingSubSelect: {
			// -----------------------------------------------------------------
			// Build SQL to delete keys ----------------------------------------
			// -----------------------------------------------------------------
			if (tp->insteadOfDelete) {
				toDelSql.appendbf("UPDATE %s SET ", tp->dest);
				tp->insteadOfDelete->writeSql(toDelSql);
				toDelSql.append(" WHERE (");
			}
			else {
				toDelSql.appendbf("DELETE FROM %s WHERE (", tp->dest);
			}
			append(
					toDelSql, tp->pk, ", ", "%s.%s",
					[tp](auto) {
						return tp->dest;
					},
					selfCols);
			// -----------------------------------------------------------------
			// Build SQL to select keys to delete ------------------------------
			// -----------------------------------------------------------------
			toDelSql.append(") IN (SELECT ");
			append(toDelSql, tp->pk, ", ", "a.%s", selfCols);
			toDelSql.appendbf(" FROM %s a LEFT OUTER JOIN ", tp->dest);
			tp->srcExpr->writeSql(toDelSql);
			toDelSql.append(" b ON ");
			append(toDelSql, tp->pk, " AND ", " a.%s = b.%s", selfCols, selfCols);
			patchDeletesSelect(toDelSql, tp);
			toDelSql.append(")");
			break;
		}
		case BulkDeleteStyle::UsingUsingAlias:
		case BulkDeleteStyle::UsingUsing: {
			if (tp->insteadOfDelete) {
				toDelSql.appendbf("UPDATE %s a ", tp->dest);
			}
			else {
				toDelSql.appendbf("DELETE FROM %s USING %s a ",
						(bulkDeleteStyle() == BulkDeleteStyle::UsingUsingAlias ? "a" : tp->dest), tp->dest);
			}
			toDelSql.append(" LEFT OUTER JOIN ");
			tp->srcExpr->writeSql(toDelSql);
			toDelSql.append(" b ON ");
			append(toDelSql, tp->pk, " AND ", " a.%s = b.%s ", selfCols, selfCols);
			if (tp->insteadOfDelete) {
				tp->insteadOfDelete->writeSql(toDelSql);
			}
			patchDeletesSelect(toDelSql, tp);
			break;
		}
	}
	auto del = modify(toDelSql);
	unsigned int offset = 0;
	tp->srcExpr->bindParams(del.get(), offset);
	if (tp->insteadOfDelete) {
		tp->insteadOfDelete->bindParams(del.get(), offset);
	}
	if (tp->where) {
		tp->where->bindParams(del.get(), offset);
	}
	if (tp->order) {
		tp->order->bindParams(del.get(), offset);
	}
	return del->execute();
}

static void
patchUpdatesSelect(AdHoc::Buffer & updSql, DB::TablePatch * tp)
{
	updSql.append(" WHERE ");
	append(updSql, tp->pk, " AND ", " a.%s = b.%s ", selfCols, selfCols);
	updSql.append(" AND (");
	appendIf(updSql, tp->cols, isNotKey(tp), " OR ", " (((CASE WHEN (a.%s IS NULL AND b.%s IS NULL) THEN 1 ELSE 0 END) \
			+ (CASE WHEN(a.%s = b.%s) THEN 1 ELSE 0 END)) = 0)",
			selfCols, selfCols, selfCols, selfCols);
	updSql.append(")");
	if (tp->where) {
		updSql.append(" AND ");
		tp->where->writeSql(updSql);
	}
}

