use std::fmt::Write;
use scythe_backend::manifest::BackendManifest;
use scythe_backend::naming::{
enum_type_name, enum_variant_name, fn_name, row_struct_name, to_pascal_case,
};
use scythe_backend::types::resolve_type;
use scythe_core::analyzer::{AnalyzedQuery, CompositeInfo, EnumInfo};
use scythe_core::errors::{ErrorCode, ScytheError};
use scythe_core::parser::QueryCommand;
use crate::backend_trait::{CodegenBackend, ResolvedColumn, ResolvedParam};
const DEFAULT_MANIFEST_TOML: &str = include_str!("../../manifests/go-godror.toml");
pub struct GoGodrorBackend {
manifest: BackendManifest,
}
impl GoGodrorBackend {
pub fn new(engine: &str) -> Result<Self, ScytheError> {
match engine {
"oracle" => {}
_ => {
return Err(ScytheError::new(
ErrorCode::InternalError,
format!("go-godror only supports Oracle, got engine '{}'", engine),
));
}
}
let manifest = super::load_or_default_manifest(
"backends/go-godror/manifest.toml",
DEFAULT_MANIFEST_TOML,
)?;
Ok(Self { manifest })
}
}
impl CodegenBackend for GoGodrorBackend {
fn name(&self) -> &str {
"go-godror"
}
fn manifest(&self) -> &scythe_backend::manifest::BackendManifest {
&self.manifest
}
fn supported_engines(&self) -> &[&str] {
&["oracle"]
}
fn file_header(&self) -> String {
"// Code generated by scythe. DO NOT EDIT.\n// Run `goimports -w .` to fix imports.\npackage queries\n\nimport (\n\t\"context\"\n\t\"database/sql\"\n\t\"time\"\n)\n"
.to_string()
}
fn generate_row_struct(
&self,
query_name: &str,
columns: &[ResolvedColumn],
) -> Result<String, ScytheError> {
let struct_name = row_struct_name(query_name, &self.manifest.naming);
let mut out = String::new();
let _ = writeln!(out, "type {} struct {{", struct_name);
for col in columns {
let field = to_pascal_case(&col.field_name);
let json_tag = &col.field_name;
let _ = writeln!(out, "\t{} {} `json:\"{}\"`", field, col.full_type, json_tag);
}
let _ = write!(out, "}}");
Ok(out)
}
fn generate_model_struct(
&self,
table_name: &str,
columns: &[ResolvedColumn],
) -> Result<String, ScytheError> {
let name = to_pascal_case(table_name);
self.generate_row_struct(&name, columns)
}
fn generate_query_fn(
&self,
analyzed: &AnalyzedQuery,
struct_name: &str,
columns: &[ResolvedColumn],
params: &[ResolvedParam],
) -> Result<String, ScytheError> {
let func_name = fn_name(&analyzed.name, &self.manifest.naming);
let sql = super::rewrite_pg_placeholders(
&super::clean_sql_oneline_with_optional(
&analyzed.sql,
&analyzed.optional_params,
&analyzed.params,
),
|n| format!(":{n}"),
);
let param_list = params
.iter()
.map(|p| format!("{} {}", p.field_name, p.full_type))
.collect::<Vec<_>>()
.join(", ");
let sep = if param_list.is_empty() { "" } else { ", " };
let args = if params.is_empty() {
String::new()
} else {
format!(
", {}",
params
.iter()
.map(|p| p.field_name.clone())
.collect::<Vec<_>>()
.join(", ")
)
};
let has_returning = sql.to_uppercase().contains("RETURNING");
let mut out = String::new();
match &analyzed.command {
QueryCommand::One | QueryCommand::Opt => {
let _ = writeln!(
out,
"func {}(ctx context.Context, db *sql.DB{}{}) (*{}, error) {{",
func_name, sep, param_list, struct_name
);
if has_returning {
for col in columns {
let go_type = match col.neutral_type.as_str() {
"int32" => "int32",
"int64" => "int64",
"float32" | "float64" | "decimal" => "float64",
"date" | "datetime" | "datetime_tz" | "time" | "time_tz" => "time.Time",
_ => "string",
};
let _ = writeln!(
out,
"\tvar out{} {}",
to_pascal_case(&col.field_name),
go_type
);
}
let into_clause = columns
.iter()
.enumerate()
.map(|(i, _)| format!(":{}", params.len() + i + 1))
.collect::<Vec<_>>()
.join(", ");
let full_sql = format!("{} INTO {}", sql, into_clause);
let out_args: String = columns
.iter()
.map(|c| {
format!(", sql.Out{{Dest: &out{}}}", to_pascal_case(&c.field_name))
})
.collect();
let _ = writeln!(
out,
"\tif _, err := db.ExecContext(ctx, \"{}\"{}{}); err != nil {{",
full_sql, args, out_args
);
let _ = writeln!(out, "\t\treturn nil, err");
let _ = writeln!(out, "\t}}");
let _ = writeln!(out, "\treturn &{}{{{}}}, nil", struct_name, {
columns
.iter()
.map(|c| {
format!(
"{}: out{}",
to_pascal_case(&c.field_name),
to_pascal_case(&c.field_name)
)
})
.collect::<Vec<_>>()
.join(", ")
});
let _ = write!(out, "}}");
} else {
let _ = writeln!(out, "\trow := db.QueryRowContext(ctx, \"{}\"{})", sql, args);
let _ = writeln!(out, "\tvar item {}", struct_name);
let scan_fields: Vec<String> = columns
