Merge pull request #1008 from JaydenElliott/feature/rename_all_attr

added `rename_all` container attribute for enums and structs

postgres-derive-test/src/composites.rs

@@ -89,6 +89,49 @@ fn name_overrides() {
     );
 }
 
+#[test]
+fn rename_all_overrides() {
+    #[derive(FromSql, ToSql, Debug, PartialEq)]
+    #[postgres(name = "inventory_item", rename_all = "SCREAMING_SNAKE_CASE")]
+    struct InventoryItem {
+        name: String,
+        supplier_id: i32,
+        #[postgres(name = "Price")]
+        price: Option<f64>,
+    }
+
+    let mut conn = Client::connect("user=postgres host=localhost port=5433", NoTls).unwrap();
+    conn.batch_execute(
+        "CREATE TYPE pg_temp.inventory_item AS (
+            \"NAME\" TEXT,
+            \"SUPPLIER_ID\" INT,
+            \"Price\" DOUBLE PRECISION
+        );",
+    )
+    .unwrap();
+
+    let item = InventoryItem {
+        name: "foobar".to_owned(),
+        supplier_id: 100,
+        price: Some(15.50),
+    };
+
+    let item_null = InventoryItem {
+        name: "foobar".to_owned(),
+        supplier_id: 100,
+        price: None,
+    };
+
+    test_type(
+        &mut conn,
+        "inventory_item",
+        &[
+            (item, "ROW('foobar', 100, 15.50)"),
+            (item_null, "ROW('foobar', 100, NULL)"),
+        ],
+    );
+}
+
 #[test]
 fn wrong_name() {
     #[derive(FromSql, ToSql, Debug, PartialEq)]

postgres-derive-test/src/enums.rs

@@ -53,6 +53,35 @@ fn name_overrides() {
     );
 }
 
+#[test]
+fn rename_all_overrides() {
+    #[derive(Debug, ToSql, FromSql, PartialEq)]
+    #[postgres(name = "mood", rename_all = "snake_case")]
+    enum Mood {
+        VerySad,
+        #[postgres(name = "okay")]
+        Ok,
+        VeryHappy,
+    }
+
+    let mut conn = Client::connect("user=postgres host=localhost port=5433", NoTls).unwrap();
+    conn.execute(
+        "CREATE TYPE pg_temp.mood AS ENUM ('very_sad', 'okay', 'very_happy')",
+        &[],
+    )
+    .unwrap();
+
+    test_type(
+        &mut conn,
+        "mood",
+        &[
+            (Mood::VerySad, "'very_sad'"),
+            (Mood::Ok, "'okay'"),
+            (Mood::VeryHappy, "'very_happy'"),
+        ],
+    );
+}
+
 #[test]
 fn wrong_name() {
     #[derive(Debug, ToSql, FromSql, PartialEq)]

postgres-derive/Cargo.toml

@@ -15,3 +15,4 @@ test = false
 syn = "2.0"
 proc-macro2 = "1.0"
 quote = "1.0"
+heck = "0.4"