unsigned int
DB::Connection::patchUpdates(TablePatch * tp)
{
	if (tp->cols.size() == tp->pk.size()) {
		// Can't "change" anything... it's all part of the key
		return 0;
	}
	if (tp->beforeUpdate) {
		AdHoc::Buffer updSql;
		updSql.append("SELECT ");
		append(updSql, tp->pk, ", ", "a.%s", selfCols);
		appendIf(updSql, tp->cols, isNotKey(tp), "", ", a.%1% old_%1%", selfCols);
		appendIf(updSql, tp->cols, isNotKey(tp), "", ", b.%1% new_%1%", selfCols);
		updSql.appendbf(" FROM %s a, ", tp->dest);
		tp->srcExpr->writeSql(updSql);
		updSql.append(" b ");
		patchUpdatesSelect(updSql, tp);
		if (tp->order) {
			updSql.append(" ORDER BY ");
			tp->order->writeSql(updSql);
		}
		auto upd = select(updSql);
		unsigned int offset = 0;
		tp->srcExpr->bindParams(upd.get(), offset);
		if (tp->where) {
			tp->where->bindParams(upd.get(), offset);
		}
		if (tp->order) {
			tp->order->bindParams(upd.get(), offset);
		}
		tp->beforeUpdate(upd);
	}
	switch (bulkUpdateStyle()) {
		case BulkUpdateStyle::UsingFromSrc: {
			// -----------------------------------------------------------------
			// Build SQL for list of updates to perform ------------------------
			// -----------------------------------------------------------------
			AdHoc::Buffer updSql;
			updSql.appendbf("UPDATE %s a SET ", tp->dest);
			appendIf(updSql, tp->cols, isNotKey(tp), ", ", " %s = b.%s ", selfCols, selfCols);
			updSql.append(" FROM ");
			tp->srcExpr->writeSql(updSql);
			updSql.append(" b ");
			patchUpdatesSelect(updSql, tp);
			// -----------------------------------------------------------------
			// Execute the bulk update command ---------------------------------
			// -----------------------------------------------------------------
			auto upd = modify(updSql);
			unsigned int offset = 0;
			tp->srcExpr->bindParams(upd.get(), offset);
			if (tp->where) {
				tp->where->bindParams(upd.get(), offset);
			}
			return upd->execute(true);
		} break;
		case BulkUpdateStyle::UsingJoin: {
			// -----------------------------------------------------------------
			// Build SQL for list of updates to perform ------------------------
			// -----------------------------------------------------------------
			AdHoc::Buffer updSql;
			updSql.appendbf("UPDATE %s a, ", tp->dest);
			tp->srcExpr->writeSql(updSql);
			updSql.append(" b SET ");
			appendIf(updSql, tp->cols, isNotKey(tp), ", ", " a.%s = b.%s ", selfCols, selfCols);
			patchUpdatesSelect(updSql, tp);
			if (tp->order) {
				updSql.append(" ORDER BY ");
				tp->order->writeSql(updSql);
			}
			// -----------------------------------------------------------------
			// Execute the bulk update command ---------------------------------
			// -----------------------------------------------------------------
			auto upd = modify(updSql);
			unsigned int offset = 0;
			if (tp->where) {
				tp->where->bindParams(upd.get(), offset);
			}
			if (tp->order) {
				tp->order->bindParams(upd.get(), offset);
			}
			return upd->execute(true);
		}
	}
	return 0;
}

static void
patchInsertsSelect(AdHoc::Buffer & toInsSql, DB::TablePatch * tp)
{
	toInsSql.append("SELECT ");
	append(toInsSql, tp->cols, ", ", "b.%s", selfCols);
	toInsSql.append(" FROM  ");
	tp->srcExpr->writeSql(toInsSql);
	toInsSql.appendbf(" b LEFT OUTER JOIN %s a ON ", tp->dest);
	append(toInsSql, tp->pk, " AND ", " a.%s = b.%s", selfCols, selfCols);
	toInsSql.append(" WHERE ");
	append(toInsSql, tp->pk, " AND ", " a.%s IS NULL", selfCols);
	if (tp->order) {
		toInsSql.append(" ORDER BY ");
		tp->order->writeSql(toInsSql);
	}
}

unsigned int
DB::Connection::patchInserts(TablePatch * tp)
{
	if (tp->beforeInsert) {
		AdHoc::Buffer toInsSql;
		patchInsertsSelect(toInsSql, tp);
		auto ins = select(toInsSql);
		unsigned int offset = 0;
		tp->srcExpr->bindParams(ins.get(), offset);
		if (tp->order) {
			tp->order->bindParams(ins.get(), offset);
		}
		tp->beforeInsert(ins);
	}
	// -----------------------------------------------------------------
	// Build SQL for copying new records -------------------------------
	// -----------------------------------------------------------------
	AdHoc::Buffer toInsSql;
	toInsSql.appendbf("INSERT INTO %s(", tp->dest);
	append(toInsSql, tp->cols, ", ", "%s", selfCols);
	toInsSql.append(")\n");
	patchInsertsSelect(toInsSql, tp);
	auto ins = modify(toInsSql);
	unsigned int offset = 0;
	tp->srcExpr->bindParams(ins.get(), offset);
	if (tp->order) {
		tp->order->bindParams(ins.get(), offset);
	}
	return ins->execute();
}

std::string
DB::PatchCheckFailure::message() const noexcept
{
	return "Santiy checks failed: check table names and keys";
}