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// value.rs // // This file is a part of the eXtremeDB source code // Copyright (c) 2020 McObject LLC // All Rights Reserved //! SQL values. //! //! This module implements the types necessary for passing the values to and //! from the *e*X*treme*DB SQL engine. //! //! # Passing Values to the SQL Engine //! //! The easiest way to pass values to queries and statements is to embed them //! in the SQL code itself: //! //! `INSERT INTO TestTable VALUES(1, 'SomeString');` //! //! However, this is often inconvenient. Furthermore, this approach requires the //! arguments to be sanitized to prevent trivial SQL injection attacks. //! //! Another approach is to pass the values as query parameters. The actual //! values in the SQL code are replaced with placeholders (`?`), and the //! arguments are passed by reference: //! //! ``` //! # use extremedb::connection::Connection; //! # use extremedb::database::{Database, Params}; //! # use extremedb::device::{Assignment, Device}; //! # use extremedb::runtime::Runtime; //! # use extremedb::sql::engine::{Engine, LocalEngine}; //! # use extremedb::Result; //! # use extremedb::device::util; //! # fn main() -> Result<()> { //! # let runtime = Runtime::start(vec![]); //! # let mut db_params = Params::new(); //! # db_params //! # .ddl_dict_size(32768) //! # .max_classes(100) //! # .max_indexes(1000); //! # let mut devs = util::DeviceContainer::new(); //! # let db = Database::open(&runtime, "test_db", None, devs.devices(), db_params)?; //! # let conn = Connection::new(&db)?; //! # let engine = LocalEngine::new(&conn)?; //! engine.execute_statement("CREATE TABLE TestTable(i integer, s string);", &[])?; //! engine.execute_statement("INSERT INTO TestTable(i, s) VALUES(?, ?);", &[&1, &"Hello"])?; //! engine.execute_statement("INSERT INTO TestTable(i, s) VALUES(?, ?);", &[&2, &"World"])?; //! # Ok(()) //! # } //! ``` //! //! Any type that implements the [`ToValue`] trait can be passed as a query //! argument. This module provides implementations of this trait for many //! common Rust types, as well as some helper types. //! //! ## Basic Types //! //! Basic types (booleans, integer and real numbers) are simply passed by //! reference: //! //! ``` //! # use extremedb::connection::Connection; //! # use extremedb::database::{Database, Params}; //! # use extremedb::device::{Assignment, Device}; //! # use extremedb::runtime::Runtime; //! # use extremedb::sql::engine::{Engine, LocalEngine}; //! # use extremedb::Result; //! # use extremedb::device::util; //! # fn main() -> Result<()> { //! # let runtime = Runtime::start(vec![]); //! # let mut db_params = Params::new(); //! # db_params //! # .ddl_dict_size(32768) //! # .max_classes(100) //! # .max_indexes(1000); //! # let mut devs = util::DeviceContainer::new(); //! # let db = Database::open(&runtime, "test_db", None, devs.devices(), db_params)?; //! # let conn = Connection::new(&db)?; //! # let engine = LocalEngine::new(&conn)?; //! engine.execute_statement( //! "CREATE TABLE TestTable(i integer, f float, b boolean);", //! &[], //! )?; //! engine.execute_statement( //! "INSERT INTO TestTable(i, f, b) VALUES(?, ?, ?);", //! &[&1, &123.45, &false], //! )?; //! # Ok(()) //! # } //! ``` //! //! ## Timestamps //! //! Timestamps can be passed as integers, as well as `std::time::SystemTime`. //! For example, this will create two rows with identical values: //! //! ``` //! # use extremedb::connection::Connection; //! # use extremedb::database::{Database, Params}; //! # use extremedb::device::{Assignment, Device}; //! # use extremedb::runtime::Runtime; //! # use extremedb::sql::engine::{Engine, LocalEngine}; //! # use extremedb::Result; //! # use extremedb::device::util; //! # use std::time::{self, SystemTime}; //! # fn main() -> Result<()> { //! # let runtime = Runtime::start(vec![]); //! # let mut db_params = Params::new(); //! # db_params //! # .ddl_dict_size(32768) //! # .max_classes(100) //! # .max_indexes(1000); //! # let mut devs = util::DeviceContainer::new(); //! # let db = Database::open(&runtime, "test_db", None, devs.devices(), db_params)?; //! # let conn = Connection::new(&db)?; //! # let engine = LocalEngine::new(&conn)?; //! engine.execute_statement("CREATE TABLE TestTable(ts timestamp);", &[])?; //! //! let now = SystemTime::now(); //! let now_int = now.duration_since(time::UNIX_EPOCH).unwrap().as_secs(); //! //! engine.execute_statement("INSERT INTO TestTable VALUES(?), (?);", &[&now, &now_int])?; //! # Ok(()) //! # } //! ``` //! //! ## Fixed-Width Numeric Values //! //! *e*X*treme*DB supports fixed-width numeric values. This module provides //! a wrapper type, [`Numeric`], to handle them. A fixed-width value `12.345` //! could be inserted like this: //! //! ``` //! # use extremedb::connection::Connection; //! # use extremedb::database::{Database, Params}; //! # use extremedb::device::{Assignment, Device}; //! # use extremedb::runtime::Runtime; //! # use extremedb::sql::engine::{Engine, LocalEngine}; //! # use extremedb::sql::value::Numeric; //! # use extremedb::Result; //! # use extremedb::device::util; //! # fn main() -> Result<()> { //! # let runtime = Runtime::start(vec![]); //! # let mut db_params = Params::new(); //! # db_params //! # .ddl_dict_size(32768) //! # .max_classes(100) //! # .max_indexes(1000); //! # let mut devs = util::DeviceContainer::new(); //! # let db = Database::open(&runtime, "test_db", None, devs.devices(), db_params)?; //! # let conn = Connection::new(&db)?; //! # let engine = LocalEngine::new(&conn)?; //! engine.execute_statement("CREATE TABLE TestTable(n numeric(5, 3));", &[])?; //! //! engine.execute_statement( //! "INSERT INTO TestTable VALUES(?);", //! &[&Numeric::new(12345, 3)], //! )?; //! # Ok(()) //! # } //! ``` //! //! ## Nullable Values //! //! Nullable values of type `T` can be passed as `Option<T>`: //! //! ``` //! # use extremedb::connection::Connection; //! # use extremedb::database::{Database, Params}; //! # use extremedb::device::{Assignment, Device}; //! # use extremedb::runtime::Runtime; //! # use extremedb::sql::engine::{Engine, LocalEngine}; //! # use extremedb::Result; //! # use extremedb::device::util; //! # fn