ISAR/rusqlite
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Merge pull request #122 from gwenn/zeroblob

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Introduce ZeroBlob struct.
This commit is contained in:
John Gallagher 2016-02-01 14:14:14 -05:00
commit 55dde134e1
1 changed files with 17 additions and 1 deletions
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18
src/blob.rs
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@ -17,6 +17,7 @@
//! extern crate rusqlite; //! extern crate rusqlite;
//! //!
//! use rusqlite::{Connection, DatabaseName}; //! use rusqlite::{Connection, DatabaseName};
//! use rusqlite::blob::ZeroBlob;
//! use std::io::{Read, Write, Seek, SeekFrom}; //! use std::io::{Read, Write, Seek, SeekFrom};
//! //!
//! fn main() { //! fn main() {
@ -38,7 +39,7 @@
//! let bytes_read = blob.read(&mut buf[..]).unwrap(); //! let bytes_read = blob.read(&mut buf[..]).unwrap();
//! assert_eq!(bytes_read, 10); // note we read 10 bytes because the blob has size 10 //! assert_eq!(bytes_read, 10); // note we read 10 bytes because the blob has size 10
//! //!
//! db.execute("INSERT INTO test (content) VALUES (ZEROBLOB(64))", &[]).unwrap(); //! db.execute("INSERT INTO test (content) VALUES (?)", &[&ZeroBlob(64)]).unwrap();
//! //!
//! // given a new row ID, we can reopen the blob on that row //! // given a new row ID, we can reopen the blob on that row
//! let rowid = db.last_insert_rowid(); //! let rowid = db.last_insert_rowid();
@ -51,8 +52,10 @@ use std::io;
use std::cmp::min; use std::cmp::min;
use std::mem; use std::mem;
use std::ptr; use std::ptr;
use libc::c_int;
use super::ffi; use super::ffi;
use super::types::ToSql;
use {Result, Connection, DatabaseName}; use {Result, Connection, DatabaseName};
/// Handle to an open BLOB. /// Handle to an open BLOB.
@ -232,6 +235,19 @@ impl<'conn> Drop for Blob<'conn> {
} }
} }
/// BLOB of length N that is filled with zeroes.
/// Zeroblobs are intended to serve as placeholders for BLOBs whose content is later written using incremental BLOB I/O routines.
/// A negative value for the zeroblob results in a zero-length BLOB.
#[derive(Copy,Clone)]
pub struct ZeroBlob(pub i32);
impl ToSql for ZeroBlob {
unsafe fn bind_parameter(&self, stmt: *mut ffi::sqlite3_stmt, col: c_int) -> c_int {
let ZeroBlob(length) = *self;
ffi::sqlite3_bind_zeroblob(stmt, col, length)
}
}
#[cfg(test)] #[cfg(test)]
mod test { mod test {
use std::io::{BufReader, BufRead, BufWriter, Read, Write, Seek, SeekFrom}; use std::io::{BufReader, BufRead, BufWriter, Read, Write, Seek, SeekFrom};