postgres-derive/src/case.rs

@@ -0,0 +1,110 @@
+#[allow(deprecated, unused_imports)]
+use std::ascii::AsciiExt;
+
+use heck::{
+    ToKebabCase, ToLowerCamelCase, ToShoutyKebabCase, ToShoutySnakeCase, ToSnakeCase, ToTrainCase,
+    ToUpperCamelCase,
+};
+
+use self::RenameRule::*;
+
+/// The different possible ways to change case of fields in a struct, or variants in an enum.
+#[allow(clippy::enum_variant_names)]
+#[derive(Copy, Clone, PartialEq)]
+pub enum RenameRule {
+    /// Rename direct children to "lowercase" style.
+    LowerCase,
+    /// Rename direct children to "UPPERCASE" style.
+    UpperCase,
+    /// Rename direct children to "PascalCase" style, as typically used for
+    /// enum variants.
+    PascalCase,
+    /// Rename direct children to "camelCase" style.
+    CamelCase,
+    /// Rename direct children to "snake_case" style, as commonly used for
+    /// fields.
+    SnakeCase,
+    /// Rename direct children to "SCREAMING_SNAKE_CASE" style, as commonly
+    /// used for constants.
+    ScreamingSnakeCase,
+    /// Rename direct children to "kebab-case" style.
+    KebabCase,
+    /// Rename direct children to "SCREAMING-KEBAB-CASE" style.
+    ScreamingKebabCase,
+
+    /// Rename direct children to "Train-Case" style.
+    TrainCase,
+}
+
+pub const RENAME_RULES: &[&str] = &[
+    "lowercase",
+    "UPPERCASE",
+    "PascalCase",
+    "camelCase",
+    "snake_case",
+    "SCREAMING_SNAKE_CASE",
+    "kebab-case",
+    "SCREAMING-KEBAB-CASE",
+    "Train-Case",
+];
+
+impl RenameRule {
+    pub fn from_str(rule: &str) -> Option<RenameRule> {
+        match rule {
+            "lowercase" => Some(LowerCase),
+            "UPPERCASE" => Some(UpperCase),
+            "PascalCase" => Some(PascalCase),
+            "camelCase" => Some(CamelCase),
+            "snake_case" => Some(SnakeCase),
+            "SCREAMING_SNAKE_CASE" => Some(ScreamingSnakeCase),
+            "kebab-case" => Some(KebabCase),
+            "SCREAMING-KEBAB-CASE" => Some(ScreamingKebabCase),
+            "Train-Case" => Some(TrainCase),
+            _ => None,
+        }
+    }
+    /// Apply a renaming rule to an enum or struct field, returning the version expected in the source.
+    pub fn apply_to_field(&self, variant: &str) -> String {
+        match *self {
+            LowerCase => variant.to_lowercase(),
+            UpperCase => variant.to_uppercase(),
+            PascalCase => variant.to_upper_camel_case(),
+            CamelCase => variant.to_lower_camel_case(),
+            SnakeCase => variant.to_snake_case(),
+            ScreamingSnakeCase => variant.to_shouty_snake_case(),
+            KebabCase => variant.to_kebab_case(),
+            ScreamingKebabCase => variant.to_shouty_kebab_case(),
+            TrainCase => variant.to_train_case(),
+        }
+    }
+}
+
+#[test]
+fn rename_field() {
+    for &(original, lower, upper, camel, snake, screaming, kebab, screaming_kebab) in &[
+        (
+            "Outcome", "outcome", "OUTCOME", "outcome", "outcome", "OUTCOME", "outcome", "OUTCOME",
+        ),
+        (
+            "VeryTasty",
+            "verytasty",
+            "VERYTASTY",
+            "veryTasty",
+            "very_tasty",
+            "VERY_TASTY",
+            "very-tasty",
+            "VERY-TASTY",
+        ),
+        ("A", "a", "A", "a", "a", "A", "a", "A"),
+        ("Z42", "z42", "Z42", "z42", "z42", "Z42", "z42", "Z42"),
+    ] {
+        assert_eq!(LowerCase.apply_to_field(original), lower);
+        assert_eq!(UpperCase.apply_to_field(original), upper);
+        assert_eq!(PascalCase.apply_to_field(original), original);
+        assert_eq!(CamelCase.apply_to_field(original), camel);
+        assert_eq!(SnakeCase.apply_to_field(original), snake);
+        assert_eq!(ScreamingSnakeCase.apply_to_field(original), screaming);
+        assert_eq!(KebabCase.apply_to_field(original), kebab);
+        assert_eq!(ScreamingKebabCase.apply_to_field(original), screaming_kebab);
+    }
+}

postgres-derive/src/composites.rs

@@ -4,7 +4,7 @@ use syn::{
     TypeParamBound,
 };
 
-use crate::overrides::Overrides;
+use crate::{case::RenameRule, overrides::Overrides};
 
 pub struct Field {
     pub name: String,
@@ -13,18 +13,26 @@ pub struct Field {
 }
 
 impl Field {
-    pub fn parse(raw: &syn::Field) -> Result<Field, Error> {
+    pub fn parse(raw: &syn::Field, rename_all: Option<RenameRule>) -> Result<Field, Error> {
-        let overrides = Overrides::extract(&raw.attrs)?;
+        let overrides = Overrides::extract(&raw.attrs, false)?;
-
         let ident = raw.ident.as_ref().unwrap().clone();
-        Ok(Field {
+
-            name: overrides.name.unwrap_or_else(|| {
+        // field level name override takes precendence over container level rename_all override
+        let name = match overrides.name {
+            Some(n) => n,
+            None => {
                 let name = ident.to_string();
-                match name.strip_prefix("r#") {
+                let stripped = name.strip_prefix("r#").map(String::from).unwrap_or(name);
-                    Some(name) => name.to_string(),
+
-                    None => name,
+                match rename_all {
+                    Some(rule) => rule.apply_to_field(&stripped),
+                    None => stripped,
                 }
-            }),
+            }
+        };
+
+        Ok(Field {
+            name,
             ident,
             type_: raw.ty.clone(),
         })

postgres-derive/src/enums.rs

@@ -1,6 +1,6 @@
 use syn::{Error, Fields, Ident};
 
