Optimize config.ini updates by batching shell executions

- Reduce up to 5 separate shell executions to 1 for AVD configuration
- Improves performance by eliminating redundant process spawns
- Add comprehensive efficiency report documenting all identified improvements
- All existing tests pass, no functional changes

Co-Authored-By: Yang <[email protected]>

Author: devin-ai-integration[bot]

EFFICIENCY_REPORT.md

@@ -0,0 +1,59 @@
+# Android Emulator Runner - Efficiency Improvements Report
+
+## Overview
+This report documents efficiency improvements identified in the Android Emulator Runner codebase. The analysis focused on finding opportunities to reduce redundant operations, optimize I/O, and improve overall performance.
+
+## Identified Inefficiencies
+
+### 1. Multiple Shell Executions for Config.ini Updates (HIGH IMPACT) ⚡
+**File:** `src/emulator-manager.ts` (Lines 40-58)
+**Issue:** The code executes up to 5 separate shell commands to append configuration entries to the AVD config.ini file.
+**Impact:** Each shell execution spawns a new process, which is expensive. When multiple config options are set, this results in 5 separate process spawns.
+**Solution:** Batch all configuration entries into a single shell command.
+**Performance Gain:** Reduces shell executions from 5 to 1 (up to 80% reduction in process spawns).
+
+### 2. Inefficient Channel Mapping (MEDIUM IMPACT)
+**File:** `src/channel-id-mapper.ts` (Lines 1-13)
+**Issue:** Uses if-else chain instead of a lookup table/map for channel name to ID mapping.
+**Impact:** O(n) lookup time instead of O(1), though with only 4 channels the impact is minimal.
+**Solution:** Replace with a Map or object lookup.
+**Performance Gain:** Constant time lookup instead of linear search.
+
+### 3. Repeated Number Conversions (LOW IMPACT)
+**File:** `src/input-validator.ts` (Lines 79, 92, 97)
+**Issue:** The `checkEmulatorBuild` and `checkDiskSize` functions call `Number()` multiple times on the same string.
+**Impact:** Unnecessary computation overhead.
+**Solution:** Store the converted number in a variable and reuse it.
+**Performance Gain:** Eliminates redundant type conversions.
+
+### 4. Regex Creation on Every Function Call (LOW IMPACT)
+**File:** `src/script-parser.ts` (Line 7)
+**Issue:** Creates regex `/\r\n|\n|\r/` on every `parseScript` function call.
+**Impact:** Regex compilation overhead on each invocation.
+**Solution:** Define regex as a module-level constant.
+**Performance Gain:** Eliminates regex recompilation.
+
+### 5. Redundant Boolean Validation Functions (LOW IMPACT)
+**File:** `src/input-validator.ts` (Lines 39-76)
+**Issue:** Multiple similar validation functions that all use the same `isValidBoolean` helper.
+**Impact:** Code duplication and maintenance overhead.
+**Solution:** Create a generic boolean validator function.
+**Performance Gain:** Reduced code size and improved maintainability.
+
+## Implementation Priority
+
+1. **HIGH PRIORITY:** Config.ini shell execution batching (implemented in this PR)
+2. **MEDIUM PRIORITY:** Channel mapping optimization
+3. **LOW PRIORITY:** Number conversion optimization
+4. **LOW PRIORITY:** Regex constant optimization
+5. **LOW PRIORITY:** Boolean validation consolidation
+
+## Performance Impact Summary
+
+The primary fix implemented in this PR (batching config.ini updates) provides the most significant performance improvement by reducing shell process spawns from up to 5 to 1. This is particularly beneficial when multiple AVD configuration options are specified, which is a common use case.
+
+The other identified inefficiencies have lower impact but could be addressed in future optimization efforts for marginal performance gains and improved code maintainability.
+
+## Testing
+
+All existing tests pass with the implemented changes, ensuring no functional regressions while providing performance benefits.

src/emulator-manager.ts

@@ -37,24 +37,29 @@ export async function launchEmulator(
       );
     }
 
-    if (cores) {
-      await exec.exec(`sh -c \\"printf 'hw.cpu.ncore=${cores}\n' >> ${process.env.ANDROID_AVD_HOME}/"${avdName}".avd"/config.ini`);
-    }
-
-    if (ramSize) {
-      await exec.exec(`sh -c \\"printf 'hw.ramSize=${ramSize}\n' >> ${process.env.ANDROID_AVD_HOME}/"${avdName}".avd"/config.ini`);
-    }
+    if (cores || ramSize || heapSize || enableHardwareKeyboard || diskSize) {
+      const configEntries: string[] = [];
 
-    if (heapSize) {
-      await exec.exec(`sh -c \\"printf 'hw.heapSize=${heapSize}\n' >> ${process.env.ANDROID_AVD_HOME}/"${avdName}".avd"/config.ini`);
-    }
-
-    if (enableHardwareKeyboard) {
-      await exec.exec(`sh -c \\"printf 'hw.keyboard=yes\n' >> ${process.env.ANDROID_AVD_HOME}/"${avdName}".avd"/config.ini`);
-    }
+      if (cores) {
+        configEntries.push(`hw.cpu.ncore=${cores}`);
+      }
+      if (ramSize) {
+        configEntries.push(`hw.ramSize=${ramSize}`);
+      }
+      if (heapSize) {
+        configEntries.push(`hw.heapSize=${heapSize}`);
+      }
+      if (enableHardwareKeyboard) {
+        configEntries.push('hw.keyboard=yes');
+      }
+      if (diskSize) {
+        configEntries.push(`disk.dataPartition.size=${diskSize}`);
+      }
 
-    if (diskSize) {
-      await exec.exec(`sh -c \\"printf 'disk.dataPartition.size=${diskSize}\n' >> ${process.env.ANDROID_AVD_HOME}/"${avdName}".avd"/config.ini`);
+      if (configEntries.length > 0) {
+        const configContent = configEntries.join('\\n') + '\\n';
+        await exec.exec(`sh -c \\"printf '${configContent}' >> ${process.env.ANDROID_AVD_HOME}/"${avdName}".avd"/config.ini"`);
+      }
     }
 
     // turn off hardware acceleration on Linux