Avoid unnecessary FooService allocations

Fixes google#389
Fixes google#390

github/activity.go

@@ -9,9 +9,7 @@ package github
 // methods of the GitHub API.
 //
 // GitHub API docs: http://developer.github.com/v3/activity/
-type ActivityService struct {
-	client *Client
-}
+type ActivityService service
 
 // FeedLink represents a link to a related resource.
 type FeedLink struct {

github/authorizations.go

@@ -47,9 +47,7 @@ const (
 // an OAuth token.
 //
 // GitHub API docs: https://developer.github.com/v3/oauth_authorizations/
-type AuthorizationsService struct {
-	client *Client
-}
+type AuthorizationsService service
 
 // Authorization represents an individual GitHub authorization.
 type Authorization struct {

github/gists.go

@@ -14,9 +14,7 @@ import (
 // methods of the GitHub API.
 //
 // GitHub API docs: http://developer.github.com/v3/gists/
-type GistsService struct {
-	client *Client
-}
+type GistsService service
 
 // Gist represents a GitHub's gist.
 type Gist struct {

github/git.go

@@ -9,6 +9,4 @@ package github
 // methods of the GitHub API.
 //
 // GitHub API docs: http://developer.github.com/v3/git/
-type GitService struct {
-	client *Client
-}
+type GitService service

github/github.go

@@ -108,6 +108,8 @@ type Client struct {
 	rateLimits [categories]Rate // Rate limits for the client as determined by the most recent API calls.
 	mostRecent rateLimitCategory
 
+	common service // Reuse a single struct instead of allocating one for each service on the heap.
+
 	// Services used for talking to different parts of the GitHub API.
 	Activity       *ActivityService
 	Authorizations *AuthorizationsService
@@ -125,6 +127,10 @@ type Client struct {
 	Reactions      *ReactionsService
 }
 
+type service struct {
+	client *Client
+}
+
 // ListOptions specifies the optional parameters to various List methods that
 // support pagination.
 type ListOptions struct {
@@ -174,20 +180,21 @@ func NewClient(httpClient *http.Client) *Client {
 	uploadURL, _ := url.Parse(uploadBaseURL)
 
 	c := &Client{client: httpClient, BaseURL: baseURL, UserAgent: userAgent, UploadURL: uploadURL}
-	c.Activity = &ActivityService{client: c}
-	c.Authorizations = &AuthorizationsService{client: c}
-	c.Gists = &GistsService{client: c}
-	c.Git = &GitService{client: c}
-	c.Gitignores = &GitignoresService{client: c}
-	c.Issues = &IssuesService{client: c}
-	c.Organizations = &OrganizationsService{client: c}
-	c.PullRequests = &PullRequestsService{client: c}
-	c.Repositories = &RepositoriesService{client: c}
-	c.Search = &SearchService{client: c}
-	c.Users = &UsersService{client: c}
-	c.Licenses = &LicensesService{client: c}
-	c.Migrations = &MigrationService{client: c}
-	c.Reactions = &ReactionsService{client: c}
+	c.common.client = c
+	c.Activity = (*ActivityService)(&c.common)
+	c.Authorizations = (*AuthorizationsService)(&c.common)
+	c.Gists = (*GistsService)(&c.common)
+	c.Git = (*GitService)(&c.common)
+	c.Gitignores = (*GitignoresService)(&c.common)
+	c.Issues = (*IssuesService)(&c.common)
+	c.Licenses = (*LicensesService)(&c.common)
+	c.Migrations = (*MigrationService)(&c.common)
+	c.Organizations = (*OrganizationsService)(&c.common)
+	c.PullRequests = (*PullRequestsService)(&c.common)
+	c.Reactions = (*ReactionsService)(&c.common)
+	c.Repositories = (*RepositoriesService)(&c.common)
+	c.Search = (*SearchService)(&c.common)
+	c.Users = (*UsersService)(&c.common)
 	return c
 }
 

github/gitignore.go

@@ -11,9 +11,7 @@ import "fmt"
 // GitHub API.
 //
 // GitHub API docs: http://developer.github.com/v3/gitignore/
-type GitignoresService struct {
-	client *Client
-}
+type GitignoresService service
 
 // Gitignore represents a .gitignore file as returned by the GitHub API.
 type Gitignore struct {

github/issues.go

@@ -14,9 +14,7 @@ import (
 // methods of the GitHub API.
 //
 // GitHub API docs: http://developer.github.com/v3/issues/
-type IssuesService struct {
-	client *Client
-}
+type IssuesService service
 
 // Issue represents a GitHub issue on a repository.
 type Issue struct {

github/licenses.go

@@ -11,9 +11,7 @@ import "fmt"
 // methods of the GitHub API.
 //
 // GitHub API docs: http://developer.github.com/v3/pulls/
-type LicensesService struct {
-	client *Client
-}
+type LicensesService service
 
 // License represents an open source license.
 type License struct {

github/migrations.go

@@ -16,9 +16,7 @@ import (
 // in the GitHub API.
 //
 // GitHub API docs: https://developer.github.com/v3/migration/
-type MigrationService struct {
-	client *Client
-}
+type MigrationService service
 
 // Migration represents a GitHub migration (archival).
 type Migration struct {

github/orgs.go

@@ -14,9 +14,7 @@ import (
 // in the GitHub API.
 //
 // GitHub API docs: http://developer.github.com/v3/orgs/
-type OrganizationsService struct {
-	client *Client
-}
+type OrganizationsService service
 
 // Organization represents a GitHub organization account.
 type Organization struct {

github/pulls.go

@@ -14,9 +14,7 @@ import (
 // methods of the GitHub API.
 //
 // GitHub API docs: http://developer.github.com/v3/pulls/
-type PullRequestsService struct {
-	client *Client
-}
+type PullRequestsService service
 
 // PullRequest represents a GitHub pull request on a repository.
 type PullRequest struct {

github/reactions.go

@@ -11,9 +11,7 @@ import "fmt"
 // GitHub API.
 //
 // GitHub API docs: https://developer.github.com/v3/reactions/
-type ReactionsService struct {
-	client *Client
-}
+type ReactionsService service
 
 // Reaction represents a GitHub reaction.
 type Reaction struct {

github/repos.go

@@ -11,9 +11,7 @@ import "fmt"
 // methods of the GitHub API.
 //
 // GitHub API docs: http://developer.github.com/v3/repos/
-type RepositoriesService struct {
-	client *Client
-}
+type RepositoriesService service
 
 // Repository represents a GitHub repository.
 type Repository struct {

github/search.go

@@ -15,9 +15,7 @@ import (
 // in the GitHub API.
 //
 // GitHub API docs: http://developer.github.com/v3/search/
-type SearchService struct {
-	client *Client
-}
+type SearchService service
 
 // SearchOptions specifies optional parameters to the SearchService methods.
 type SearchOptions struct {

github/users.go

@@ -11,9 +11,7 @@ import "fmt"
 // methods of the GitHub API.
 //
 // GitHub API docs: http://developer.github.com/v3/users/
-type UsersService struct {
-	client *Client
-}
+type UsersService service
 
 // User represents a GitHub user.
 type User struct {