Refactor generateManifest infra tool

- Changed from using bash/perl to using go.
- Now "if" statements in .gjson files can be stacked, and there can be
  conditional "or" statements inside, like |#if defined(A || B)|.
- Go tests were added to make sure that the generateManifest tool
  continues to work as expected.
- Updated docs to reflect the fact that the manifest is now generated
  with a different tool, and Go is now required in the build phase.

Change-Id: Id866d1a49a7ab4aac2dcf8d188c56bb8254a80de
diff --git a/README.md b/README.md
index d0d6ee2..f5ab3eb 100644
--- a/README.md
+++ b/README.md
@@ -52,7 +52,8 @@
 ## Build the extension
 A zip file with the contents of the extension, which can be uploaded to the
 Chrome Web Store and addons.mozilla.org, can be created with any of the
-following procedures:
+following procedures (make sure to [install Go](https://golang.org) before
+building the extension, as it is needed during the build):
 
 ### Using the release.bash script
 Run `bash release.bash -h` in order to learn how to use this command. To
@@ -76,12 +77,12 @@
 ## Testing notes
 When testing the extension during development, you don't have to build the
 extension each time you want to import an updated version to Chrome/Firefox.
-Instead, run `bash generateManifest.bash {browser}` once, where `{browser}`
-is either `CHROMIUM` or `GECKO`, and this will generate a `manifest.json`
-file for the specified browser in the `src` directory. Now, you can load the
-`src` folder directly in the browser in order to import the extension, which
-removes the need to build it. When the `manifest.gjson` file is modified, you'll
-have to generate the manifest again.
+Instead, run `go run generateManifest.go {browser}` once, where `{browser}` is
+either `CHROMIUM` or `GECKO`, and this will generate a `manifest.json` file for
+the specified browser in the `src` directory. Now, you can load the `src` folder
+directly in the browser in order to import the extension, which removes the need
+to build it. When the `manifest.gjson` file is modified, you'll have to generate
+the manifest again.
 
