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use crate::myc::constants::{ColumnFlags, StatusFlags}; use crate::packet::PacketWriter; use crate::value::ToMysqlValue; use crate::writers; use crate::{Column, ErrorKind, StatementData}; use byteorder::WriteBytesExt; use std::borrow::Borrow; use std::collections::HashMap; use std::io::{self, Write}; /// Convenience type for responding to a client `USE <db>` command. pub struct InitWriter<'a, W: Write> { pub(crate) writer: &'a mut PacketWriter<W>, } impl<'a, W: Write + 'a> InitWriter<'a, W> { /// Tell client that database context has been changed pub fn ok(self) -> io::Result<()> { writers::write_ok_packet(self.writer, 0, 0, StatusFlags::empty()) } /// Tell client that there was a problem changing the database context. /// Although you can return any valid MySQL error code you probably want /// to keep it similar to the MySQL server and issue either a /// `ErrorKind::ER_BAD_DB_ERROR` or a `ErrorKind::ER_DBACCESS_DENIED_ERROR`. pub fn error<E>(self, kind: ErrorKind, msg: &E) -> io::Result<()> where E: Borrow<[u8]> + ?Sized, { writers::write_err(kind, msg.borrow(), self.writer) } } /// Convenience type for responding to a client `PREPARE` command. /// /// This type should not be dropped without calling /// [`reply`](struct.StatementMetaWriter.html#method.reply) or /// [`error`](struct.StatementMetaWriter.html#method.error). #[must_use] pub struct StatementMetaWriter<'a, W: Write> { pub(crate) writer: &'a mut PacketWriter<W>, pub(crate) stmts: &'a mut HashMap<u32, StatementData>, } impl<'a, W: Write + 'a> StatementMetaWriter<'a, W> { /// Reply to the client with the given meta-information. /// /// `id` is a statement identifier that the client should supply when it later wants to execute /// this statement. `params` is a set of [`Column`](struct.Column.html) descriptors for the /// parameters the client must provide when executing the prepared statement. `columns` is a /// second set of [`Column`](struct.Column.html) descriptors for the values that will be /// returned in each row then the statement is later executed. pub fn reply<PI, CI>(self, id: u32, params: PI, columns: CI) -> io::Result<()> where PI: IntoIterator<Item = &'a Column>, CI: IntoIterator<Item = &'a Column>, <PI as IntoIterator>::IntoIter: ExactSizeIterator, <CI as IntoIterator>::IntoIter: ExactSizeIterator, { let params = params.into_iter(); self.stmts.insert( id, StatementData { params: params.len() as u16, ..Default::default() }, ); writers::write_prepare_ok(id, params, columns, self.writer) } /// Reply to the client's `PREPARE` with an error. pub fn error<E>(self, kind: ErrorKind, msg: &E) -> io::Result<()> where E: Borrow<[u8]> + ?Sized, { writers::write_err(kind, msg.borrow(), self.writer) } } enum Finalizer { Ok { rows: u64, last_insert_id: u64 }, EOF, } /// Convenience type for providing query results to clients. /// /// This type should not be dropped without calling /// [`start`](struct.QueryResultWriter.html#method.start), /// [`completed`](struct.QueryResultWriter.html#method.completed), or /// [`error`](struct.QueryResultWriter.html#method.error). /// /// To send multiple resultsets, use /// [`RowWriter::finish_one`](struct.RowWriter.html#method.finish_one) and /// [`complete_one`](struct.QueryResultWriter.html#method.complete_one). These are similar to /// `RowWriter::finish` and `completed`, but both eventually yield back the `QueryResultWriter` so /// that another resultset can be sent. To indicate that no more resultset will be sent, call /// [`no_more_results`](struct.QueryResultWriter.html#method.no_more_results). All methods on /// `QueryResultWriter` (except `no_more_results`) automatically start a new resultset. The /// `QueryResultWriter` *may* be dropped without calling `no_more_results`, but in this case the /// program may panic if an I/O error occurs when sending the end-of-records marker to the client. /// To handle such errors, call `no_more_results` explicitly. #[must_use] pub struct QueryResultWriter<'a, W: Write> { // XXX: specialization instead? pub(crate) is_bin: bool, pub(crate) writer: &'a mut PacketWriter<W>, last_end: Option<Finalizer>, } impl<'a, W: Write> QueryResultWriter<'a, W> { pub(crate) fn new(writer: &'a mut PacketWriter<W>, is_bin: bool) -> Self { QueryResultWriter { is_bin, writer, last_end: None, } } fn finalize(&mut self, more_exists: bool) -> io::Result<()> { let mut status = StatusFlags::empty(); if more_exists { status.set(StatusFlags::SERVER_MORE_RESULTS_EXISTS, true); } match self.last_end.take() { None => Ok(()), Some(Finalizer::Ok { rows, last_insert_id, }) => writers::write_ok_packet(self.writer, rows, last_insert_id, status), Some(Finalizer::EOF) => writers::write_eof_packet(self.writer, status), } } /// Start a resultset response to the client that conforms to the given `columns`. /// /// Note that if no columns are emitted, any written rows are ignored. /// /// See [`RowWriter`](struct.RowWriter.html). pub fn start(mut self, columns: &'a [Column]) -> io::Result<RowWriter<'a, W>> { self.finalize(true)?; RowWriter::new(self, columns) } /// Send an empty resultset response to the client indicating that `rows` rows were affected by /// the query in this resultset. `last_insert_id` may be given to communiate an identifier for /// a client's most recent insertion. pub fn complete_one(mut self, rows: u64, last_insert_id: u64) -> io::Result<Self> { self.finalize(true)?; self.last_end = Some(Finalizer::Ok { rows, last_insert_id, }); Ok(self) } /// Send an empty resultset response to the client indicating that `rows` rows were affected by /// the query. `last_insert_id` may be given to communiate an identifier for a client's most /// recent insertion. pub fn completed(self, rows: u64, last_insert_id: u64) -> io::Result<()> { self.complete_one(rows, last_insert_id)?.no_more_results() } /// Reply to the client's query with an error. pub fn error<E>(mut self, kind: ErrorKind, msg: &E) -> io::Result<()> where E: Borrow<[u8]> + ?Sized, { self.finalize(true)?; writers::write_err(kind, msg.borrow(), self.writer) } /// Send the last bits of the last resultset to the client, and indicate that there are no more /// resultsets coming. pub fn no_more_results(mut self) -> io::Result<()> { self.finalize(false) } } impl<'a, W: Write> Drop for QueryResultWriter<'a, W> { fn drop(&mut self) { self.finalize(false).unwrap(); } } /// Convenience type for sending rows of a resultset to a client. /// /// Rows can either be written out one column at a time (using /// [`write_col`](struct.RowWriter.html#method.write_col) and /// [`end_row`](struct.RowWriter.html#method.end_row)), or one row at a time (using /// [`write_row`](struct.RowWriter.html#method.write_row)). /// /// This type *may* be dropped without calling /// [`write_row`](struct.RowWriter.html#method.write_row) or /// [`finish`](struct.RowWriter.html#method.finish). However, in this case, the program may panic /// if an I/O error occurs when sending the end-of-records marker to the client. To avoid this, /// call [`finish`](struct.RowWriter.html#method.finish) explicitly. #[must_use] pub struct RowWriter<'a, W: Write> { result: Option<QueryResultWriter<'a, W>>, bitmap_len: usize, data: Vec<u8>, columns: &'a [Column], // next column to write for the current row // NOTE: (ab)used to track number of *rows* for a zero-column resultset col: usize, finished: bool, } impl<'a, W> RowWriter<'a, W> where W: Write + 'a, { fn new( result: QueryResultWriter<'a, W>, columns: &'a [Column], ) -> io::Result<RowWriter<'a, W>> { let bitmap_len = (columns.len() + 7 + 2) / 8; let mut rw = RowWriter { result: Some(result), columns, bitmap_len, data: Vec::new(), col: 0, finished: false, }; rw.start()?; Ok(rw) } #[inline] fn start(&mut self) -> io::Result<()> { if !self.columns.is_empty() { writers::column_definitions(self.columns, self.result.as_mut().unwrap().writer)?; } Ok(()) } /// Write