main() -> Result<()> { //! # let runtime = Runtime::start(vec![]); //! # let mut db_params = Params::new(); //! # db_params //! # .ddl_dict_size(32768) //! # .max_classes(100) //! # .max_indexes(1000); //! # let mut devs = util::DeviceContainer::new(); //! # let db = Database::open(&runtime, "test_db", None, devs.devices(), db_params)?; //! # let conn = Connection::new(&db)?; //! # let engine = LocalEngine::new(&conn)?; //! engine.execute_statement("CREATE TABLE TestTable(i int);", &[])?; //! //! let non_null = Some(1); //! let null: Option<i32> = None; //! //! engine.execute_statement("INSERT INTO TestTable VALUES(?), (?);", &[&non_null, &null])?; //! # Ok(()) //! # } //! ``` //! //! ## Strings and Binary //! //! Strings and binary values can be passed as string slices and [`Binary`], //! respectively. Note that it is necessary to use the `Binary` helper type //! instead of `u8` slices: the latter are converted to [`Array`] instead. //! //! ``` //! # use extremedb::connection::Connection; //! # use extremedb::database::{Database, Params}; //! # use extremedb::device::{Assignment, Device}; //! # use extremedb::runtime::Runtime; //! # use extremedb::sql::engine::{Engine, LocalEngine}; //! # use extremedb::sql::value::Binary; //! # use extremedb::Result; //! # use extremedb::device::util; //! # fn main() -> Result<()> { //! # let runtime = Runtime::start(vec![]); //! # let mut db_params = Params::new(); //! # db_params //! # .ddl_dict_size(32768) //! # .max_classes(100) //! # .max_indexes(1000); //! # let mut devs = util::DeviceContainer::new(); //! # let db = Database::open(&runtime, "test_db", None, devs.devices(), db_params)?; //! # let conn = Connection::new(&db)?; //! # let engine = LocalEngine::new(&conn)?; //! engine.execute_statement("CREATE TABLE TestTable(s string, b varbinary);", &[])?; //! //! let s = "A string"; //! let b = Binary::new(b"Some binary data"); //! //! engine.execute_statement("INSERT INTO TestTable(s, b) VALUES(?, ?);", &[&s, &b])?; //! # Ok(()) //! # } //! ``` //! //! ## Arrays, Sequences, and Blobs //! //! Arrays, as well as sequences and blobs, are passed as slices of the //! appropriate types: //! //! ``` //! # use extremedb::connection::Connection; //! # use extremedb::database::{Database, Params}; //! # use extremedb::device::{Assignment, Device}; //! # use extremedb::runtime::Runtime; //! # use extremedb::sql::engine::{Engine, LocalEngine}; //! # use extremedb::Result; //! # use extremedb::device::util; //! # fn main() -> Result<()> { //! # let runtime = Runtime::start(vec![]); //! # let mut db_params = Params::new(); //! # db_params //! # .ddl_dict_size(32768) //! # .max_classes(100) //! # .max_indexes(1000); //! # let mut devs = util::DeviceContainer::new(); //! # let db = Database::open(&runtime, "test_db", None, devs.devices(), db_params)?; //! # let conn = Connection::new(&db)?; //! # let engine = LocalEngine::new(&conn)?; //! engine.execute_statement("CREATE TABLE TestTable(a array(int), b blob);", &[])?; //! //! let array: &[u32] = &[1, 2, 3, 4, 5]; //! let blob: &[u8] = &[0x01, 0x02, 0x03, 0x04, 0x05]; //! //! engine.execute_statement( //! "INSERT INTO TestTable(a, b) VALUES(?, ?);", //! &[&array, &blob], //! )?; //! # Ok(()) //! # } //! ``` //! //! [`ToValue`]: ./trait.ToValue.html //! [`Numeric`]: ./struct.Numeric.html //! [`Binary`]: ./struct.Binary.html //! //! # Receiving Values from the SQL Engine //! //! `SELECT` SQL queries usually produce *data sources*, which contain records //! (or rows). The records, in turn, contain *fields*, corresponding to the //! columns of the original SQL query. //! //! The contents of these fields are returned as *value references*, or //! instances of [`Ref`], whose lifetimes are bounded by their containing //! records' lifetimes. This means that the value references are transitional //! data structures, and the applications are not expected to try and retain //! them. Instead, they should convert the references to the native data types //! right away. //! //! [`Ref`] dereferences to [`Value`], which is a wrapper for the SQL engine's //! generic value type. It has methods that return the type of the contained //! value, as well as methods that convert it to native data types. The //! applications are expected to inspect the inner value type and call the //! appropriate conversion method. //! //! ## Basic Types //! //! Values can be converted to basic types using the appropriate conversion //! methods. Notice that all integer values are stored internally as `i64` //! by the SQL engine, and hence there is only one integer conversion method. //! //! ``` //! # use extremedb::connection::Connection; //! # use extremedb::database::{Database, Params}; //! # use extremedb::device::{Assignment, Device}; //! # use extremedb::runtime::Runtime; //! # use extremedb::sql::engine::{Engine, LocalEngine}; //! # use extremedb::sql::value; //! # use extremedb::Result; //! # use extremedb::device::util; //! # fn use_value(val: value::Ref) -> Result<()> { //! # assert_eq!(val.value_type()?, value::Type::Int8); //! if val.value_type()? == value::Type::Int8 { //! let i = val.to_i64()?; //! assert_eq!(i, 1); //! } //! # //! # Ok(()) //! # } //! # //! # fn main() -> Result<()> { //! # let runtime = Runtime::start(vec![]); //! # let mut db_params = Params::new(); //! # db_params //! # .ddl_dict_size(32768) //! # .max_classes(100) //! # .max_indexes(1000); //! # let mut devs = util::DeviceContainer::new(); //! # let db = Database::open(&runtime, "test_db", None, devs.devices(), db_params)?; //! # let conn = Connection::new(&db)?; //! # let engine = LocalEngine::new(&conn)?; //! # engine.execute_statement("CREATE TABLE TestTable(i int);", &[])?; //! # //! # engine.execute_statement("INSERT INTO TestTable VALUES(1);", &[])?; //! # //! # let ds = engine.execute_query("SELECT i FROM TestTable;", &[])?; //! # assert!(ds.is_some()); //! # let ds = ds.unwrap(); //! # let mut cur = ds.cursor()?; //! # { //! # assert_eq!(cur.advance()?, true); //! # assert!