 To test translations, you might want to set your browser's locale. This section
 tells you how to set the locale in
diff --git a/generateManifest.bash b/generateManifest.bash
deleted file mode 100644
index 29839c0..0000000
--- a/generateManifest.bash
+++ /dev/null
@@ -1,17 +0,0 @@
-#!/bin/bash
-#
-# Generates the manifest.json file according to the dependencies passed
-# via CLI arguments
-
-dependencies=("$@")
-
-rm -f src/manifest.json
-cp templates/manifest.gjson src/manifest.json
-
-for dep in "${dependencies[@]}"; do
-  perl -0777 -pi -e "s/^#if defined\($dep\)\n([^#]*)#endif\n/\$1/gms" \
-    src/manifest.json
-done
-
-perl -0777 -pi -e "s/^#if defined\([^\n#]+\)\n[^#]*#endif\n//gms" \
-  src/manifest.json
diff --git a/generateManifest.go b/generateManifest.go
new file mode 100644
index 0000000..1c2e4f0
--- /dev/null
+++ b/generateManifest.go
@@ -0,0 +1,107 @@
+package main
+
+import (
+  "bufio"
+  "flag"
+  "fmt"
+  "io"
+  "log"
+  "os"
+  "regexp"
+  "strings"
+)
+
+// Generates the manifest.json file according to the dependencies passed
+// via CLI arguments
+
+const (
+  manifestTemplate = "templates/manifest.gjson"
+  manifestSrc = "src/manifest.json"
+)
+
+var beginningOfIfStatement = regexp.MustCompile(`^\s*#if defined\(([^\(\)]*)\)\s*$`)
+var endOfIfStatement = regexp.MustCompile(`^\s*#endif\s*$`)
+
+var (
+  quietMode = flag.Bool("quiet", false, "Quiet mode")
+)
+
+func FindWithCaseFolding(slice []string, val string) bool {
+  for _, item := range slice {
+    if strings.EqualFold(item, val) {
+      return true
+    }
+  }
+  return false
+}
+
+func WriteManifest(template io.Reader, dest io.Writer, dependencies []string) error {
+  level := 0
+  activeLevel := 0
+  scanner := bufio.NewScanner(template)
+  for scanner.Scan() {
+    line := scanner.Text()
+    considerLine := false
+    if m := beginningOfIfStatement.FindStringSubmatch(line); m != nil {
+      if level == activeLevel {
+        statementDeps := m[1]
+        deps := strings.Split(statementDeps, "||")
+        for _, dep := range deps {
+          dep = strings.TrimSpace(dep)
+          if FindWithCaseFolding(dependencies, dep) {
+            activeLevel++
+            break
+          }
+        }
+      }
+      level++
+    } else if m := endOfIfStatement.MatchString(line); m {
+      if activeLevel == level {
+        activeLevel--
+      }
+      level--
+    } else {
+      considerLine = level == activeLevel
+    }
+
+    if considerLine {
+      _, err := io.WriteString(dest, line + "\n")
+      if err != nil {
+        return fmt.Errorf("Can't write manifest: %v", err)
+      }
+    }
+  }
+
+  return nil
+}
+
+func main() {
+  log.SetPrefix("generateManifest: ")
+  log.SetFlags(0)
+
+  flag.Parse()
+  dependencies := flag.Args()
+
+  if len(dependencies) == 0 {
+    log.Fatalf("Pass the dependencies as arguments (for instance, run `go run generateManifest.go CHROMIUM`).")
+  }
+
+  template, err := os.Open(manifestTemplate)
+  if err != nil {
+    log.Fatalf("Couldn't open file %v: %v", manifestTemplate, err)
+  }
+  defer template.Close()
+
+  dest, err := os.Create(manifestSrc)
+  if err != nil {
+    log.Fatalf("Couldn't create file %v: %v", manifestSrc, err)
+  }
+  defer dest.Close()
+
+  err = WriteManifest(template, dest, dependencies)
+  if err != nil {
+    log.Fatalf("%v", err)
+  } else if !*quietMode {
+    log.Println("Manifest has been generated successfully")
+  }
+}
diff --git a/generateManifest_test.go b/generateManifest_test.go
new file mode 100644
index 0000000..57f2f56
--- /dev/null
+++ b/generateManifest_test.go
@@ -0,0 +1,79 @@
+package main
+
+import (
+  "bytes"
+  "crypto/sha256"
+  "encoding/hex"
+  "io"
+  "os"
+  "testing"
+)
+
+type Manifest struct {
+  name string
+  templateFile string
+  expectedFile string
+  dependencies []string
+}
+
+func TestManifestConversions(t *testing.T) {
+  testManifests := []Manifest{
+    {
+      name: "ManifestSmall",
+      templateFile: "testdata/manifest_small1.gjson",
+      expectedFile: "testdata/manifest_small1_expected.json",
+      dependencies: []string{"AAA", "BBB", "D"},
+    },
+    {
+      name: "ManifestFrozenChromium",
+      templateFile: "testdata/manifest_frozen.gjson",
+      expectedFile: "testdata/manifest_frozen_chromium_expected.json",
+      dependencies: []string{"CHROMIUM"},
+    },
+    {
+      name: "ManifestFrozenGecko",
+      templateFile: "testdata/manifest_frozen.gjson",
+      expectedFile: "testdata/manifest_frozen_gecko_expected.json",
+      dependencies: []string{"GECKO"},
+    },
+  }
+
+  for _, m := range testManifests {
+    t.Run(m.name, func(t *testing.T) {
+      template, err := os.Open(m.templateFile)
+      if err != nil {
+        t.Fatalf("Can't open test file: %v", err)
+      }
+      defer template.Close()
+
+      expected, err := os.Open(m.expectedFile)
+      if err != nil {
+        t.Fatalf("Can't open expected file: %v", err)
+      }
+      defer expected.Close()
+
+      dest := bytes.NewBufferString("")
+
+      WriteManifest(template, dest, m.dependencies)
+      if err != nil {
+        t.Fatal(err)
+      }
+
+      h1 := sha256.New()
+      if _, err := io.Copy(h1, dest); err != nil {
+        t.Fatalf("Can't prepare sha256 sum of the result: %v", err)
+      }
+
+      h2 := sha256.New()
+      if _, err := io.Copy(h2, expected); err != nil {
+        t.Fatalf("Can't prepare sha256 sum of the expected file: %v", err)
+      }
+
+      sum1 := h1.Sum(nil)
+      sum2 := h2.Sum(nil)
+      if bytes.Compare(sum1, sum2) != 0 {
+        t.Fatalf("The expected manifest file (sha256: %v) differs from what we got (sha256: %v).", hex.EncodeToString(sum2), hex.EncodeToString(sum1))
+      }
+    })
+  }
+}
diff --git a/release.bash b/release.bash
index 75ac4aa..269bd4d 100644
--- a/release.bash
+++ b/release.bash
@@ -64,9 +64,9 @@
 
 # First of all, generate the appropriate manifest.json file for the
 # target browser
-dependencies=(${browser^^})
+dependencies=(${browser})
 
-bash generateManifest.bash "${dependencies[@]}"
+go run generateManifest.go "${dependencies[@]}"
 
