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Copy pathdata.rs
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187 lines (164 loc) · 6.3 KB
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use sqlx_core::database::Database;
use sqlx_core::describe::Describe;
use sqlx_core::executor::Executor;
#[cfg_attr(feature = "offline", derive(serde::Deserialize, serde::Serialize))]
#[cfg_attr(
feature = "offline",
serde(bound(
serialize = "Describe<DB>: serde::Serialize",
deserialize = "Describe<DB>: serde::de::DeserializeOwned"
))
)]
#[derive(Debug)]
pub struct QueryData<DB: Database> {
#[allow(dead_code)]
pub(super) query: String,
pub(super) describe: Describe<DB>,
#[cfg(feature = "offline")]
pub(super) hash: String,
}
impl<DB: Database> QueryData<DB> {
pub async fn from_db(
conn: impl Executor<'_, Database = DB>,
query: &str,
) -> crate::Result<Self> {
Ok(QueryData {
query: query.into(),
describe: conn.describe(query).await?,
#[cfg(feature = "offline")]
hash: offline::hash_string(query),
})
}
}
#[cfg(feature = "offline")]
pub mod offline {
use super::QueryData;
use std::fs::File;
use std::fmt::{self, Formatter};
use crate::database::DatabaseExt;
use proc_macro2::Span;
use serde::de::{Deserializer, IgnoredAny, MapAccess, Visitor};
use sqlx_core::describe::Describe;
use std::path::Path;
#[derive(serde::Deserialize)]
pub struct DynQueryData {
#[serde(skip)]
pub db_name: String,
pub query: String,
pub describe: serde_json::Value,
#[serde(skip)]
pub hash: String,
}
impl DynQueryData {
/// Find and deserialize the data table for this query from a shared `sqlx-data.json`
/// file. The expected structure is a JSON map keyed by the SHA-256 hash of queries in hex.
pub fn from_data_file(path: impl AsRef<Path>, query: &str) -> crate::Result<Self> {
serde_json::Deserializer::from_reader(
File::open(path.as_ref()).map_err(|e| {
format!("failed to open path {}: {}", path.as_ref().display(), e)
})?,
)
.deserialize_map(DataFileVisitor {
query,
hash: hash_string(query),
})
.map_err(Into::into)
}
}
impl<DB: DatabaseExt> QueryData<DB>
where
Describe<DB>: serde::Serialize + serde::de::DeserializeOwned,
{
pub fn from_dyn_data(dyn_data: DynQueryData) -> crate::Result<Self> {
assert!(!dyn_data.db_name.is_empty());
assert!(!dyn_data.hash.is_empty());
if DB::NAME == dyn_data.db_name {
let describe: Describe<DB> = serde_json::from_value(dyn_data.describe)?;
Ok(QueryData {
query: dyn_data.query,
describe,
hash: dyn_data.hash,
})
} else {
Err(format!(
"expected query data for {}, got data for {}",
DB::NAME,
dyn_data.db_name
)
.into())
}
}
pub fn save_in(&self, dir: impl AsRef<Path>, input_span: Span) -> crate::Result<()> {
// we save under the hash of the span representation because that should be unique
// per invocation
let path = dir.as_ref().join(format!(
"query-{}.json",
hash_string(&format!("{:?}", input_span))
));
serde_json::to_writer_pretty(
File::create(&path)
.map_err(|e| format!("failed to open path {}: {}", path.display(), e))?,
self,
)
.map_err(Into::into)
}
}
pub fn hash_string(query: &str) -> String {
// picked `sha2` because it's already in the dependency tree for both MySQL and Postgres
use sha2::{Digest, Sha256};
hex::encode(Sha256::digest(query.as_bytes()))
}
// lazily deserializes only the `QueryData` for the query we're looking for
struct DataFileVisitor<'a> {
query: &'a str,
hash: String,
}
impl<'de> Visitor<'de> for DataFileVisitor<'_> {
type Value = DynQueryData;
fn expecting(&self, f: &mut Formatter) -> fmt::Result {
write!(f, "expected map key {:?} or \"db\"", self.hash)
}
fn visit_map<A>(self, mut map: A) -> Result<Self::Value, <A as MapAccess<'de>>::Error>
where
A: MapAccess<'de>,
{
let mut db_name: Option<String> = None;
let query_data = loop {
// unfortunately we can't avoid this copy because deserializing from `io::Read`
// doesn't support deserializing borrowed values
let key = map.next_key::<String>()?.ok_or_else(|| {
serde::de::Error::custom(format_args!(
"failed to find data for query {}",
self.hash
))
})?;
// lazily deserialize the query data only
if key == "db" {
db_name = Some(map.next_value::<String>()?);
} else if key == self.hash {
let db_name = db_name.ok_or_else(|| {
serde::de::Error::custom("expected \"db\" key before query hash keys")
})?;
let mut query_data: DynQueryData = map.next_value()?;
if query_data.query == self.query {
query_data.db_name = db_name;
query_data.hash = self.hash.clone();
break query_data;
} else {
return Err(serde::de::Error::custom(format_args!(
"hash collision for stored queries:\n{:?}\n{:?}",
self.query, query_data.query
)));
};
} else {
// we don't care about entries that don't match our hash
let _ = map.next_value::<IgnoredAny>()?;
}
};
// Serde expects us to consume the whole map; fortunately they've got a convenient
// type to let us do just that
while let Some(_) = map.next_entry::<IgnoredAny, IgnoredAny>()? {}
Ok(query_data)
}
}
}