(cur.current_record().is_some()); //! # let rec = cur.current_record().unwrap(); //! # let val = rec.get_at(0)?; //! # use_value(val)?; //! # } //! # Ok(()) //! # } //! ``` //! //! ## Type Conversions //! //! SQL engine allows conversions between values of compatible types. //! Furthermore, most values can be converted to strings. For more details, //! refer to the *e*X*treme*DB C++ SQL API reference pages. //! //! ``` //! # use extremedb::connection::Connection; //! # use extremedb::database::{Database, Params}; //! # use extremedb::device::{Assignment, Device}; //! # use extremedb::runtime::Runtime; //! # use extremedb::sql::engine::{Engine, LocalEngine}; //! # use extremedb::sql::value; //! # use extremedb::Result; //! # use extremedb::device::util; //! # fn use_value(val: value::Ref) -> Result<()> { //! # assert_eq!(val.value_type()?, value::Type::Int8); //! if val.value_type()? == value::Type::Int8 { //! let i = val.to_i64()?; //! assert_eq!(i, 1); //! let f = val.to_real()?; //! assert_eq!(f, 1.0); //! let s = val.to_string()?; //! assert_eq!(s, "1"); //! } //! # //! # Ok(()) //! # } //! # //! # fn main() -> Result<()> { //! # let runtime = Runtime::start(vec![]); //! # let mut db_params = Params::new(); //! # db_params //! # .ddl_dict_size(32768) //! # .max_classes(100) //! # .max_indexes(1000); //! # let mut devs = util::DeviceContainer::new(); //! # let db = Database::open(&runtime, "test_db", None, devs.devices(), db_params)?; //! # let conn = Connection::new(&db)?; //! # let engine = LocalEngine::new(&conn)?; //! # engine.execute_statement("CREATE TABLE TestTable(i int);", &[])?; //! # //! # engine.execute_statement("INSERT INTO TestTable VALUES(1);", &[])?; //! # //! # let ds = engine.execute_query("SELECT i FROM TestTable;", &[])?; //! # assert!(ds.is_some()); //! # let ds = ds.unwrap(); //! # let mut cur = ds.cursor()?; //! # { //! # assert_eq!(cur.advance()?, true); //! # assert!(cur.current_record().is_some()); //! # let rec = cur.current_record().unwrap(); //! # let val = rec.get_at(0)?; //! # use_value(val)?; //! # } //! # Ok(()) //! # } //! ``` //! //! ## Getting References to the String and Binary Data //! //! String and binary conversion methods return owned values that contain //! copies of the value's data. This extra copying is not always desired, //! and can be avoided by using methods that return references to the //! underlying data. //! //! ``` //! # use extremedb::connection::Connection; //! # use extremedb::database::{Database, Params}; //! # use extremedb::device::{Assignment, Device}; //! # use extremedb::runtime::Runtime; //! # use extremedb::sql::engine::{Engine, LocalEngine}; //! # use extremedb::sql::value; //! # use extremedb::Result; //! # use extremedb::device::util; //! # fn use_value(val: value::Ref) -> Result<()> { //! # assert_eq!(val.value_type()?, value::Type::String); //! if val.value_type()? == value::Type::String { //! let s = val.as_str()?; //! assert_eq!(s, "Some string"); //! } //! # //! # Ok(()) //! # } //! # //! # fn main() -> Result<()> { //! # let runtime = Runtime::start(vec![]); //! # let mut db_params = Params::new(); //! # db_params //! # .ddl_dict_size(32768) //! # .max_classes(100) //! # .max_indexes(1000); //! # let mut devs = util::DeviceContainer::new(); //! # let db = Database::open(&runtime, "test_db", None, devs.devices(), db_params)?; //! # let conn = Connection::new(&db)?; //! # let engine = LocalEngine::new(&conn)?; //! # engine.execute_statement("CREATE TABLE TestTable(s string);", &[])?; //! # //! # engine.execute_statement("INSERT INTO TestTable VALUES('Some string');", &[])?; //! # //! # let ds = engine.execute_query("SELECT s FROM TestTable;", &[])?; //! # assert!(ds.is_some()); //! # let ds = ds.unwrap(); //! # let mut cur = ds.cursor()?; //! # { //! # assert_eq!(cur.advance()?, true); //! # assert!(cur.current_record().is_some()); //! # let rec = cur.current_record().unwrap(); //! # let val = rec.get_at(0)?; //! # use_value(val)?; //! # } //! # Ok(()) //! # } //! ``` //! //! ## Arrays, Sequences, and Blobs //! //! Generic values that contain arrays, sequences, and blobs have to be //! converted to the appropriate specific types — [`Array`], [`Sequence`], //! and [`Blob`], respectively. For example, an array containing values `1`, //! `2`, and `3`, could be handled like this: //! //! ``` //! # use extremedb::connection::Connection; //! # use extremedb::database::{Database, Params}; //! # use extremedb::device::{Assignment, Device}; //! # use extremedb::runtime::Runtime; //! # use extremedb::sql::engine::{Engine, LocalEngine}; //! # use extremedb::sql::value; //! # use extremedb::Result; //! # use extremedb::device::util; //! # fn use_value(val: value::Ref) -> Result<()> { //! # assert_eq!(val.value_type()?, value::Type::Array); //! if val.value_type()? == value::Type::Array { //! let arr = val.as_array()?; //! # assert_eq!(arr.elem_type()?, value::Type::Int4); //! # assert_eq!(arr.len()?, 3); //! if arr.elem_type()? == value::Type::Int4 { //! assert_eq!(arr.get_at(0)?.to_i64()?, 1); //! assert_eq!(arr.get_at(1)?.to_i64()?, 2); //! assert_eq!(arr.get_at(2)?.to_i64()?, 3); //! } //! } //! # //! # Ok(()) //! # } //! # //! # fn main() -> Result<()> { //! # let runtime = Runtime::start(vec![]); //! # let mut db_params = Params::new(); //! # db_params //! # .ddl_dict_size(32768) //! # .max_classes(100) //! # .max_indexes(1000); //! # let mut devs = util::DeviceContainer::new(); //! # let db = Database::open(&runtime, "test_db", None, devs.devices(), db_params)?; //! # let conn = Connection::new(&db)?; //! # let engine = LocalEngine::new(&conn)?; //! # engine.execute_statement("CREATE TABLE TestTable(a array(int));", &[])?; //! # //! # engine.execute_statement("INSERT INTO TestTable VALUES([1, 2, 3]);", &[])?; //! # //! # let ds = engine.execute_query("SELECT a FROM TestTable;", &[])?; //! # assert!(ds.is_some()); //! # let ds = ds.unwrap(); //! # let mut cur = ds.cursor()?; //! # { //! # assert_eq!(cur.advance()?, true); //! # assert!