Introduce OutputCache file

This file should cache warnings and other compiler output between compilations.
Directly maps to ctx.OutputCache map

Author: facchinm

Diff for: builder.go

@@ -129,6 +129,8 @@ func (s *Builder) Run(ctx *types.Context) error {
 
 		&PrintUsedLibrariesIfVerbose{},
 
+		&StoreOutputCacheMap{},
+
 		&ExportProjectCMake{SketchError: mainErr != nil},
 
 		&phases.Sizer{SketchError: mainErr != nil},

Diff for: constants/constants.go

@@ -90,6 +90,7 @@ const FILE_PLATFORM_LOCAL_TXT = "platform.local.txt"
 const FILE_PLATFORM_TXT = "platform.txt"
 const FILE_PROGRAMMERS_TXT = "programmers.txt"
 const FILE_INCLUDES_CACHE = "includes.cache"
+const FILE_OUTPUT_CACHE = "output.cache"
 const FOLDER_BOOTLOADERS = "bootloaders"
 const FOLDER_CORE = "core"
 const FOLDER_CORES = "cores"

Diff for: container_build_options.go

@@ -41,6 +41,7 @@ func (s *ContainerBuildOptions) Run(ctx *types.Context) error {
 		&CreateBuildOptionsMap{},
 		&LoadPreviousBuildOptionsMap{},
 		&WipeoutBuildPathIfBuildOptionsChanged{},
+		&LoadPreviousOutputCacheMap{},
 		&StoreBuildOptionsMap{},
 	}
 

Diff for: load_previous_build_options.go

@@ -30,12 +30,14 @@
 package builder
 
 import (
-	"github.com/arduino/arduino-builder/constants"
-	"github.com/arduino/arduino-builder/i18n"
-	"github.com/arduino/arduino-builder/types"
+	"encoding/json"
 	"io/ioutil"
 	"os"
 	"path/filepath"
+
+	"github.com/arduino/arduino-builder/constants"
+	"github.com/arduino/arduino-builder/i18n"
+	"github.com/arduino/arduino-builder/types"
 )
 
 type LoadPreviousBuildOptionsMap struct{}
@@ -60,3 +62,27 @@ func (s *LoadPreviousBuildOptionsMap) Run(ctx *types.Context) error {
 
 	return nil
 }
+
+type LoadPreviousOutputCacheMap struct{}
+
+func (s *LoadPreviousOutputCacheMap) Run(ctx *types.Context) error {
+	cachedWarningsFile := filepath.Join(ctx.BuildPath, constants.FILE_OUTPUT_CACHE)
+	ctx.OutputCache = make(map[string]types.Streams)
+
+	_, err := os.Stat(cachedWarningsFile)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil
+		}
+		return i18n.WrapError(err)
+	}
+
+	bytes, err := ioutil.ReadFile(cachedWarningsFile)
+	if err != nil {
+		return i18n.WrapError(err)
+	}
+
+	json.Unmarshal(bytes, &ctx.OutputCache)
+
+	return nil
+}

Diff for: store_build_options_map.go

@@ -30,10 +30,12 @@
 package builder
 
 import (
+	"encoding/json"
+	"path/filepath"
+
 	"github.com/arduino/arduino-builder/constants"
 	"github.com/arduino/arduino-builder/types"
 	"github.com/arduino/arduino-builder/utils"
-	"path/filepath"
 )
 
 type StoreBuildOptionsMap struct{}
@@ -42,3 +44,11 @@ func (s *StoreBuildOptionsMap) Run(ctx *types.Context) error {
 	utils.WriteFile(filepath.Join(ctx.BuildPath, constants.BUILD_OPTIONS_FILE), ctx.BuildOptionsJson)
 	return nil
 }
+
+type StoreOutputCacheMap struct{}
+
+func (s *StoreOutputCacheMap) Run(ctx *types.Context) error {
+	data, _ := json.Marshal(ctx.OutputCache)
+	utils.WriteFile(filepath.Join(ctx.BuildPath, constants.FILE_OUTPUT_CACHE), string(data))
+	return nil
+}

Diff for: types/context.go

@@ -14,6 +14,11 @@ type ProgressStruct struct {
 	Progress     float64
 }
 
+type Streams struct {
+	Stdout []byte
+	Stderr []byte
+}
+
 // Context structure
 type Context struct {
 	// Build options
@@ -65,6 +70,7 @@ type Context struct {
 	CodeCompletions string
 
 	WarningsLevel string
+	OutputCache   map[string]Streams
 
 	// Libraries handling
 	Libraries                  []*Library