From ac7d9e8031b4df489a0d58dc3459bc931f1ff870 Mon Sep 17 00:00:00 2001 From: Dirkjan Ochtman Date: Mon, 2 Nov 2020 14:26:17 +0100 Subject: Improve error handling (see #368) --- askama_shared/src/input.rs | 87 +++++++++++++++++++++++++--------------------- 1 file changed, 48 insertions(+), 39 deletions(-) (limited to 'askama_shared/src/input.rs') diff --git a/askama_shared/src/input.rs b/askama_shared/src/input.rs index f9d10a4..ca4015a 100644 --- a/askama_shared/src/input.rs +++ b/askama_shared/src/input.rs @@ -1,6 +1,7 @@ -use crate::{Config, Syntax}; +use crate::{CompileError, Config, Syntax}; use std::path::PathBuf; +use std::str::FromStr; use quote::ToTokens; @@ -21,7 +22,10 @@ impl<'a> TemplateInput<'a> { /// mostly recovers the data for the `TemplateInput` fields from the /// `template()` attribute list fields; it also finds the of the `_parent` /// field, if any. - pub fn new<'n>(ast: &'n syn::DeriveInput, config: &'n Config) -> TemplateInput<'n> { + pub fn new<'n>( + ast: &'n syn::DeriveInput, + config: &'n Config, + ) -> Result, CompileError> { // Check that an attribute called `template()` exists and that it is // the proper type (list). let meta = ast @@ -30,18 +34,18 @@ impl<'a> TemplateInput<'a> { .find_map(|attr| match attr.parse_meta() { Ok(m) => { if m.path().is_ident("template") { - Some(m) + Some(Ok(m)) } else { None } } - Err(e) => panic!("unable to parse attribute: {}", e), + Err(e) => Some(Err(format!("unable to parse attribute: {}", e).into())), }) - .expect("no attribute 'template' found"); + .unwrap_or(Err(CompileError::Static("no attribute 'template' found")))?; let meta_list = match meta { syn::Meta::List(inner) => inner, - _ => panic!("attribute 'template' has incorrect type"), + _ => return Err("attribute 'template' has incorrect type".into()), }; // Loop over the meta attributes and find everything that we @@ -55,59 +59,63 @@ impl<'a> TemplateInput<'a> { for item in meta_list.nested { let pair = match item { syn::NestedMeta::Meta(syn::Meta::NameValue(ref pair)) => pair, - _ => panic!( - "unsupported attribute argument {:?}", - item.to_token_stream() - ), + _ => { + return Err(format!( + "unsupported attribute argument {:?}", + item.to_token_stream() + ) + .into()) + } }; if pair.path.is_ident("path") { if let syn::Lit::Str(ref s) = pair.lit { if source.is_some() { - panic!("must specify 'source' or 'path', not both"); + return Err("must specify 'source' or 'path', not both".into()); } source = Some(Source::Path(s.value())); } else { - panic!("template path must be string literal"); + return Err("template path must be string literal".into()); } } else if pair.path.is_ident("source") { if let syn::Lit::Str(ref s) = pair.lit { if source.is_some() { - panic!("must specify 'source' or 'path', not both"); + return Err("must specify 'source' or 'path', not both".into()); } source = Some(Source::Source(s.value())); } else { - panic!("template source must be string literal"); + return Err("template source must be string literal".into()); } } else if pair.path.is_ident("print") { if let syn::Lit::Str(ref s) = pair.lit { - print = s.value().into(); + print = s.value().parse()?; } else { - panic!("print value must be string literal"); + return Err("print value must be string literal".into()); } } else if pair.path.is_ident("escape") { if let syn::Lit::Str(ref s) = pair.lit { escaping = Some(s.value()); } else { - panic!("escape value must be string literal"); + return Err("escape value must be string literal".into()); } } else if pair.path.is_ident("ext") { if let syn::Lit::Str(ref s) = pair.lit { ext = Some(s.value()); } else { - panic!("ext value must be string literal"); + return Err("ext value must be string literal".into()); } } else if pair.path.is_ident("syntax") { if let syn::Lit::Str(ref s) = pair.lit { syntax = Some(s.value()) } else { - panic!("syntax value must be string literal"); + return Err("syntax value must be string literal".into()); } } else { - panic!( + return Err(format!( "unsupported attribute key '{}' found", pair.path.to_token_stream() ) + .into()); } } @@ -116,13 +124,13 @@ impl<'a> TemplateInput<'a> { // of `ext` is merged into a synthetic `path` value here. let source = source.expect("template path or source not found in attributes"); let path = match (&source, &ext) { - (&Source::Path(ref path), None) => config.find_template(path, None), + (&Source::Path(ref path), None) => config.find_template(path, None)?, (&Source::Source(_), Some(ext)) => PathBuf::from(format!("{}.{}", ast.ident, ext)), (&Source::Path(_), Some(_)) => { - panic!("'ext' attribute cannot be used with 'path' attribute") + return Err("'ext' attribute cannot be used with 'path' attribute".into()) } (&Source::Source(_), None) => { - panic!("must include 'ext' attribute when using 'source' attribute") + return Err("must include 'ext' attribute when using 'source' attribute".into()) } }; @@ -149,14 +157,13 @@ impl<'a> TemplateInput<'a> { // Validate syntax let syntax = syntax.map_or_else( - || config.syntaxes.get(config.default_syntax).unwrap(), + || Ok(config.syntaxes.get(config.default_syntax).unwrap()), |s| { - config - .syntaxes - .get(&s) - .unwrap_or_else(|| panic!("attribute syntax {} not exist", s)) + config.syntaxes.get(&s).ok_or_else(|| { + CompileError::String(format!("attribute syntax {} not exist", s)) + }) }, - ); + )?; // Match extension against defined output formats @@ -175,11 +182,11 @@ impl<'a> TemplateInput<'a> { } } - let escaper = escaper.unwrap_or_else(|| { - panic!("no escaper defined for extension '{}'", extension); - }); + let escaper = escaper.ok_or_else(|| { + CompileError::String(format!("no escaper defined for extension '{}'", extension,)) + })?; - TemplateInput { + Ok(TemplateInput { ast, config, source, @@ -189,7 +196,7 @@ impl<'a> TemplateInput<'a> { parent, path, syntax, - } + }) } } @@ -206,15 +213,17 @@ pub enum Print { None, } -impl From for Print { - fn from(s: String) -> Print { +impl FromStr for Print { + type Err = CompileError; + + fn from_str(s: &str) -> Result { use self::Print::*; - match s.as_ref() { + Ok(match s { "all" => All, "ast" => Ast, "code" => Code, "none" => None, - v => panic!("invalid value for print option: {}", v), - } + v => return Err(format!("invalid value for print option: {}", v,).into()), + }) } } -- cgit