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author | bojie <bojie@dexon.org> | 2018-12-28 13:15:06 +0800 |
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committer | Wei-Ning Huang <w@byzantine-lab.io> | 2019-06-12 17:27:20 +0800 |
commit | 3d46f69a10a60324ee6af0c96d064cc73ed5c37d (patch) | |
tree | ae9dd76f3f9a69c0acb18f6b0343601558d2e00f /vendor/google.golang.org/api/iterator/iterator.go | |
parent | 2426b985ae9773afe12f5a9f982cf4f2629f81a3 (diff) | |
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app: use gcp storage instead of azure for builds (#81)
* vendor: add dependencies for using GCP storage
* app: use gcp storage instead of azure for builds
Diffstat (limited to 'vendor/google.golang.org/api/iterator/iterator.go')
-rw-r--r-- | vendor/google.golang.org/api/iterator/iterator.go | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/vendor/google.golang.org/api/iterator/iterator.go b/vendor/google.golang.org/api/iterator/iterator.go new file mode 100644 index 000000000..3c8ea7732 --- /dev/null +++ b/vendor/google.golang.org/api/iterator/iterator.go @@ -0,0 +1,231 @@ +// Copyright 2016 Google LLC +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// Package iterator provides support for standard Google API iterators. +// See https://github.com/GoogleCloudPlatform/gcloud-golang/wiki/Iterator-Guidelines. +package iterator + +import ( + "errors" + "fmt" + "reflect" +) + +// Done is returned by an iterator's Next method when the iteration is +// complete; when there are no more items to return. +var Done = errors.New("no more items in iterator") + +// We don't support mixed calls to Next and NextPage because they play +// with the paging state in incompatible ways. +var errMixed = errors.New("iterator: Next and NextPage called on same iterator") + +// PageInfo contains information about an iterator's paging state. +type PageInfo struct { + // Token is the token used to retrieve the next page of items from the + // API. You may set Token immediately after creating an iterator to + // begin iteration at a particular point. If Token is the empty string, + // the iterator will begin with the first eligible item. + // + // The result of setting Token after the first call to Next is undefined. + // + // After the underlying API method is called to retrieve a page of items, + // Token is set to the next-page token in the response. + Token string + + // MaxSize is the maximum number of items returned by a call to the API. + // Set MaxSize as a hint to optimize the buffering behavior of the iterator. + // If zero, the page size is determined by the underlying service. + // + // Use Pager to retrieve a page of a specific, exact size. + MaxSize int + + // The error state of the iterator. Manipulated by PageInfo.next and Pager. + // This is a latch: it starts as nil, and once set should never change. + err error + + // If true, no more calls to fetch should be made. Set to true when fetch + // returns an empty page token. The iterator is Done when this is true AND + // the buffer is empty. + atEnd bool + + // Function that fetches a page from the underlying service. It should pass + // the pageSize and pageToken arguments to the service, fill the buffer + // with the results from the call, and return the next-page token returned + // by the service. The function must not remove any existing items from the + // buffer. If the underlying RPC takes an int32 page size, pageSize should + // be silently truncated. + fetch func(pageSize int, pageToken string) (nextPageToken string, err error) + + // Function that returns the number of currently buffered items. + bufLen func() int + + // Function that returns the buffer, after setting the buffer variable to nil. + takeBuf func() interface{} + + // Set to true on first call to PageInfo.next or Pager.NextPage. Used to check + // for calls to both Next and NextPage with the same iterator. + nextCalled, nextPageCalled bool +} + +// NewPageInfo exposes internals for iterator implementations. +// It is not a stable interface. +var NewPageInfo = newPageInfo + +// If an iterator can support paging, its iterator-creating method should call +// this (via the NewPageInfo variable above). +// +// The fetch, bufLen and takeBuf arguments provide access to the +// iterator's internal slice of buffered items. They behave as described in +// PageInfo, above. +// +// The return value is the PageInfo.next method bound to the returned PageInfo value. +// (Returning it avoids exporting PageInfo.next.) +func newPageInfo(fetch func(int, string) (string, error), bufLen func() int, takeBuf func() interface{}) (*PageInfo, func() error) { + pi := &PageInfo{ + fetch: fetch, + bufLen: bufLen, + takeBuf: takeBuf, + } + return pi, pi.next +} + +// Remaining returns the number of items available before the iterator makes another API call. +func (pi *PageInfo) Remaining() int { return pi.bufLen() } + +// next provides support for an iterator's Next function. An iterator's Next +// should return the error returned by next if non-nil; else it can assume +// there is at least one item in its buffer, and it should return that item and +// remove it from the buffer. +func (pi *PageInfo) next() error { + pi.nextCalled = true + if pi.err != nil { // Once we get an error, always return it. + // TODO(jba): fix so users can retry on transient errors? Probably not worth it. + return pi.err + } + if pi.nextPageCalled { + pi.err = errMixed + return pi.err + } + // Loop until we get some items or reach the end. + for pi.bufLen() == 0 && !pi.atEnd { + if err := pi.fill(pi.MaxSize); err != nil { + pi.err = err + return pi.err + } + if pi.Token == "" { + pi.atEnd = true + } + } + // Either the buffer is non-empty or pi.atEnd is true (or both). + if pi.bufLen() == 0 { + // The buffer is empty and pi.atEnd is true, i.e. the service has no + // more items. + pi.err = Done + } + return pi.err +} + +// Call the service to fill the buffer, using size and pi.Token. Set pi.Token to the +// next-page token returned by the call. +// If fill returns a non-nil error, the buffer will be empty. +func (pi *PageInfo) fill(size int) error { + tok, err := pi.fetch(size, pi.Token) + if err != nil { + pi.takeBuf() // clear the buffer + return err + } + pi.Token = tok + return nil +} + +// Pageable is implemented by iterators that support paging. +type Pageable interface { + // PageInfo returns paging information associated with the iterator. + PageInfo() *PageInfo +} + +// Pager supports retrieving iterator items a page at a time. +type Pager struct { + pageInfo *PageInfo + pageSize int +} + +// NewPager returns a pager that uses iter. Calls to its NextPage method will +// obtain exactly pageSize items, unless fewer remain. The pageToken argument +// indicates where to start the iteration. Pass the empty string to start at +// the beginning, or pass a token retrieved from a call to Pager.NextPage. +// +// If you use an iterator with a Pager, you must not call Next on the iterator. +func NewPager(iter Pageable, pageSize int, pageToken string) *Pager { + p := &Pager{ + pageInfo: iter.PageInfo(), + pageSize: pageSize, + } + p.pageInfo.Token = pageToken + if pageSize <= 0 { + p.pageInfo.err = errors.New("iterator: page size must be positive") + } + return p +} + +// NextPage retrieves a sequence of items from the iterator and appends them +// to slicep, which must be a pointer to a slice of the iterator's item type. +// Exactly p.pageSize items will be appended, unless fewer remain. +// +// The first return value is the page token to use for the next page of items. +// If empty, there are no more pages. Aside from checking for the end of the +// iteration, the returned page token is only needed if the iteration is to be +// resumed a later time, in another context (possibly another process). +// +// The second return value is non-nil if an error occurred. It will never be +// the special iterator sentinel value Done. To recognize the end of the +// iteration, compare nextPageToken to the empty string. +// +// It is possible for NextPage to return a single zero-length page along with +// an empty page token when there are no more items in the iteration. +func (p *Pager) NextPage(slicep interface{}) (nextPageToken string, err error) { + p.pageInfo.nextPageCalled = true + if p.pageInfo.err != nil { + return "", p.pageInfo.err + } + if p.pageInfo.nextCalled { + p.pageInfo.err = errMixed + return "", p.pageInfo.err + } + if p.pageInfo.bufLen() > 0 { + return "", errors.New("must call NextPage with an empty buffer") + } + // The buffer must be empty here, so takeBuf is a no-op. We call it just to get + // the buffer's type. + wantSliceType := reflect.PtrTo(reflect.ValueOf(p.pageInfo.takeBuf()).Type()) + if slicep == nil { + return "", errors.New("nil passed to Pager.NextPage") + } + vslicep := reflect.ValueOf(slicep) + if vslicep.Type() != wantSliceType { + return "", fmt.Errorf("slicep should be of type %s, got %T", wantSliceType, slicep) + } + for p.pageInfo.bufLen() < p.pageSize { + if err := p.pageInfo.fill(p.pageSize - p.pageInfo.bufLen()); err != nil { + p.pageInfo.err = err + return "", p.pageInfo.err + } + if p.pageInfo.Token == "" { + break + } + } + e := vslicep.Elem() + e.Set(reflect.AppendSlice(e, reflect.ValueOf(p.pageInfo.takeBuf()))) + return p.pageInfo.Token, nil +} |