(cur.current_record().is_some()); //! # let rec = cur.current_record().unwrap(); //! # let val = rec.get_at(0)?; //! # use_value(val)?; //! # } //! # Ok(()) //! # } //! ``` //! //! [`Ref`]: ./struct.Ref.html //! [`Value`]: ./struct.Value.html //! [`Array`]: ./struct.Array.html //! [`Sequence`]: ./struct.Sequence.html //! [`Blob`]: ./struct.Blob.html //! use std::convert::TryFrom; use std::ffi::c_void; use std::fmt::{Display, Error as FmtError, Formatter}; use std::marker::PhantomData; use std::mem::MaybeUninit; use std::ops::Deref; use std::ptr; use std::slice; use std::str; use std::time::{Duration, SystemTime, UNIX_EPOCH}; use crate::runtime::options; use crate::sql::allocator::{self, Ref as AllocatorRef}; use crate::sql::{mcosql_error_code, result_from_code}; use crate::{exdb_sys, Error, Result}; use exdb_sys::mcosql_column_type; /// The type of a generic SQL value. #[derive(Clone, Copy, Debug, PartialEq)] pub enum Type { /// A `null` value. Null = mcosql_column_type::CT_NULL as isize, /// A boolean value. Bool = mcosql_column_type::CT_BOOL as isize, /// A signed 8-bit integer. Int1 = mcosql_column_type::CT_INT1 as isize, /// A signed 16-bit integer. Int2 = mcosql_column_type::CT_INT2 as isize, /// A signed 32-bit integer. Int4 = mcosql_column_type::CT_INT4 as isize, /// A signed 64-bit integer. Int8 = mcosql_column_type::CT_INT8 as isize, /// An unsigned 8-bit integer. UInt1 = mcosql_column_type::CT_UINT1 as isize, /// An unsigned 16-bit integer. UInt2 = mcosql_column_type::CT_UINT2 as isize, /// An unsigned 32-bit integer. UInt4 = mcosql_column_type::CT_UINT4 as isize, /// An unsigned 64-bit integer. UInt8 = mcosql_column_type::CT_UINT8 as isize, /// A 32-bit floating point value. Real4 = mcosql_column_type::CT_REAL4 as isize, /// A 64-bit floating point value. Real8 = mcosql_column_type::CT_REAL8 as isize, /// A timestamp. Time = mcosql_column_type::CT_TIME as isize, /// A fixed-width numeric value. Numeric = mcosql_column_type::CT_NUMERIC as isize, // Unicode = mcosql_column_type::CT_UNICODE as isize, /// A variable-length string. String = mcosql_column_type::CT_STRING as isize, /// A variable-length byte array. Binary = mcosql_column_type::CT_BINARY as isize, // Reference = mcosql_column_type::CT_REFERENCE as isize, /// An array of values. Array = mcosql_column_type::CT_ARRAY as isize, //Struct = mcosql_column_type::CT_STRUCT as isize, /// A blob. Blob = mcosql_column_type::CT_BLOB as isize, // DataSource = mcosql_column_type::CT_DATA_SOURCE as isize, // List = mcosql_column_type::CT_LIST as isize, /// A sequence. Sequence = mcosql_column_type::CT_SEQUENCE as isize, } impl Type { pub(crate) fn from_mco(v: mcosql_column_type::Type) -> Option<Self> { match v { mcosql_column_type::CT_NULL => Some(Type::Null), mcosql_column_type::CT_BOOL => Some(Type::Bool), mcosql_column_type::CT_INT1 => Some(Type::Int1), mcosql_column_type::CT_INT2 => Some(Type::Int2), mcosql_column_type::CT_INT4 => Some(Type::Int4), mcosql_column_type::CT_INT8 => Some(Type::Int8), mcosql_column_type::CT_UINT1 => Some(Type::UInt1), mcosql_column_type::CT_UINT2 => Some(Type::UInt2), mcosql_column_type::CT_UINT4 => Some(Type::UInt4), mcosql_column_type::CT_UINT8 => Some(Type::UInt8), mcosql_column_type::CT_REAL4 => Some(Type::Real4), mcosql_column_type::CT_REAL8 => Some(Type::Real8), mcosql_column_type::CT_TIME => Some(Type::Time), mcosql_column_type::CT_NUMERIC => Some(Type::Numeric), mcosql_column_type::CT_STRING => Some(Type::String), mcosql_column_type::CT_BINARY => Some(Type::Binary), mcosql_column_type::CT_ARRAY => Some(Type::Array), mcosql_column_type::CT_BLOB => Some(Type::Blob), mcosql_column_type::CT_SEQUENCE => Some(Type::Sequence), _ => None, } } } /// A generic SQL value. /// /// This struct is a wrapper for the C++ SQL API's `Value` class. It is /// currently impossible to instantiate this structure from the application /// code. Instead, applications pass values of types that implement the /// [`ToValue`] trait to the SQL engine. Applications will only deal with /// `Value`s they receive from the SQL engine. /// /// # Memory Management /// /// Internally, SQL values are always produced by the SQL engine's custom /// allocators, and thus cannot outlive them. Consequently, they do not quite /// follow Rust's memory management rules. Dropping a `Value` does not /// free its memory instantly; it is only done when the allocator /// is destroyed. However, most `Value`s returned by the SQL API are wrapped in /// a [`Ref`]. A `Ref` releases the `Value` it refers to when it goes /// out of scope. /// /// [`ToValue`]: ./trait.ToValue.html /// [`Ref`]: ./struct.Ref.html #[repr(transparent)] pub struct Value<'a> { alloc: PhantomData<&'a AllocatorRef<'a>>, h: exdb_sys::mcosql_rs_value, } impl<'a> Value<'a> { fn from_handle(h: exdb_sys::mcosql_rs_value, _allocator: AllocatorRef<'a>) -> Self { Value { alloc: PhantomData, h, } } fn new_null() -> Result<Self> { let mut h = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_value_create_null(h.as_mut_ptr()) }).and(Ok( Value { alloc: PhantomData, h: unsafe { h.assume_init() }, }, )) } fn new_bool(val: bool) -> Result<Self> { let ival = if val { 1 } else { 0 }; let mut h = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_value_create_bool(ival, h.as_mut_ptr()) }) .and(Ok(Value { alloc: PhantomData, h: unsafe { h.assume_init() }, })) } fn new_int(val: i64, alloc: AllocatorRef<'a>) -> Result<Self> { let mut h = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_value_create_int(alloc.h, val, h.as_mut_ptr()) }) .and(Ok(Value { alloc: PhantomData, h: unsafe { h.assume_init() }, })) } fn new_real(val: f64, alloc: AllocatorRef<'a>) -> Result<Self> { let mut h = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_value_create_real(alloc.h, val, h.as_mut_ptr()) }) .and(Ok(Value { alloc: PhantomData, h: unsafe { h.assume_init() }, })) } fn new_string(val: &str, alloc: AllocatorRef<'a>) -> Result<Self> { let mut h = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_value_create_string( alloc.h, val.as_ptr() as *const i8, val.len() as exdb_sys::size_t, h.as_mut_ptr(), ) }) .and(Ok(Value { alloc: PhantomData, h: unsafe { h.assume_init() }, })) } fn new_binary(val: &[u8], alloc: AllocatorRef<'a>) -> Result<Self> { let mut h = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_value_create_binary( alloc.h, val.as_ptr() as *const c_void, val.len() as exdb_sys::size_t, h.as_mut_ptr(), ) }) .and(Ok(Value { alloc: PhantomData, h: unsafe { h.assume_init() }, })) } fn new_date_time(val: &SystemTime, alloc: AllocatorRef<'a>) -> Result<Self> { let dur = val .duration_since(UNIX_EPOCH) .or(Err(Error::new_sql(mcosql_error_code::INVALID_TYPE_CAST)))?; let prec = unsafe { exdb_sys::mco_runtime_getoption( options::mco_rt_defines::keys::MCO_RT_OPTION_DATETIME_PRECISION as i32, ) } as u128; let val; if prec >= 1_000_000_000 { val = dur.as_nanos() * (prec / 1_000_000_000); } else if prec >= 1_000_000 { val = dur.as_micros() * (prec / 1_000_000); } else if prec >= 1_000 { val = dur.as_millis() * (prec / 1_000); } else { val = (dur.as_secs() as u128) * prec; } let val = u64::try_from(val).or(Err(Error::new_sql(mcosql_error_code::INVALID_TYPE_CAST)))?; let mut h = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_value_create_datetime(alloc.h, val, h.as_mut_ptr()) }) .and(Ok(Value { alloc: PhantomData, h: unsafe { h.assume_init() }, })) } fn new_numeric(val_scaled: i64, prec: usize, alloc: AllocatorRef<'a>) -> Result<Self> { let mut h = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_value_create_numeric( alloc.h, val_scaled, prec as exdb_sys::size_t, h.as_mut_ptr(), ) }) .and(Ok(Value { alloc: PhantomData, h: unsafe { h.assume_init() }, })) } /// Returns the type of the contained value. pub fn value_type(&self) -> Result<Type> { let mut ty = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_value_type(self.h, ty.as_mut_ptr()) }).and( Type::from_mco(unsafe { ty.assume_init() }) .ok_or(Error::new_sql(mcosql_error_code::RUNTIME_ERROR)), ) } /// For non-scalar types, returns the size of the data. /// /// Depending on the contained type, returns: /// /// - `String` and `Binary`: length of the string or binary string; /// - `Array`: number of elements. pub fn size(&self) -> Result<usize> { let mut ret = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_value_size(self.h, ret.as_mut_ptr()) }) .and(Ok(unsafe { ret.assume_init() } as usize)) } /// Returns `true` if the value is an SQL `null` value. pub fn is_null(&self) -> bool { 0 != unsafe { exdb_sys::mcosql_rs_value_is_null(self.h) } } /// Returns `true` if the value is a boolean `true` value, or a non-zero /// integer. pub fn is_true(&self) -> bool { 0 != unsafe { exdb_sys::mcosql_rs_value_is_true(self.h) } } /// Casts the value to `i64`. /// /// Strings are parsed and converted, if possible; otherwise an error is /// returned. pub fn to_i64(&self) -> Result<i64> { let mut val = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_value_int(self.h, val.as_mut_ptr()) }) .and(Ok(unsafe { val.assume_init() })) } /// Casts the value to `f64`. /// /// Strings are parsed and converted, if possible; otherwise an error is /// returned. pub fn to_real(&self) -> Result<f64> { let mut val = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_value_real(self.h, val.as_mut_ptr()) }) .and(Ok(unsafe { val.assume_init() })) } /// Casts the value to the number of system ticks elapsed since /// the beginning of the epoch. /// /// String values are parsed using `strptime()` where available, or a /// compatible custom function. pub fn to_date_time(&self) -> Result<u64> { let mut val = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_value_datetime(self.h, val.as_mut_ptr()) }) .and(Ok(unsafe { val.assume_init() })) } /// Casts the value to the number of system ticks elapsed since /// the beginning of the epoch, and converts the resulting value to /// `std::time::SystemTime`. pub fn to_system_time(&self) -> Result<SystemTime> { let prec = unsafe { exdb_sys::mco_runtime_getoption( options::mco_rt_defines::keys::MCO_RT_OPTION_DATETIME_PRECISION as i32, ) } as u64; let dt = self.to_date_time()?; let dur; if prec >= 1_000_000_000 { dur = Duration::from_nanos(dt / (prec / 1_000_000_000)); } else if prec >= 1_000_000 { dur = Duration::from_micros(dt / (prec / 1_000_000)); } else if prec >= 1_000 { dur = Duration::from_millis(dt / (prec / 1_000)); } else { dur = Duration::from_secs(dt / prec); } UNIX_EPOCH .checked_add(dur) .ok_or(Error::new_sql(mcosql_error_code::INVALID_TYPE_CAST)) } /// Returns the contained fixed-width numeric value, if any, or an error. pub fn to_numeric(&self) -> Result<Numeric> { if self.value_type()? == Type::Numeric { let mut val = 0i64; let mut prec: exdb_sys::size_t = 0; result_from_code(unsafe { exdb_sys::mcosql_rs_value_numeric(self.h, &mut val, &mut prec) }) .and( Numeric::new(val, prec as usize) .ok_or(Error::new_sql(mcosql_error_code::INVALID_TYPE_CAST)), ) } else { Err(Error::new_sql(mcosql_error_code::INVALID_TYPE_CAST)) } } /// Converts the value to the string representation. pub fn to_string(&self) -> Result<String> { let alloc = allocator::Owned::new()?; let mut h = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_value_string_ref(self.h, alloc.h, h.as_mut_ptr()) })?; let sref = Ref::from_handle(unsafe { h.assume_init() }, &alloc); let data = unsafe { slice::from_raw_parts(sref.pointer()? as *const u8, sref.size()?) }; let v = data.to_vec(); String::from_utf8(v).or(Err(Error::new_sql(mcosql_error_code::INVALID_TYPE_CAST))) } /// Returns a string slice pointing to the contents of a `String` value, /// or an error if the value is not a `String`. pub fn as_str(&self) -> Result<&str> { if self.value_type()? != Type::String { Err(Error::new_sql(mcosql_error_code::INVALID_TYPE_CAST)) } else { let data = unsafe { slice::from_raw_parts(self.pointer()? as *const u8, self.size()?) }; str::from_utf8(data).or(Err(Error::new_sql(mcosql_error_code::INVALID_TYPE_CAST))) } } /// Returns a copy of the bytes of a string or a binary value. pub fn to_binary(&self) -> Result<Vec<u8>> { let alloc = allocator::Owned::new()?; let mut h = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_value_binary(self.h, alloc.h, h.as_mut_ptr()) })?; let sref = Ref::from_handle(unsafe { h.assume_init() }, &alloc); let data = unsafe { slice::from_raw_parts(sref.pointer()? as *const u8, sref.size()?) }; Ok(data.to_vec()) } /// Returns a byte slice pointing to the contents of a `Binary` value, /// or an error if the value is not a `Binary`. pub fn as_bytes(&self) -> Result<&[u8]> { if self.value_type()? != Type::Binary { Err(Error::new_sql(mcosql_error_code::INVALID_TYPE_CAST)) } else { Ok(unsafe { slice::from_raw_parts(self.pointer()? as *const u8, self.size()?) }) } } /// Casts the value to `Array` if it has the `Array` type; returns /// an error