From eb76179dc4f6ea5ee3780a538ddf25b6ab6e8183 Mon Sep 17 00:00:00 2001
From: alankritdabral_2 <149957793+AlooDon@users.noreply.github.com>
Date: Mon, 20 Nov 2023 18:48:26 +0530
Subject: [PATCH] feat: add format_rustcode.sh script

This script makes it possible to check formatting of rust code found in the various markdown files in the repo. It is also added as a job to the QC CI workflow.
---
 .github/workflows/qc.yaml |   8 +++
 format_rust_code.sh       | 115 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 123 insertions(+)
 create mode 100755 format_rust_code.sh

diff --git a/.github/workflows/qc.yaml b/.github/workflows/qc.yaml
index 173c0d5..eda617a 100644
--- a/.github/workflows/qc.yaml
+++ b/.github/workflows/qc.yaml
@@ -25,6 +25,14 @@ jobs:
       - name: Run ShellCheck
         uses: ludeeus/action-shellcheck@master
 
+  rustfmt:
+    name: Rust Format
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Run Rust Formatting Script
+        run: bash format_rust_code.sh --mode check
+
   cargo-audit:
     runs-on: ubuntu-latest
     steps:
diff --git a/format_rust_code.sh b/format_rust_code.sh
new file mode 100755
index 0000000..b5cc10f
--- /dev/null
+++ b/format_rust_code.sh
@@ -0,0 +1,115 @@
+#!/usr/bin/env bash
+
+# Parse command line options
+while [[ $# -gt 0 ]]; do
+    case "$1" in
+        --mode)
+            mode="$2"
+            shift 2
+            ;;
+        *)
+            echo "Unknown option: $1"
+            exit 1
+            ;;
+    esac
+done
+
+# Check if mode is specified
+if [ -z "$mode" ]; then
+    echo "Please specify the mode using --mode option. Valid modes are 'check' and 'fix'."
+    exit 1
+fi
+
+# Find all Markdown files in the current directory and its subdirectories
+mapfile -t md_files < <(find . -type f -name "*.md")
+
+count=0
+# Iterate through each Markdown file
+for file in "${md_files[@]}"; do
+    # Use awk to extract Rust code blocks enclosed within triple backticks
+    rust_code_blocks=$(awk '/```rust/{flag=1; next}/```/{flag=0} flag' "$file")
+
+    # Count the number of Rust code blocks
+    num_fences=$(awk '/```rust/{f=1} f{if(/```/){f=0; count++}} END{print count}' "$file")
+
+    if [ -n "$rust_code_blocks" ]; then
+        echo "Processing Rust code in $file"
+        # Iterate through each Rust code block
+        for ((i=1; i <= num_fences ; i++)); do
+            # Extract individual Rust code block using awk
+            current_rust_block=$(awk -v i="$i" '/```rust/{f=1; if (++count == i) next} f&&/```/{f=0;next} f' "$file")
+            # Variable to check if we have added the main function
+            add_main=0  
+            # Check if the Rust code block is already inside a function
+            if ! echo "$current_rust_block" | grep -q "fn main()"; then
+                # If not, wrap it in a main function
+                current_rust_block=$'fn main() {\n'"$current_rust_block"$'\n}'
+                add_main=1
+            fi
+            if [ "$mode" == "check" ]; then
+                # Apply changes to the Rust code block
+                formatted_rust_code=$(echo "$current_rust_block" | rustfmt)
+                # Use rustfmt to format the Rust code block, remove first and last lines, and remove the first 4 spaces if added  main function
+                if [ "$add_main" == 1 ]; then
+                    formatted_rust_code=$(echo "$formatted_rust_code" | sed '1d;$d' | sed 's/^    //')
+                    current_rust_block=$(echo "$current_rust_block" | sed '1d;')
+                    current_rust_block=$(echo "$current_rust_block" | sed '$d')
+                fi
+                if [ "$formatted_rust_code" == "$current_rust_block" ]; then
+                    echo "No changes needed in Rust code block $i in $file"
+                else
+                    echo -e "\nChanges needed in Rust code block $i in $file:\n"
+                    echo "$formatted_rust_code"
+                    count=+1
+                fi
+
+            elif [ "$mode" == "fix" ]; then
+                # Replace current_rust_block with formatted_rust_code in the file
+                formatted_rust_code=$(echo "$current_rust_block" | rustfmt)
+                # Use rustfmt to format the Rust code block, remove first and last lines, and remove the first 4 spaces if added  main function
+                if [ "$add_main" == 1 ]; then
+                    formatted_rust_code=$(echo "$formatted_rust_code" | sed '1d;$d' | sed 's/^    //')
+                    current_rust_block=$(echo "$current_rust_block" | sed '1d;')
+                    current_rust_block=$(echo "$current_rust_block" | sed '$d')
+                fi
+                # Check if the formatted code is the same as the current Rust code block
+                if [ "$formatted_rust_code" == "$current_rust_block" ]; then
+                    echo "No changes needed in Rust code block $i in $file"
+                else
+                    echo "Formatting Rust code block $i in $file"
+                    # Replace current_rust_block with formatted_rust_code in the file
+                    # Use awk to find the line number of the pattern
+
+                    start_line=$(grep -n "^\`\`\`rust" "$file" | sed -n "${i}p" | cut -d: -f1)
+                    end_line=$(grep -n "^\`\`\`" "$file" | awk -F: -v start_line="$start_line" '$1 > start_line {print $1; exit;}')
+
+                    if [ -n "$start_line" ] && [ -n "$end_line" ]; then
+                        # Print lines before the Rust code block
+                        head -n "$((start_line - 1))" "$file"
+
+                        # Print the formatted Rust code block
+                        echo "\`\`\`rust"
+                        echo "$formatted_rust_code"
+                        echo "\`\`\`"
+
+                        # Print lines after the Rust code block
+                        tail -n +"$((end_line + 1))" "$file"
+                    else
+                        # Rust code block not found or end line not found
+                        cat "$file"
+                    fi > tmpfile && mv tmpfile "$file"
+
+                fi
+            else  
+                echo "Unknown mode: $mode. Valid modes are 'check' and 'fix'."
+                exit 1
+            fi
+        done
+    fi
+done
+
+# CI failure if changes are needed
+if [ $count -gt 0 ]; then
+    echo "CI failed: Changes needed in Rust code blocks."
+    exit 1
+fi