Merge remote-tracking branch 'jgallagher/master' into rustfmt

This commit is contained in:
gwenn 2016-02-02 19:15:35 +01:00
commit 24d5093ab8
3 changed files with 22 additions and 47 deletions

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@ -4,6 +4,10 @@
* Adds `types::Value` for dynamic column types.
* Adds support for user-defined aggregate functions (behind the existing `functions` Cargo feature).
* Introduces a `RowIndex` trait allowing columns to be fetched via index (as before) or name (new).
* Introduces `ZeroBlob` type under the `blob` module/feature exposing SQLite's zeroblob API.
* Adds CI testing for Windows via AppVeyor.
* Fixes a warning building libsqlite3-sys under Rust 1.6.
* Adds an unsafe `handle()` method to `Connection`. Please file an issue if you actually use it.
# Version 0.6.0 (2015-12-17)

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@ -1,6 +1,7 @@
# Rusqlite
[![Build Status](https://api.travis-ci.org/jgallagher/rusqlite.svg?branch=master)](https://travis-ci.org/jgallagher/rusqlite)
[![Travis Build Status](https://api.travis-ci.org/jgallagher/rusqlite.svg?branch=master)](https://travis-ci.org/jgallagher/rusqlite)
[![AppVeyor Build Status](https://ci.appveyor.com/api/projects/status/github/jgallagher/rusqlite?branch=master&svg=true)](https://ci.appveyor.com/project/jgallagher/rusqlite)
Rusqlite is an ergonomic wrapper for using SQLite from Rust. It attempts to expose
an interface similar to [rust-postgres](https://github.com/sfackler/rust-postgres). View the full
@ -72,45 +73,6 @@ features](http://doc.crates.io/manifest.html#the-features-section). They are:
* [`blob`](http://jgallagher.github.io/rusqlite/rusqlite/blob/index.html)
gives `std::io::{Read, Write, Seek}` access to SQL BLOBs.
### Design of Rows and Row
To retrieve the result rows from a query, SQLite requires you to call
[sqlite3_step()](https://www.sqlite.org/c3ref/step.html) on a prepared statement. You can only
retrieve the values of the "current" row. From the Rust point of view, this means that each row
is only valid until the next row is fetched. [rust-sqlite3](https://github.com/dckc/rust-sqlite3)
solves this the correct way with lifetimes. However, this means that the result rows do not
satisfy the [Iterator](http://doc.rust-lang.org/std/iter/trait.Iterator.html) trait, which means
you cannot (as easily) loop over the rows, or use many of the helpful Iterator methods like `map`
and `filter`.
Instead, Rusqlite's `Rows` handle does conform to `Iterator`. It ensures safety by
performing checks at runtime to ensure you do not try to retrieve the values of a "stale" row, and
will panic if you do so. A specific example that will panic:
```rust
fn bad_function_will_panic(conn: &Connection) -> Result<i64> {
let mut stmt = try!(conn.prepare("SELECT id FROM my_table"));
let mut rows = try!(stmt.query(&[]));
let row0 = try!(rows.next().unwrap());
// row 0 is valid now...
let row1 = try!(rows.next().unwrap());
// row 0 is now STALE, and row 1 is valid
let my_id = row0.get(0); // WILL PANIC because row 0 is stale
Ok(my_id)
}
```
There are other, less obvious things that may result in a panic as well, such as calling
`collect()` on a `Rows` and then trying to use the collected rows.
Strongly consider using the method `query_map()` instead, if you can.
`query_map()` returns an iterator over rows-mapped-to-some-type. This
iterator does not have any of the above issues with panics due to attempting to
access stale rows.
## Author
John Gallagher, johnkgallagher@gmail.com

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@ -496,6 +496,18 @@ impl Connection {
self.db.borrow_mut().load_extension(dylib_path.as_ref(), entry_point)
}
/// Get access to the underlying SQLite database connection handle.
///
/// # Warning
///
/// You should not need to use this function. If you do need to, please [open an issue
/// on the rusqlite repository](https://github.com/jgallagher/rusqlite/issues) and describe
/// your use case. This function is unsafe because it gives you raw access to the SQLite
/// connection, and what you do with it could impact the safety of this `Connection`.
pub unsafe fn handle(&self) -> *mut ffi::Struct_sqlite3 {
self.db.borrow().db()
}
fn decode_result(&self, code: c_int) -> Result<()> {
self.db.borrow_mut().decode_result(code)
}
@ -977,6 +989,9 @@ pub type SqliteRows<'stmt> = Rows<'stmt>;
///
/// ## Warning
///
/// Strongly consider using `query_map` or `query_and_then` instead of `query`; the former do not
/// suffer from the following problem.
///
/// Due to the way SQLite returns result rows of a query, it is not safe to attempt to get values
/// from a row after it has become stale (i.e., `next()` has been called again on the `Rows`
/// iterator). For example:
@ -988,7 +1003,7 @@ pub type SqliteRows<'stmt> = Rows<'stmt>;
/// let mut rows = try!(stmt.query(&[]));
///
/// let row0 = try!(rows.next().unwrap());
/// // row 0 is value now...
/// // row 0 is valid for now...
///
/// let row1 = try!(rows.next().unwrap());
/// // row 0 is now STALE, and row 1 is valid
@ -1002,12 +1017,6 @@ pub type SqliteRows<'stmt> = Rows<'stmt>;
/// (which would result in a collection of rows, only the last of which can safely be used) and
/// `min`/`max` (which could return a stale row unless the last row happened to be the min or max,
/// respectively).
///
/// This problem could be solved by changing the signature of `next` to tie the lifetime of the
/// returned row to the lifetime of (a mutable reference to) the result rows handle, but this would
/// no longer implement `Iterator`, and therefore you would lose access to the majority of
/// functions which are useful (such as support for `for ... in ...` looping, `map`, `filter`,
/// etc.).
pub struct Rows<'stmt> {
stmt: &'stmt Statement<'stmt>,
current_row: Rc<Cell<c_int>>,