 # This is the version name which git gives us
 version=$(git describe --always --tags --dirty)
diff --git a/testdata/manifest_frozen.gjson b/testdata/manifest_frozen.gjson
new file mode 100644
index 0000000..8d93b2e
--- /dev/null
+++ b/testdata/manifest_frozen.gjson
@@ -0,0 +1,89 @@
+{
+  "manifest_version": 2,
+  "name": "__MSG_appName__",
+  "version": "0",
+#if defined(CHROMIUM)
+  "version_name": "dirty",
+#endif
+  "description": "__MSG_appDescription__",
+  "icons": {
+    "512": "icons/512.png",
+    "128": "icons/128.png"
+  },
+  "content_scripts": [
+    {
+      "matches": ["https://support.google.com/s/community*"],
+      "js": ["common/content_scripts.js", "content_scripts/console_inject.js"]
+    },
+    {
+      "matches": ["https://support.google.com/s/community*"],
+      "js": ["common/content_scripts.js", "content_scripts/console_inject_start.js"],
+      "css": ["common/console.css"],
+      "run_at": "document_start"
+    },
+    {
+      "matches": ["https://support.google.com/*/threads*"],
+      "js": ["content_scripts/forum_inject.js"]
+    },
+    {
+      "matches": ["https://support.google.com/*/thread/*"],
+      "exclude_matches": ["https://support.google.com/s/community*", "https://support.google.com/*/thread/new*"],
+      "js": ["common/content_scripts.js", "content_scripts/thread_inject.js"],
+      "run_at": "document_end"
+    },
+    {
+      "matches": ["https://support.google.com/s/community*", "https://support.google.com/*/thread/*"],
+      "exclude_matches": ["https://support.google.com/*/thread/new*"],
+      "js": ["common/content_scripts.js", "common/cs_event_listener.js", "content_scripts/profileindicator_inject.js"]
+    },
+    {
+      "matches": ["https://support.google.com/*/profile/*"],
+      "js": ["common/content_scripts.js", "content_scripts/profile_inject.js"],
+      "css": ["common/forum.css"]
+    }
+  ],
+  "permissions": [
+    "https://support.google.com/s/community*",
+    "https://support.google.com/*/threads*",
+    "https://support.google.com/*/thread/*",
+    "storage"
+  ],
+  "web_accessible_resources": [
+    "injections/profileindicator_inject.js",
+    "injections/profileindicator_inject.css",
+    "injections/ccdarktheme.css",
+    "injections/batchlock_inject.js"
+  ],
+  "browser_action": {},
+#if defined(CHROMIUM)
+  "options_page": "options.html",
+#endif
+  "options_ui": {
+    "page": "options.html",
+#if defined(CHROMIUM)
+    "chrome_style": true,
+#endif
+#if defined(GECKO)
+    "browser_style": true,
+#endif
+    "open_in_tab": false
+  },
+  "background": {
+#if defined(CHROMIUM)
+    "persistent": false,
+#endif
+    "scripts": [
+      "common/common.js",
+      "background.js"
+    ]
+  },
+#if defined(GECKO)
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "twpowertools@avm99963.com",
+      "strict_min_version": "57.0"
+    }
+  },
+#endif
+  "default_locale": "en"
+}
diff --git a/testdata/manifest_frozen_chromium_expected.json b/testdata/manifest_frozen_chromium_expected.json
new file mode 100644
index 0000000..2bd184b
--- /dev/null
+++ b/testdata/manifest_frozen_chromium_expected.json
@@ -0,0 +1,70 @@
+{
+  "manifest_version": 2,
+  "name": "__MSG_appName__",
+  "version": "0",
+  "version_name": "dirty",
+  "description": "__MSG_appDescription__",
+  "icons": {
+    "512": "icons/512.png",
+    "128": "icons/128.png"
+  },
+  "content_scripts": [
+    {
+      "matches": ["https://support.google.com/s/community*"],
+      "js": ["common/content_scripts.js", "content_scripts/console_inject.js"]
+    },
+    {
+      "matches": ["https://support.google.com/s/community*"],
+      "js": ["common/content_scripts.js", "content_scripts/console_inject_start.js"],
+      "css": ["common/console.css"],
+      "run_at": "document_start"
+    },
+    {
+      "matches": ["https://support.google.com/*/threads*"],
+      "js": ["content_scripts/forum_inject.js"]
+    },
+    {
+      "matches": ["https://support.google.com/*/thread/*"],
+      "exclude_matches": ["https://support.google.com/s/community*", "https://support.google.com/*/thread/new*"],
+      "js": ["common/content_scripts.js", "content_scripts/thread_inject.js"],
+      "run_at": "document_end"
+    },
+    {
+      "matches": ["https://support.google.com/s/community*", "https://support.google.com/*/thread/*"],
+      "exclude_matches": ["https://support.google.com/*/thread/new*"],