otherwise. pub fn as_array(&self) -> Result<&Array> { if let Type::Array = self.value_type()? { Ok(unsafe { &*(self as *const Value as *const Array) }) } else { Err(Error::new_sql(mcosql_error_code::INVALID_TYPE_CAST)) } } /// Casts the value to `Sequence` if it has the `Sequence` type; returns /// an error otherwise. pub fn as_sequence(&self) -> Result<&Sequence> { if let Type::Sequence = self.value_type()? { Ok(unsafe { &*(self as *const Value as *const Sequence) }) } else { Err(Error::new_sql(mcosql_error_code::INVALID_TYPE_CAST)) } } /// Casts the value to `Blob` if it has the `Blob` type; returns /// an error otherwise. pub fn as_blob(&self) -> Result<&Blob> { if let Type::Blob = self.value_type()? { Ok(unsafe { &*(self as *const Value as *const Blob) }) } else { Err(Error::new_sql(mcosql_error_code::INVALID_TYPE_CAST)) } } unsafe fn pointer(&self) -> Result<*const c_void> { let mut p = MaybeUninit::uninit(); result_from_code(exdb_sys::mcosql_rs_value_ptr(self.h, p.as_mut_ptr())) .and(Ok(p.assume_init())) } // Highly unsafe: must be released using the allocator which was used to allocate the value; // leaves the value in the invalid state. unsafe fn release(&self, alloc: AllocatorRef) -> Result<()> { result_from_code(exdb_sys::mcosql_rs_value_release(alloc.h, self.h)) } } impl<'a> From<Array<'a>> for Value<'a> { fn from(array: Array<'a>) -> Self { array.val } } impl<'a> From<Sequence<'a>> for Value<'a> { fn from(seq: Sequence<'a>) -> Self { seq.val } } impl<'a> From<Blob<'a>> for Value<'a> { fn from(blob: Blob<'a>) -> Self { blob.val } } /// An SQL value reference. /// /// In addition to the value itself, a value reference holds a reference to the /// value's allocator, making it possible to release the value when the /// reference goes out of scope. pub struct Ref<'a> { r: exdb_sys::mcosql_rs_value_ref, owner: PhantomData<&'a ()>, } impl<'a> Ref<'a> { pub(crate) fn from_handle<T>(r: exdb_sys::mcosql_rs_value_ref, _owner: &'a T) -> Self { Ref { r, owner: PhantomData, } } fn allocator(&'a self) -> AllocatorRef<'a> { AllocatorRef::from_handle(self.r.allocator, self) } fn defused_clone(&'a self) -> Ref<'a> { Ref { r: exdb_sys::mcosql_rs_value_ref { allocator: ptr::null_mut(), ref_: self.r.ref_, }, owner: PhantomData, } } fn is_null_ref(&self) -> bool { self.r.ref_.is_null() } fn release_value(&mut self) { if !self.is_null_ref() && !self.r.allocator.is_null() { let alloc = self.allocator(); let res = unsafe { self.release(alloc) }; debug_assert!(res.is_ok()); } self.r.ref_ = ptr::null_mut(); } // Unsafe: new value must be allocated by the same allocator and produced by the same owner; // no other references to the value must be held. unsafe fn replace_value(&mut self, new_value: exdb_sys::mcosql_rs_value) { self.release_value(); self.r.ref_ = new_value; } } impl<'a> Deref for Ref<'a> { type Target = Value<'a>; fn deref(&self) -> &Self::Target { assert!(!self.is_null_ref()); unsafe { &*(&self.r.ref_ as *const exdb_sys::mcosql_rs_value as *const Value) } } } impl<'a> Drop for Ref<'a> { fn drop(&mut self) { self.release_value(); } } /// An SQL array. /// /// An *e*X*treme*DB SQL array contains [`Value`]s of the same type, and /// exposes public methods to access them. /// /// A [`Value`] can only be converted into an `Array` if it has the `Array` /// type. The opposite conversion is always possible. /// /// [`Value`]: ./struct.Value.html // WARNING: must have same repr as Value! Value is cast to Array in Value::as_array #[repr(transparent)] pub struct Array<'a> { val: Value<'a>, } impl<'a> Array<'a> { fn new<T: ArrayElem>(items: &[T], alloc: AllocatorRef<'a>) -> Result<Self> { let mut h = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_value_create_array( alloc.h, T::static_type() as mcosql_column_type::Type, items.len() as exdb_sys::size_t, h.as_mut_ptr(), ) })?; let mut ret = Array { val: Value::from_handle(unsafe { h.assume_init() }, alloc), }; ret.set_body(items).and(Ok(ret)) } fn is_plain(&self) -> bool { let mut plain = 0i32; let rc = unsafe { exdb_sys::mcosql_rs_array_is_plain(self.val.h, &mut plain) }; // Not expected to fail unless something is really wrong debug_assert_eq!(mcosql_error_code::SQL_OK, rc); plain != 0 } /// Returns the type of the array's elements. pub fn elem_type(&self) -> Result<Type> { let mut ty = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_array_elem_type(self.val.h, ty.as_mut_ptr()) }) .and( Type::from_mco(unsafe { ty.assume_init() }) .ok_or(Error::new_sql(mcosql_error_code::RUNTIME_ERROR)), ) } /// Returns the length of the array. pub fn len(&self) -> Result<usize> { self.val.size() } /// Returns the element at the given index. pub fn get_at(&self, at: usize) -> Result<Ref> { let mut h = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_array_get_at(self.val.h, at as exdb_sys::size_t, h.as_mut_ptr()) }) .and(Ok(Ref::from_handle(unsafe { h.assume_init() }, self))) } fn allocator(&'a self) -> Result<AllocatorRef<'a>> { let mut alloc_h = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_array_allocator(self.val.h, alloc_h.as_mut_ptr()) }) .and(Ok(AllocatorRef::from_handle( unsafe { alloc_h.assume_init() }, self, ))) } fn set_body<T: ArrayElem>(&mut self, body: &[T]) -> Result<()> { if body.len() != self.val.size()? { // The caller is currently required to set the entire body. Err(Error::new_sql(mcosql_error_code::RUNTIME_ERROR)) } else { if self.is_plain() { self.set_body_plain(body) } else { self.set_body_values(body) } } } fn set_body_values<T: ArrayElem>(&mut self, body: &[T]) -> Result<()> { // Sanity check: must not be called for plain arrays. debug_assert!(!self.is_plain()); // Get the reference to the array's own allocator to ensure that values live // as long as the array. let alloc = self.allocator()?; for i in 0..body.len() { // Values do not implement Drop. Hence, the handle of the allocated value will // remain valid when val goes out of scope. let val = body[i].to_value(alloc)?; result_from_code(unsafe { exdb_sys::mcosql_rs_array_set_at(self.val.h, i as exdb_sys::size_t, val.h) })?; } Ok(()) } fn set_body_plain<T: ArrayElem>(&mut self, body: &[T]) -> Result<()> { // Sanity check: must only be called for plain arrays. debug_assert!