From eb460333907a44c37bf7287b31c653877c3358c2 Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Fri, 6 Nov 2020 19:01:25 +0100
Subject: [PATCH] More orthogonal API

---
 .../src/handlers/convert_integer_literal.rs   | 23 +++----
 crates/syntax/src/ast/token_ext.rs            | 63 +++++++++----------
 2 files changed, 38 insertions(+), 48 deletions(-)

diff --git a/crates/assists/src/handlers/convert_integer_literal.rs b/crates/assists/src/handlers/convert_integer_literal.rs
index 6d477c045e4..5957834d307 100644
--- a/crates/assists/src/handlers/convert_integer_literal.rs
+++ b/crates/assists/src/handlers/convert_integer_literal.rs
@@ -1,4 +1,4 @@
-use syntax::{ast, ast::Radix, AstNode};
+use syntax::{ast, ast::Radix, AstToken};
 
 use crate::{AssistContext, AssistId, AssistKind, Assists, GroupLabel};
 
@@ -14,15 +14,13 @@ use crate::{AssistContext, AssistId, AssistKind, Assists, GroupLabel};
 // const _: i32 = 0b1010;
 // ```
 pub(crate) fn convert_integer_literal(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
-    let literal = ctx.find_node_at_offset::<ast::Literal>()?;
-    let (radix, value) = literal.as_int_number()?.value()?;
+    let literal = ctx.find_node_at_offset::<ast::Literal>()?.as_int_number()?;
+    let radix = literal.radix();
+    let value = literal.value()?;
+    let suffix = literal.suffix();
 
     let range = literal.syntax().text_range();
     let group_id = GroupLabel("Convert integer base".into());
-    let suffix = match literal.kind() {
-        ast::LiteralKind::IntNumber { suffix } => suffix,
-        _ => return None,
-    };
 
     for &target_radix in Radix::ALL {
         if target_radix == radix {
@@ -36,16 +34,11 @@ pub(crate) fn convert_integer_literal(acc: &mut Assists, ctx: &AssistContext) ->
             Radix::Hexadecimal => format!("0x{:X}", value),
         };
 
-        let label = format!(
-            "Convert {} to {}{}",
-            literal,
-            converted,
-            suffix.as_deref().unwrap_or_default()
-        );
+        let label = format!("Convert {} to {}{}", literal, converted, suffix.unwrap_or_default());
 
         // Appends the type suffix back into the new literal if it exists.
-        if let Some(suffix) = &suffix {
-            converted.push_str(&suffix);
+        if let Some(suffix) = suffix {
+            converted.push_str(suffix);
         }
 
         acc.add_group(
diff --git a/crates/syntax/src/ast/token_ext.rs b/crates/syntax/src/ast/token_ext.rs
index 5623799b475..8d3fad5a6c6 100644
--- a/crates/syntax/src/ast/token_ext.rs
+++ b/crates/syntax/src/ast/token_ext.rs
@@ -166,6 +166,7 @@ impl HasStringValue for ast::String {
     }
 }
 
+// FIXME: merge `ast::RawString` and `ast::String`.
 impl HasStringValue for ast::RawString {
     fn value(&self) -> Option<Cow<'_, str>> {
         let text = self.text().as_str();
@@ -544,29 +545,46 @@ impl ast::IntNumber {
         "i8", "i16", "i32", "i64", "i128", "isize",
     ];
 
-    // FIXME: should probably introduce string token type?
-    // https://github.com/rust-analyzer/rust-analyzer/issues/6308
-    pub fn value(&self) -> Option<(Radix, u128)> {
+    pub fn radix(&self) -> Radix {
+        match self.text().get(..2).unwrap_or_default() {
+            "0b" => Radix::Binary,
+            "0o" => Radix::Octal,
+            "0x" => Radix::Hexadecimal,
+            _ => Radix::Decimal,
+        }
+    }
+
+    pub fn value(&self) -> Option<u128> {
         let token = self.syntax();
 
         let mut text = token.text().as_str();
-        for suffix in ast::IntNumber::SUFFIXES {
-            if let Some(without_suffix) = text.strip_suffix(suffix) {
-                text = without_suffix;
-                break;
-            }
+        if let Some(suffix) = self.suffix() {
+            text = &text[..text.len() - suffix.len()]
         }
 
+        let radix = self.radix();
+        text = &text[radix.prefix_len()..];
+
         let buf;
         if text.contains("_") {
             buf = text.replace('_', "");
             text = buf.as_str();
         };
 
-        let radix = Radix::identify(text)?;
-        let digits = &text[radix.prefix_len()..];
-        let value = u128::from_str_radix(digits, radix as u32).ok()?;
-        Some((radix, value))
+        let value = u128::from_str_radix(text, radix as u32).ok()?;
+        Some(value)
+    }
+
+    pub fn suffix(&self) -> Option<&str> {
+        let text = self.text();
+        // FIXME: don't check a fixed set of suffixes, `1_0_1___lol` is valid
+        // syntax, suffix is `lol`.
+        ast::IntNumber::SUFFIXES.iter().find_map(|suffix| {
+            if text.ends_with(suffix) {
+                return Some(&text[text.len() - suffix.len()..]);
+            }
+            None
+        })
     }
 }
 
@@ -586,27 +604,6 @@ impl Radix {
     pub const ALL: &'static [Radix] =
         &[Radix::Binary, Radix::Octal, Radix::Decimal, Radix::Hexadecimal];
 
-    fn identify(literal_text: &str) -> Option<Self> {
-        // We cannot express a literal in anything other than decimal in under 3 characters, so we return here if possible.
-        if literal_text.len() < 3 && literal_text.chars().all(|c| c.is_digit(10)) {
-            return Some(Self::Decimal);
-        }
-
-        let res = match &literal_text[..2] {
-            "0b" => Radix::Binary,
-            "0o" => Radix::Octal,
-            "0x" => Radix::Hexadecimal,
-            _ => Radix::Decimal,
-        };
-
-        // Checks that all characters after the base prefix are all valid digits for that base.
-        if literal_text[res.prefix_len()..].chars().all(|c| c.is_digit(res as u32)) {
-            Some(res)
-        } else {
-            None
-        }
-    }
-
     const fn prefix_len(&self) -> usize {
         match self {
             Self::Decimal => 0,