-use crate::overrides::Overrides;
+use crate::{case::RenameRule, overrides::Overrides};
 
 pub struct Variant {
     pub ident: Ident,
@@ -8,7 +8,7 @@ pub struct Variant {
 }
 
 impl Variant {
-    pub fn parse(raw: &syn::Variant) -> Result<Variant, Error> {
+    pub fn parse(raw: &syn::Variant, rename_all: Option<RenameRule>) -> Result<Variant, Error> {
         match raw.fields {
             Fields::Unit => {}
             _ => {
@@ -18,11 +18,16 @@ impl Variant {
                 ))
             }
         }
+        let overrides = Overrides::extract(&raw.attrs, false)?;
 
-        let overrides = Overrides::extract(&raw.attrs)?;
+        // variant level name override takes precendence over container level rename_all override
+        let name = overrides.name.unwrap_or_else(|| match rename_all {
+            Some(rule) => rule.apply_to_field(&raw.ident.to_string()),
+            None => raw.ident.to_string(),
+        });
         Ok(Variant {
             ident: raw.ident.clone(),
-            name: overrides.name.unwrap_or_else(|| raw.ident.to_string()),
+            name,
         })
     }
 }

postgres-derive/src/fromsql.rs

@@ -15,16 +15,19 @@ use crate::enums::Variant;
 use crate::overrides::Overrides;
 
 pub fn expand_derive_fromsql(input: DeriveInput) -> Result<TokenStream, Error> {
-    let overrides = Overrides::extract(&input.attrs)?;
+    let overrides = Overrides::extract(&input.attrs, true)?;
 
-    if overrides.name.is_some() && overrides.transparent {
+    if (overrides.name.is_some() || overrides.rename_all.is_some()) && overrides.transparent {
         return Err(Error::new_spanned(
             &input,
-            "#[postgres(transparent)] is not allowed with #[postgres(name = \"...\")]",
+            "#[postgres(transparent)] is not allowed with #[postgres(name = \"...\")] or #[postgres(rename_all = \"...\")]",
         ));
     }
 
-    let name = overrides.name.unwrap_or_else(|| input.ident.to_string());
+    let name = overrides
+        .name
+        .clone()
+        .unwrap_or_else(|| input.ident.to_string());
 
     let (accepts_body, to_sql_body) = if overrides.transparent {
         match input.data {
@@ -51,7 +54,7 @@ pub fn expand_derive_fromsql(input: DeriveInput) -> Result<TokenStream, Error> {
             let variants = data
                 .variants
                 .iter()
-                .map(Variant::parse)
+                .map(|variant| Variant::parse(variant, overrides.rename_all))
                 .collect::<Result<Vec<_>, _>>()?;
             (
                 accepts::enum_body(&name, &variants),
@@ -75,7 +78,7 @@ pub fn expand_derive_fromsql(input: DeriveInput) -> Result<TokenStream, Error> {
             let fields = fields
                 .named
                 .iter()
-                .map(Field::parse)
+                .map(|field| Field::parse(field, overrides.rename_all))
                 .collect::<Result<Vec<_>, _>>()?;
             (
                 accepts::composite_body(&name, "FromSql", &fields),

postgres-derive/src/lib.rs

@@ -7,6 +7,7 @@ use proc_macro::TokenStream;
 use syn::parse_macro_input;
 
 mod accepts;
+mod case;
 mod composites;
 mod enums;
 mod fromsql;

postgres-derive/src/overrides.rs

@@ -1,15 +1,19 @@
 use syn::punctuated::Punctuated;
 use syn::{Attribute, Error, Expr, ExprLit, Lit, Meta, Token};
 
+use crate::case::{RenameRule, RENAME_RULES};
+
 pub struct Overrides {
     pub name: Option<String>,
+    pub rename_all: Option<RenameRule>,
     pub transparent: bool,
 }
 
 impl Overrides {
-    pub fn extract(attrs: &[Attribute]) -> Result<Overrides, Error> {
+    pub fn extract(attrs: &[Attribute], container_attr: bool) -> Result<Overrides, Error> {
         let mut overrides = Overrides {
             name: None,
+            rename_all: None,
             transparent: false,
         };
 
@@ -28,7 +32,15 @@ impl Overrides {
             for item in nested {
                 match item {
                     Meta::NameValue(meta) => {
-                        if !meta.path.is_ident("name") {
+                        let name_override = meta.path.is_ident("name");
+                        let rename_all_override = meta.path.is_ident("rename_all");
+                        if !container_attr && rename_all_override {
+                            return Err(Error::new_spanned(
+                                &meta.path,
+                                "rename_all is a container attribute",
+                            ));
+                        }
+                        if !name_override && !rename_all_override {
                             return Err(Error::new_spanned(&meta.path, "unknown override"));
                         }
 