(self.is_plain()); result_from_code(unsafe { exdb_sys::mcosql_rs_array_set_body( self.val.h, body.as_ptr() as *const c_void, body.len() as exdb_sys::size_t, ) }) } } impl<'a> TryFrom<Value<'a>> for Array<'a> { type Error = Error; fn try_from(value: Value<'a>) -> std::result::Result<Self, Self::Error> { if let Type::Array = value.value_type()? { Ok(Array { val: value }) } else { Err(Error::new_sql(mcosql_error_code::INVALID_TYPE_CAST)) } } } /// A trait for converting a value to a SQL [`Value`]. /// /// Since it is currently impossible to instantiate a `Value` in the application /// code, this trait should be considered sealed. /// /// This module implements the `ToValue` trait for the common Rust types /// supported by the *e*X*treme*DB SQL engine. Any type that implements this /// trait can be passed as a parameter to the SQL statement execution methods. /// /// [`Value`]: ./trait.ToValue.html pub trait ToValue { #[doc(hidden)] fn to_value<'a>(&self, alloc: AllocatorRef<'a>) -> Result<Value<'a>>; } /// An SQL sequence. /// /// An *e*X*treme*DB SQL sequence contains [`Value`]s of the same type, and /// exposes public methods to access them. /// /// Sequences are conceptually different from arrays. Because of a different /// internal implementation, their elements are accessed using an iterator, /// instead of the getter methods. /// /// A [`Value`] can only be converted into a `Sequence` if it has the `Sequence` /// type. The opposite conversion is always possible. /// /// [`Value`]: ./struct.Value.html // WARNING: must have same repr as Value! Value is cast to Sequence in Value::as_sequence #[repr(transparent)] pub struct Sequence<'a> { val: Value<'a>, } impl<'a> Sequence<'a> { /// Returns the type of the sequence elements. pub fn elem_type(&self) -> Result<Type> { let mut ty = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_seq_elem_type(self.val.h, ty.as_mut_ptr()) }) .and( Type::from_mco(unsafe { ty.assume_init() }) .ok_or(Error::new_sql(mcosql_error_code::RUNTIME_ERROR)), ) } /// Returns the number of elements in the sequence. pub fn count(&self) -> Result<usize> { let mut ret = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_seq_count(self.val.h, ret.as_mut_ptr()) }) .and(Ok(unsafe { ret.assume_init() } as usize)) } /// Returns an iterator for the sequence. pub fn iterator(&'a self) -> Result<SequenceIterator<'a>> { self.get_iterator() .and(self.reset()) .and(Ok(SequenceIterator::new(self))) } fn get_iterator(&self) -> Result<()> { result_from_code(unsafe { exdb_sys::mcosql_rs_seq_get_iterator(self.val.h) }) } fn reset(&self) -> Result<()> { result_from_code(unsafe { exdb_sys::mcosql_rs_seq_reset(self.val.h) }) } unsafe fn next(&self) -> Result<exdb_sys::mcosql_rs_value> { let mut ret = MaybeUninit::uninit(); result_from_code(exdb_sys::mcosql_rs_seq_next(self.val.h, ret.as_mut_ptr())) .and(Ok(ret.assume_init())) } fn allocator(&'a self) -> Result<AllocatorRef<'a>> { let mut alloc = MaybeUninit::uninit(); result_from_code(unsafe { exdb_sys::mcosql_rs_seq_allocator(self.val.h, alloc.as_mut_ptr()) }) .and(Ok(AllocatorRef::from_handle( unsafe { alloc.assume_init() }, self, ))) } } /// A sequence iterator. /// /// This type is used to iterate through the items of the sequence. Like the /// `Cursor` type, it does not follow the conventions of the standard Rust /// iterators, because lifetimes of the values it returns are constrained /// by the lifetime of the sequence. /// /// The iterator is initially positioned before the first item. pub struct SequenceIterator<'a> { seq: &'a Sequence<'a>, val_ref: Ref<'a>, } impl<'a> SequenceIterator<'a> { fn new(seq: &'a Sequence<'a>) -> Self { let alloc = seq.allocator().unwrap(); let r = exdb_sys::mcosql_rs_value_ref { allocator: alloc.h, ref_: ptr::null_mut(), }; SequenceIterator { seq, val_ref: Ref::from_handle(r, seq), } } /// Advances the iterator. /// /// If this function returns `true`, the current element can be accessed. /// `false` indicates that the iterator has been moved past the last /// element. pub fn advance(&mut self) -> Result<bool> { unsafe { self.val_ref.replace_value(self.seq.next()?) }; if self.val_ref.is_null_ref() { Ok(false) } else { Ok(true) } } /// Returns the element currently pointed at by the iterator. /// /// Returns `None` if the iterator hasn't been advanced at least once, /// or has reached the end of the sequence. pub fn current_value(&'a self) -> Option<Ref<'a>> { if self.val_ref.is_null_ref() { None } else { // Produce a defused reference Some(self.val_ref.defused_clone()) } } } /// A fixed-width integer. /// /// This type is used to pass fixed-width integers between the application code /// and the SQL engine. pub struct Numeric { val_scaled: i64, prec: usize, } impl Numeric { /// Constructs a new fixed-width integer from a scaled value and precision. /// /// Returns `None` if precision is greater or equal to 19. /// /// # Examples /// /// A numeric value of `12.345` can be constructed using a scaled value of /// `12345` and a precision of `3`: /// /// ``` /// # use extremedb::sql::value::Numeric; /// let num = Numeric::new(12345, 3).unwrap(); /// assert_eq!(num.int_part(), 12); /// assert_eq!(num.fract_part(), 345); /// ``` pub fn new(val_scaled: i64, prec: usize) -> Option<Self> { if prec <= 19 { Some(Numeric { val_scaled, prec }) } else { None } } /// Returns the scaled value. pub fn value_scaled(&self) -> i64 { self.val_scaled } /// Returns the precision. pub fn precision(&self) -> usize { self.prec } /// Returns the integer part of the numeric value. pub fn int_part(&self) -> i64 { self.val_scaled / self.scale() as i64 } /// Returns the fractional part of the numeric value. pub fn fract_part(&self) -> u64 { (self.val_scaled.abs() as u64).wrapping_rem(self.scale() as u64) } /// Destructures the numeric value into the scaled value and the precision. pub fn destruct(self) -> (i64, usize) { (self.val_scaled, self.prec) } fn scale(&self) -> usize { 10usize.pow(self.prec as u32) } } impl Into<f64> for Numeric { fn into(self) -> f64 { self.val_scaled as f64 / self.scale() as f64 } } impl Display for Numeric { fn fmt(&self, f: &mut Formatter<'_>) -> std::result::Result<(), FmtError> { write!(f, "{}.