.iter()
.map(|c| format!("&item.{}", to_pascal_case(&c.field_name)))
.collect();
let _ = writeln!(
out,
"\tif err := row.Scan({}); err != nil {{",
scan_fields.join(", ")
);
let _ = writeln!(out, "\t\tif err == sql.ErrNoRows {{");
let _ = writeln!(out, "\t\t\treturn nil, nil");
let _ = writeln!(out, "\t\t}}");
let _ = writeln!(out, "\t\treturn nil, err");
let _ = writeln!(out, "\t}}");
let _ = writeln!(out, "\treturn &item, nil");
let _ = write!(out, "}}");
}
}
QueryCommand::Many => {
let _ = writeln!(
out,
"func {}(ctx context.Context, db *sql.DB{}{}) ([]{}, error) {{",
func_name, sep, param_list, struct_name
);
let _ = writeln!(
out,
"\trows, err := db.QueryContext(ctx, \"{}\"{})",
sql, args
);
let _ = writeln!(out, "\tif err != nil {{");
let _ = writeln!(out, "\t\treturn nil, err");
let _ = writeln!(out, "\t}}");
let _ = writeln!(out, "\tdefer rows.Close()");
let _ = writeln!(out, "\tvar items []{}", struct_name);
let _ = writeln!(out, "\tfor rows.Next() {{");
let _ = writeln!(out, "\t\tvar item {}", struct_name);
let scan_fields: Vec<String> = columns
.iter()
.map(|c| format!("&item.{}", to_pascal_case(&c.field_name)))
.collect();
let _ = writeln!(
out,
"\t\tif err := rows.Scan({}); err != nil {{",
scan_fields.join(", ")
);
let _ = writeln!(out, "\t\t\treturn nil, err");
let _ = writeln!(out, "\t\t}}");
let _ = writeln!(out, "\t\titems = append(items, item)");
let _ = writeln!(out, "\t}}");
let _ = writeln!(out, "\treturn items, rows.Err()");
let _ = write!(out, "}}");
}
QueryCommand::Exec => {
let _ = writeln!(
out,
"func {}(ctx context.Context, db *sql.DB{}{}) error {{",
func_name, sep, param_list
);
let _ = writeln!(out, "\t_, err := db.ExecContext(ctx, \"{}\"{})", sql, args);
let _ = writeln!(out, "\treturn err");
let _ = write!(out, "}}");
}
QueryCommand::ExecResult | QueryCommand::ExecRows => {
let _ = writeln!(
out,
"func {}(ctx context.Context, db *sql.DB{}{}) (int64, error) {{",
func_name, sep, param_list
);
let _ = writeln!(
out,
"\tresult, err := db.ExecContext(ctx, \"{}\"{})",
sql, args
);
let _ = writeln!(out, "\tif err != nil {{");
let _ = writeln!(out, "\t\treturn 0, err");
let _ = writeln!(out, "\t}}");
let _ = writeln!(out, "\treturn result.RowsAffected()");
let _ = write!(out, "}}");
}
QueryCommand::Batch => {
let batch_fn_name = format!("{}Batch", func_name);
let _ = writeln!(
out,
"func {}(ctx context.Context, db *sql.DB, items [][]any) error {{",
batch_fn_name
);
let _ = writeln!(out, "\ttx, err := db.BeginTx(ctx, nil)");
let _ = writeln!(out, "\tif err != nil {{");
let _ = writeln!(out, "\t\treturn err");
let _ = writeln!(out, "\t}}");
let _ = writeln!(out, "\tstmt, err := tx.PrepareContext(ctx, \"{}\")", sql);
let _ = writeln!(out, "\tif err != nil {{");
let _ = writeln!(out, "\t\t_ = tx.Rollback()");
let _ = writeln!(out, "\t\treturn err");
let _ = writeln!(out, "\t}}");
let _ = writeln!(out, "\tdefer stmt.Close()");
let _ = writeln!(out, "\tfor _, item := range items {{");
let _ = writeln!(
out,
"\t\tif _, err := stmt.ExecContext(ctx, item...); err != nil {{"
);
let _ = writeln!(out, "\t\t\t_ = tx.Rollback()");
let _ = writeln!(out, "\t\t\treturn err");
let _ = writeln!(out, "\t\t}}");
let _ = writeln!(out, "\t}}");
let _ = writeln!(out, "\treturn tx.Commit()");
let _ = write!(out, "}}");
}
QueryCommand::Grouped => unreachable!("Grouped is rewritten to Many before codegen"),
}
Ok(out)
}
fn generate_enum_def(&self, enum_info: &EnumInfo) -> Result<String, ScytheError> {
let type_name = enum_type_name(&enum_info.sql_name, &self.manifest.naming);
let mut out = String::new();
let _ = writeln!(out, "type {} string", type_name);
let _ = writeln!(out);
let _ = writeln!(out, "const (");
for value in &enum_info.values {
let variant = enum_variant_name(value, &self.manifest.naming);
let _ = writeln!(
out,
"\t{}{} {} = \"{}\"",
type_name, variant, type_name, value
);
}
let _ = write!(out, ")");
Ok(out)
}
fn generate_composite_def(&self, composite: &CompositeInfo) -> Result<String, ScytheError> {
let name = to_pascal_case(&composite.sql_name);
let mut out = String::new();
let _ = writeln!(out, "type {} struct {{", name);
for field in &composite.fields {
let go_type = resolve_type(&field.neutral_type, &self.manifest, false)
.map(|t| t.into_owned())
.unwrap_or_else(|_| "any".to_string());
let _ = writeln!(out, "\t{} {}", to_pascal_case(&field.name), go_type);
}
let _ = write!(out, "}}");
Ok(out)
}
}