@@ -41,7 +53,25 @@ impl Overrides {
                             }
                         };
 
-                        overrides.name = Some(value);
+                        if name_override {
+                            overrides.name = Some(value);
+                        } else if rename_all_override {
+                            let rename_rule = RenameRule::from_str(&value).ok_or_else(|| {
+                                Error::new_spanned(
+                                    &meta.value,
+                                    format!(
+                                        "invalid rename_all rule, expected one of: {}",
+                                        RENAME_RULES
+                                            .iter()
+                                            .map(|rule| format!("\"{}\"", rule))
+                                            .collect::<Vec<_>>()
+                                            .join(", ")
+                                    ),
+                                )
+                            })?;
+
+                            overrides.rename_all = Some(rename_rule);
+                        }
                     }
                     Meta::Path(path) => {
                         if !path.is_ident("transparent") {

postgres-derive/src/tosql.rs

@@ -13,16 +13,19 @@ use crate::enums::Variant;
 use crate::overrides::Overrides;
 
 pub fn expand_derive_tosql(input: DeriveInput) -> Result<TokenStream, Error> {
-    let overrides = Overrides::extract(&input.attrs)?;
+    let overrides = Overrides::extract(&input.attrs, true)?;
 
-    if overrides.name.is_some() && overrides.transparent {
+    if (overrides.name.is_some() || overrides.rename_all.is_some()) && overrides.transparent {
         return Err(Error::new_spanned(
             &input,
-            "#[postgres(transparent)] is not allowed with #[postgres(name = \"...\")]",
+            "#[postgres(transparent)] is not allowed with #[postgres(name = \"...\")] or #[postgres(rename_all = \"...\")]",
         ));
     }
 
-    let name = overrides.name.unwrap_or_else(|| input.ident.to_string());
+    let name = overrides
+        .name
+        .clone()
+        .unwrap_or_else(|| input.ident.to_string());
 
     let (accepts_body, to_sql_body) = if overrides.transparent {
         match input.data {
@@ -47,7 +50,7 @@ pub fn expand_derive_tosql(input: DeriveInput) -> Result<TokenStream, Error> {
                 let variants = data
                     .variants
                     .iter()
-                    .map(Variant::parse)
+                    .map(|variant| Variant::parse(variant, overrides.rename_all))
                     .collect::<Result<Vec<_>, _>>()?;
                 (
                     accepts::enum_body(&name, &variants),
@@ -69,7 +72,7 @@ pub fn expand_derive_tosql(input: DeriveInput) -> Result<TokenStream, Error> {
                 let fields = fields
                     .named
                     .iter()
-                    .map(Field::parse)
+                    .map(|field| Field::parse(field, overrides.rename_all))
                     .collect::<Result<Vec<_>, _>>()?;
                 (
                     accepts::composite_body(&name, "ToSql", &fields),

postgres-types/src/lib.rs

@@ -125,6 +125,37 @@
 //!     Happy,
 //! }
 //! ```
+//!
+//! Alternatively, the `#[postgres(rename_all = "...")]` attribute can be used to rename all fields or variants
+//! with the chosen casing convention. This will not affect the struct or enum's type name. Note that
+//! `#[postgres(name = "...")]` takes precendence when used in conjunction with `#[postgres(rename_all = "...")]`:
+//!
+//! ```rust
+//! # #[cfg(feature = "derive")]
+//! use postgres_types::{ToSql, FromSql};
+//!
+//! # #[cfg(feature = "derive")]
+//! #[derive(Debug, ToSql, FromSql)]
+//! #[postgres(name = "mood", rename_all = "snake_case")]
+//! enum Mood {
+//!     VerySad,        // very_sad
+//!     #[postgres(name = "ok")]
+//!     Ok,             // ok
+//!     VeryHappy,      // very_happy
+//! }
+//! ```
+//!
+//! The following case conventions are supported:
+//! - `"lowercase"`
+//! - `"UPPERCASE"`
+//! - `"PascalCase"`
+//! - `"camelCase"`
+//! - `"snake_case"`
+//! - `"SCREAMING_SNAKE_CASE"`
+//! - `"kebab-case"`
+//! - `"SCREAMING-KEBAB-CASE"`
+//! - `"Train-Case"`
+
 #![doc(html_root_url = "https://docs.rs/postgres-types/0.2")]
 #![warn(clippy::all, rust_2018_idioms, missing_docs)]