{}", self.int_part(), self.fract_part()) } } impl ToValue for Numeric { fn to_value<'a>(&self, alloc: AllocatorRef<'a>) -> Result<Value<'a>> { Value::new_numeric(self.val_scaled, self.prec, alloc) } } /// An SQL blob. /// /// An *e*X*treme*DB SQL blob is a large binary object that can contain /// arbitrary data. /// /// This type contains public methods that allow the applications to read the /// data. A blob keeps an internal read pointer; each read operation advances /// it by the number of bytes read. To revert the pointer to the beginning of /// the blob's data, use the [`reset()`] method. /// /// A [`Value`] can only be converted into a `Blob` if it has the `Blob` /// type. The opposite conversion is always possible. /// /// [`Value`]: ./struct.Value.html /// [`reset()`]: #method.reset // WARNING: must have same repr as Value! Value is cast to Blob in Value::as_blob #[repr(transparent)] pub struct Blob<'a> { val: Value<'a>, } impl<'a> Blob<'a> { /// Returns the number of bytes available to be extracted with a single /// `get()` operation. /// /// This is *not* the total size of the blob. If the blob is split into /// segments, this can be equal to the size of one segment. pub fn available(&self) -> Result<usize> { let mut avail: exdb_sys::size_t = 0; result_from_code(unsafe { exdb_sys::mcosql_rs_blob_available(self.val.h, &mut avail) }) .and(Ok(avail as usize)) } /// Reads the blob data into the buffer. /// /// This method will fill the buffer up to its capacity. If the number /// of bytes available for reading is smaller than the buffer's capacity, /// this method will perform multiple reads. pub fn get_into(&self, buf: &mut Vec<u8>) -> Result<()> { unsafe { let new_len = self.get_raw(buf.as_mut_ptr() as *mut c_void, buf.capacity())?; buf.set_len(new_len) }; Ok(()) } /// Reads the given number of bytes from the blob. /// /// If the number of bytes available for reading is smaller than the /// requested size, this method will perform multiple reads. pub fn get(&self, size: usize) -> Result<Vec<u8>> { let mut ret = Vec::with_capacity(size); self.get_into(&mut ret).and(Ok(ret)) } /// Resets the blob's read pointer. pub fn reset(&self) -> Result<()> { result_from_code(unsafe { exdb_sys::mcosql_rs_blob_reset(self.val.h, 0) }) } unsafe fn get_raw(&self, p: *mut c_void, l: usize) -> Result<usize> { let mut total: exdb_sys::size_t = 0; let lsz = l as exdb_sys::size_t; while total < lsz { let mut nread: exdb_sys::size_t = 0; result_from_code(exdb_sys::mcosql_rs_blob_get( self.val.h, p.add(total as usize), lsz - total, &mut nread, ))?; if nread == 0 { break; } else { total += nread; } } Ok(total as usize) } } /// A `Binary` value wrapper. /// /// The sole purpose of this type is passing `Binary` values to the SQL engine. /// /// *Note that slices of `u8` are converted to [`Array`] when passed as /// statement parameters.* /// /// [`Array`]: ./struct.Array.html pub struct Binary<'a>(&'a [u8]); impl<'a> Binary<'a> { /// Creates a new `Binary` value wrapper. pub fn new(bytes: &'a [u8]) -> Self { Binary(bytes) } } impl ToValue for bool { fn to_value<'a>(&self, _alloc: AllocatorRef<'a>) -> Result<Value<'a>> { Value::new_bool(*self) } } impl ToValue for u8 { fn to_value<'a>(&self, alloc: AllocatorRef<'a>) -> Result<Value<'a>> { Value::new_int(*self as i64, alloc) } } impl ToValue for u16 { fn to_value<'a>(&self, alloc: AllocatorRef<'a>) -> Result<Value<'a>> { Value::new_int(*self as i64, alloc) } } impl ToValue for u32 { fn to_value<'a>(&self, alloc: AllocatorRef<'a>) -> Result<Value<'a>> { Value::new_int(*self as i64, alloc) } } impl ToValue for u64 { fn to_value<'a>(&self, alloc: AllocatorRef<'a>) -> Result<Value<'a>> { Value::new_int(*self as i64, alloc) } } impl ToValue for i8 { fn to_value<'a>(&self, alloc: AllocatorRef<'a>) -> Result<Value<'a>> { Value::new_int(*self as i64, alloc) } } impl ToValue for i16 { fn to_value<'a>(&self, alloc: AllocatorRef<'a>) -> Result<Value<'a>> { Value::new_int(*self as i64, alloc) } } impl ToValue for i32 { fn to_value<'a>(&self, alloc: AllocatorRef<'a>) -> Result<Value<'a>> { Value::new_int(*self as i64, alloc) } } impl ToValue for i64 { fn to_value<'a>(&self, alloc: AllocatorRef<'a>) -> Result<Value<'a>> { Value::new_int(*self as i64, alloc) } } impl ToValue for f32 { fn to_value<'a>(&self, alloc: AllocatorRef<'a>) -> Result<Value<'a>> { Value::new_real(*self as f64, alloc) } } impl ToValue for f64 { fn to_value<'a>(&self, alloc: AllocatorRef<'a>) -> Result<Value<'a>> { Value::new_real(*self as f64, alloc) } } impl ToValue for &str { fn to_value<'a>(&self, alloc: AllocatorRef<'a>) -> Result<Value<'a>> { Value::new_string(self, alloc) } } impl ToValue for Binary<'_> { fn to_value<'a>(&self, alloc: AllocatorRef<'a>) -> Result<Value<'a>> { Value::new_binary(self.0, alloc) } } impl<T: ArrayElem> ToValue for &[T] { fn to_value<'a>(&self, alloc: AllocatorRef<'a>) -> Result<Value<'a>> { let array = Array::new(self, alloc)?; Ok(array.into()) } } impl<T: ToValue> ToValue for Option<T> { fn to_value<'a>(&self, alloc: AllocatorRef<'a>) -> Result<Value<'a>> { match self { Some(val) => val.to_value(alloc), None => Value::new_null(), } } } impl ToValue for SystemTime { fn to_value<'a>(&self, alloc: AllocatorRef<'a>) -> Result<Value<'a>> { Value::new_date_time(self, alloc) } } /// A trait for retrieving the SQL type of the implementing Rust type. pub trait StaticTypeInfo { fn static_type() -> Type; } macro_rules! impl_static_type_info { ($ty:ty, $col_ty:path) => { impl StaticTypeInfo for $ty { fn static_type() -> Type { $col_ty } } }; } impl_static_type_info!(u8, Type::UInt1); impl_static_type_info!(u16, Type::UInt2); impl_static_type_info!(u32, Type::UInt4); impl_static_type_info!(u64, Type::UInt8); impl_static_type_info!(i8, Type::Int1); impl_static_type_info!(i16, Type::Int2); impl_static_type_info!(i32, Type::Int4); impl_static_type_info!(i64, Type::Int8); impl_static_type_info!(f32, Type::Real4); impl_static_type_info!(f64, Type::Real8); impl_static_type_info!(&str, Type::String); impl_static_type_info!(SystemTime, Type::Time); /// A marker trait for types that can be an element of an SQL array. pub trait ArrayElem: ToValue + StaticTypeInfo {} impl<T: ToValue + StaticTypeInfo> ArrayElem for T {}