+      "js": ["common/content_scripts.js", "common/cs_event_listener.js", "content_scripts/profileindicator_inject.js"]
+    },
+    {
+      "matches": ["https://support.google.com/*/profile/*"],
+      "js": ["common/content_scripts.js", "content_scripts/profile_inject.js"],
+      "css": ["common/forum.css"]
+    }
+  ],
+  "permissions": [
+    "https://support.google.com/s/community*",
+    "https://support.google.com/*/threads*",
+    "https://support.google.com/*/thread/*",
+    "storage"
+  ],
+  "web_accessible_resources": [
+    "injections/profileindicator_inject.js",
+    "injections/profileindicator_inject.css",
+    "injections/ccdarktheme.css",
+    "injections/batchlock_inject.js"
+  ],
+  "browser_action": {},
+  "options_page": "options.html",
+  "options_ui": {
+    "page": "options.html",
+    "chrome_style": true,
+    "open_in_tab": false
+  },
+  "background": {
+    "persistent": false,
+    "scripts": [
+      "common/common.js",
+      "background.js"
+    ]
+  },
+  "default_locale": "en"
+}
diff --git a/testdata/manifest_frozen_gecko_expected.json b/testdata/manifest_frozen_gecko_expected.json
new file mode 100644
index 0000000..49792d5
--- /dev/null
+++ b/testdata/manifest_frozen_gecko_expected.json
@@ -0,0 +1,73 @@
+{
+  "manifest_version": 2,
+  "name": "__MSG_appName__",
+  "version": "0",
+  "description": "__MSG_appDescription__",
+  "icons": {
+    "512": "icons/512.png",
+    "128": "icons/128.png"
+  },
+  "content_scripts": [
+    {
+      "matches": ["https://support.google.com/s/community*"],
+      "js": ["common/content_scripts.js", "content_scripts/console_inject.js"]
+    },
+    {
+      "matches": ["https://support.google.com/s/community*"],
+      "js": ["common/content_scripts.js", "content_scripts/console_inject_start.js"],
+      "css": ["common/console.css"],
+      "run_at": "document_start"
+    },
+    {
+      "matches": ["https://support.google.com/*/threads*"],
+      "js": ["content_scripts/forum_inject.js"]
+    },
+    {
+      "matches": ["https://support.google.com/*/thread/*"],
+      "exclude_matches": ["https://support.google.com/s/community*", "https://support.google.com/*/thread/new*"],
+      "js": ["common/content_scripts.js", "content_scripts/thread_inject.js"],
+      "run_at": "document_end"
+    },
+    {
+      "matches": ["https://support.google.com/s/community*", "https://support.google.com/*/thread/*"],
+      "exclude_matches": ["https://support.google.com/*/thread/new*"],
+      "js": ["common/content_scripts.js", "common/cs_event_listener.js", "content_scripts/profileindicator_inject.js"]
+    },
+    {
+      "matches": ["https://support.google.com/*/profile/*"],
+      "js": ["common/content_scripts.js", "content_scripts/profile_inject.js"],
+      "css": ["common/forum.css"]
+    }
+  ],
+  "permissions": [
+    "https://support.google.com/s/community*",
+    "https://support.google.com/*/threads*",
+    "https://support.google.com/*/thread/*",
+    "storage"
+  ],
+  "web_accessible_resources": [
+    "injections/profileindicator_inject.js",
+    "injections/profileindicator_inject.css",
+    "injections/ccdarktheme.css",
+    "injections/batchlock_inject.js"
+  ],
+  "browser_action": {},
+  "options_ui": {
+    "page": "options.html",
+    "browser_style": true,
+    "open_in_tab": false
+  },
+  "background": {
+    "scripts": [
+      "common/common.js",
+      "background.js"
+    ]
+  },
+  "browser_specific_settings": {
+    "gecko": {
+      "id": "twpowertools@avm99963.com",
+      "strict_min_version": "57.0"
+    }
+  },
+  "default_locale": "en"
+}
diff --git a/testdata/manifest_small1.gjson b/testdata/manifest_small1.gjson
new file mode 100644
index 0000000..5027087
--- /dev/null
+++ b/testdata/manifest_small1.gjson
@@ -0,0 +1,26 @@
+{
+  "foo": "option",
+#if defined(AAA)
+  "bar": 1,
+    #endif                   
+#if defined(    BBB )
+  "count": 2,
+  #if defined(B || C)    
+  "mmm": {},
+#endif
+#if defined(C)
+  #if defined(D)  
+  "ok": true,
+#endif
+#endif
+#if defined(D)
+#if defined(C)
+  "ok2": false,
+#endif
+#endif
+#endif
+#if defined(CDE || AAA)
+  "shouldBe": true,
+#endif
+  "so": 3.14
+}
diff --git a/testdata/manifest_small1_expected.json b/testdata/manifest_small1_expected.json
new file mode 100644
index 0000000..0e32581
--- /dev/null
+++ b/testdata/manifest_small1_expected.json
@@ -0,0 +1,7 @@
+{
+  "foo": "option",
+  "bar": 1,
+  "count": 2,
+  "shouldBe": true,
+  "so": 3.14
+}