a value to the next column of the current row as a part of this resultset. /// /// If you do not call [`end_row`](struct.RowWriter.html#method.end_row) after the last row, /// any errors that occur when writing out the last row will be returned by /// [`finish`](struct.RowWriter.html#method.finish). If you do not call `finish` either, any /// errors will cause a panic when the `RowWriter` is dropped. /// /// Note that the row *must* conform to the column specification provided to /// [`QueryResultWriter::start`](struct.QueryResultWriter.html#method.start). If it does not, /// this method will return an error indicating that an invalid value type or specification was /// provided. pub fn write_col<T>(&mut self, v: T) -> io::Result<()> where T: ToMysqlValue, { if self.columns.is_empty() { return Ok(()); } if self.result.as_mut().unwrap().is_bin { if self.col == 0 { self.result.as_mut().unwrap().writer.write_u8(0x00)?; // leave space for nullmap self.data.resize(self.bitmap_len, 0); } let c = self .columns .get(self.col) .ok_or_else(|| { io::Error::new( io::ErrorKind::InvalidData, "row has more columns than specification", ) })? .borrow(); if v.is_null() { if c.colflags.contains(ColumnFlags::NOT_NULL_FLAG) { return Err(io::Error::new( io::ErrorKind::InvalidData, "given NULL value for NOT NULL column", )); } else { // https://web.archive.org/web/20170404144156/https://dev.mysql.com/doc/internals/en/null-bitmap.html // NULL-bitmap-byte = ((field-pos + offset) / 8) // NULL-bitmap-bit = ((field-pos + offset) % 8) self.data[(self.col + 2) / 8] |= 1u8 << ((self.col + 2) % 8); } } else { v.to_mysql_bin(&mut self.data, c)?; } } else { v.to_mysql_text(self.result.as_mut().unwrap().writer)?; } self.col += 1; Ok(()) } /// Indicate that no more column data will be written for the current row. pub fn end_row(&mut self) -> io::Result<()> { if self.columns.is_empty() { self.col += 1; return Ok(()); } if self.col != self.columns.len() { return Err(io::Error::new( io::ErrorKind::InvalidData, "row has fewer columns than specification", )); } if self.result.as_mut().unwrap().is_bin { self.result .as_mut() .unwrap() .writer .write_all(&self.data[..])?; self.data.clear(); } self.result.as_mut().unwrap().writer.end_packet()?; self.col = 0; Ok(()) } /// Write a single row as a part of this resultset. /// /// Note that the row *must* conform to the column specification provided to /// [`QueryResultWriter::start`](struct.QueryResultWriter.html#method.start). If it does not, /// this method will return an error indicating that an invalid value type or specification was /// provided. pub fn write_row<I, E>(&mut self, row: I) -> io::Result<()> where I: IntoIterator<Item = E>, E: ToMysqlValue, { if !self.columns.is_empty() { for v in row { self.write_col(v)?; } } self.end_row() } } impl<'a, W: Write + 'a> RowWriter<'a, W> { fn finish_inner(&mut self) -> io::Result<()> { if self.finished { return Ok(()); } self.finished = true; if !self.columns.is_empty() && self.col != 0 { self.end_row()?; } if self.columns.is_empty() { // response to no column query is always an OK packet // we've kept track of the number of rows in col (hacky, I know) self.result.as_mut().unwrap().last_end = Some(Finalizer::Ok { rows: self.col as u64, last_insert_id: 0, }); } else { // we wrote out at least one row self.result.as_mut().unwrap().last_end = Some(Finalizer::EOF); } Ok(()) } /// Indicate to the client that no more rows are coming. pub fn finish(self) -> io::Result<()> { self.finish_one()?.no_more_results() } /// End this resultset response, and indicate to the client that no more rows are coming. pub fn finish_one(mut self) -> io::Result<QueryResultWriter<'a, W>> { self.finish_inner()?; // we know that dropping self will see self.finished == true, // and so Drop won't try to use self.result. Ok(self.result.take().unwrap()) } } impl<'a, W: Write + 'a> Drop for RowWriter<'a, W> { fn drop(&mut self) { self.finish_inner().unwrap(); } }