use proc_macro2::Span;
use std::slice::from_ref;
use syn::punctuated::Punctuated;
use syn::token::Comma;
use syn::Result;
use syn::{
Data, DataStruct, DeriveInput, Field as SynField, Fields, FieldsNamed, FieldsUnnamed, Ident,
LitBool, Path, Type,
};
use crate::attrs::{parse_attributes, StructAttr};
use crate::field::Field;
use crate::parsers::{BelongsTo, MysqlType, PostgresType, SqliteType};
use crate::util::camel_to_snake;
pub struct Model {
name: Path,
table_names: Vec<Path>,
pub primary_key_names: Vec<Ident>,
treat_none_as_default_value: Option<LitBool>,
treat_none_as_null: Option<LitBool>,
pub belongs_to: Vec<BelongsTo>,
pub sql_types: Vec<Type>,
pub aggregate: bool,
pub not_sized: bool,
pub foreign_derive: bool,
pub mysql_type: Option<MysqlType>,
pub sqlite_type: Option<SqliteType>,
pub postgres_type: Option<PostgresType>,
pub check_for_backend: Option<CheckForBackend>,
pub base_query: Option<syn::Expr>,
pub base_query_type: Option<syn::Type>,
fields: Vec<Field>,
}
pub enum CheckForBackend {
Backends(syn::punctuated::Punctuated<syn::TypePath, syn::Token![,]>),
Disabled(LitBool),
}
impl Model {
pub fn from_item(
item: &DeriveInput,
allow_unit_structs: bool,
allow_multiple_table: bool,
) -> Result<Self> {
let DeriveInput {
data, ident, attrs, ..
} = item;
let fields = match *data {
Data::Struct(DataStruct {
fields: Fields::Named(FieldsNamed { ref named, .. }),
..
}) => Some(named),
Data::Struct(DataStruct {
fields: Fields::Unnamed(FieldsUnnamed { ref unnamed, .. }),
..
}) => Some(unnamed),
_ if !allow_unit_structs => {
return Err(syn::Error::new(
proc_macro2::Span::mixed_site(),
"this derive can only be used on non-unit structs",
));
}
_ => None,
};
let mut table_names = vec![];
let mut primary_key_names = vec![Ident::new("id", Span::mixed_site())];
let mut treat_none_as_default_value = None;
let mut treat_none_as_null = None;
let mut belongs_to = vec![];
let mut sql_types = vec![];
let mut aggregate = false;
let mut not_sized = false;
let mut foreign_derive = false;
let mut mysql_type = None;
let mut sqlite_type = None;
let mut postgres_type = None;
let mut check_for_backend = None;
let mut base_query = None;
let mut base_query_type = None;
for attr in parse_attributes(attrs)? {
match attr.item {
StructAttr::SqlType(_, value) => sql_types.push(Type::Path(value)),
StructAttr::TableName(ident, value) => {
if !allow_multiple_table && !table_names.is_empty() {
return Err(syn::Error::new(
ident.span(),
"expected a single table name attribute\n\
note: remove this attribute",
));
}
table_names.push(value)
}
StructAttr::PrimaryKey(_, keys) => {
primary_key_names = keys.into_iter().collect();
}
StructAttr::TreatNoneAsDefaultValue(_, val) => {
treat_none_as_default_value = Some(val)
}
StructAttr::TreatNoneAsNull(_, val) => treat_none_as_null = Some(val),
StructAttr::BelongsTo(_, val) => belongs_to.push(val),
StructAttr::Aggregate(_) => aggregate = true,
StructAttr::NotSized(_) => not_sized = true,
StructAttr::ForeignDerive(_) => foreign_derive = true,
StructAttr::MysqlType(_, val) => mysql_type = Some(val),
StructAttr::SqliteType(_, val) => sqlite_type = Some(val),
StructAttr::PostgresType(_, val) => postgres_type = Some(val),
StructAttr::CheckForBackend(_, b) => {
check_for_backend = Some(b);
}
StructAttr::BaseQuery(_, e) => base_query = Some(e),
StructAttr::BaseQueryType(_, t) => base_query_type = Some(t),
}
}
let name = Ident::new(&infer_table_name(&ident.to_string()), ident.span()).into();
Ok(Self {
name,
table_names,
primary_key_names,
treat_none_as_default_value,
treat_none_as_null,
belongs_to,
sql_types,
aggregate,
not_sized,
foreign_derive,
mysql_type,
sqlite_type,
postgres_type,
fields: fields_from_item_data(fields)?,
check_for_backend,
base_query,
base_query_type,
})
}
pub fn table_names(&self) -> &[Path] {
match self.table_names.len() {
0 => from_ref(&self.name),
_ => &self.table_names,
}
}
pub fn fields(&self) -> &[Field] {
&self.fields
}
pub fn find_column(&self, column_name: &Ident) -> Result<&Field> {
self.fields()
.iter()
.find(|f| {
f.column_name()
.map(|c| c == *column_name)
.unwrap_or_default()
})
.ok_or_else(|| {
syn::Error::new(
column_name.span(),
format!("no field with column name `{column_name}`"),
)
})
}
pub fn treat_none_as_default_value(&self) -> bool {
self.treat_none_as_default_value
.as_ref()
.map(|v| v.value())
.unwrap_or(true)
}
pub fn treat_none_as_null(&self) -> bool {
self.treat_none_as_null
.as_ref()
.map(|v| v.value())
.unwrap_or(false)
}
}
fn fields_from_item_data(fields: Option<&Punctuated<SynField, Comma>>) -> Result<Vec<Field>> {
fields
.map(|fields| {
fields
.iter()
.enumerate()
.map(|(i, f)| Field::from_struct_field(f, i))
.collect::<Result<Vec<_>>>()
})
.unwrap_or_else(|| Ok(Vec::new()))
}
pub fn infer_table_name(name: &str) -> String {
let mut result = camel_to_snake(name);
result.push('s');
result
}
#[test]
fn infer_table_name_pluralizes_and_downcases() {
assert_eq!("foos", &infer_table_name("Foo"));
assert_eq!("bars", &infer_table_name("Bar"));
}
#[test]
fn infer_table_name_properly_handles_underscores() {
assert_eq!("foo_bars", &infer_table_name("FooBar"));
assert_eq!("foo_bar_bazs", &infer_table_name("FooBarBaz"));
}